Installing a cluster on VMC with user-provisioned infrastructure and network customizations

Setting up VMC for vSphere
- VMC Sizer tool
vSphere prerequisites
Internet access for OpenShift Container Platform
VMware vSphere infrastructure requirements
Machine requirements for a cluster with user-provisioned infrastructure
- Required machines
- Network connectivity requirements
- Minimum resource requirements
- Certificate signing requests management
Creating the user-provisioned infrastructure
- Networking requirements for user-provisioned infrastructure
- User-provisioned DNS requirements
Generating an SSH private key and adding it to the agent
Obtaining the installation program
Manually creating the installation configuration file
- Sample install-config.yaml file for VMware vSphere
- Configuring the cluster-wide proxy during installation
Specifying advanced network configuration
Cluster Network Operator configuration
- Cluster Network Operator configuration object
Creating the Ignition config files
Extracting the infrastructure name
Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines in vSphere
Creating more Red Hat Enterprise Linux CoreOS (RHCOS) machines in vSphere
Disk partitioning
Creating the cluster
Logging in to the cluster by using the CLI
Approving the certificate signing requests for your machines
Initial Operator configuration
- Image registry removed during installation
- Image registry storage configuration
Completing installation on user-provisioned infrastructure
Backing up VMware vSphere volumes
Telemetry access for OpenShift Container Platform
Next steps

In OpenShift Container Platform version 4.6, you can install a cluster on your VMware vSphere instance using infrastructure you provision with customized network configuration options by deploying it to VMware Cloud (VMC) on AWS.

Once you configure your VMC environment for OpenShift Container Platform deployment, you use the OpenShift Container Platform installation program from the bastion management host, co-located in the VMC environment. The installation program and control plane automates the process of deploying and managing the resources needed for the OpenShift Container Platform cluster.

By customizing your network configuration, your cluster can coexist with existing IP address allocations in your environment and integrate with existing VXLAN configurations. You must set most of the network configuration parameters during installation, and you can modify only kubeProxy configuration parameters in a running cluster.

OpenShift Container Platform supports deploying a cluster to a single VMware vCenter only. Deploying a cluster with machines/machine sets on multiple vCenters is not supported.

Setting up VMC for vSphere

You can install OpenShift Container Platform on VMware Cloud (VMC) on AWS hosted vSphere clusters to enable applications to be deployed and managed both on-premise and off-premise, across the hybrid cloud.

You must configure several options in your VMC environment prior to installing OpenShift Container Platform on VMware vSphere. Ensure your VMC environment has the following prerequisites:

Create a non-exclusive, DHCP-enabled, NSX-T network segment and subnet. Other virtual machines (VMs) can be hosted on the subnet, but at least eight IP addresses must be available for the OpenShift Container Platform deployment.
Configure the following firewall rules:
- An ANY:ANY firewall rule between the OpenShift Container Platform compute network and the Internet. This is used by nodes and applications to download container images.
- An ANY:ANY firewall rule between the installation host and the software-defined data center (SDDC) management network on port 443. This allows you to upload the Red Hat Enterprise Linux CoreOS (RHCOS) OVA during deployment.
- An HTTPS firewall rule between the OpenShift Container Platform compute network and vCenter. This connection allows OpenShift Container Platform to communicate with vCenter for provisioning and managing nodes, persistent volume claims (PVCs), and other resources.
You must have the following information to deploy OpenShift Container Platform:
- The OpenShift Container Platform cluster name, such as vmc-prod-1.
- The base DNS name, such as companyname.com.
- If not using the default, the pod network CIDR and services network CIDR must be identified, which are set by default to 10.128.0.0/14 and 172.30.0.0/16, respectively. These CIDRs are used for pod-to-pod and pod-to-service communication and are not accessible externally; however, they must not overlap with existing subnets in your organization.
- The following vCenter information:
  - vCenter hostname, username, and password
  - Datacenter name, such as SDDC-Datacenter
  - Cluster name, such as Cluster-1
  - Network name
  - Datastore name, such as WorkloadDatastore
    
    It is recommended to move your vSphere cluster to the VMC Compute-ResourcePool resource pool after your cluster installation is finished.
A Linux-based host deployed to VMC as a bastion.
- The bastion host can be Red Hat Enterprise Linux (RHEL) or any another Linux-based host; it must have Internet connectivity and the ability to upload an OVA to the ESXi hosts.
- Download and install the OpenShift CLI tools to the bastion host.
  - The openshift-install installation program
  - The OpenShift CLI (oc) tool

You cannot use the VMware NSX Container Plugin for Kubernetes (NCP), and NSX is not used as the OpenShift SDN. The version of NSX currently available with VMC is incompatible with the version of NCP certified with OpenShift Container Platform.

However, the NSX DHCP service is used for virtual machine IP management with the full-stack automated OpenShift Container Platform deployment and with nodes provisioned, either manually or automatically, by the Machine API integration with vSphere. Additionally, NSX firewall rules are created to enable access with the OpenShift Container Platform cluster and between the bastion host and the VMC vSphere hosts.

VMC Sizer tool

VMware Cloud on AWS is built on top of AWS bare metal infrastructure; this is the same bare metal infrastructure which runs AWS native services. When a VMware cloud on AWS software-defined data center (SDDC) is deployed, you consume these physical server nodes and run the VMware ESXi hypervisor in a single tenant fashion. This means the physical infrastructure is not accessible to anyone else using VMC. It is important to consider how many physical hosts you will need to host your virtual infrastructure.

To determine this, VMware provides the VMC on AWS Sizer. With this tool, you can define the resources you intend to host on VMC:

Types of workloads
Total number of virtual machines
Specification information such as:
- Storage requirements
- vCPUs
- vRAM
- Overcommit ratios

With these details, the sizer tool can generate a report, based on VMware best practices, and recommend your cluster configuration and the number of hosts you will need.

vSphere prerequisites

Provision block registry storage. For more information on persistent storage, see Understanding persistent storage.
Review details about the OpenShift Container Platform installation and update processes.
If you use a firewall, you must configure it to access Red Hat Insights.

Internet access for OpenShift Container Platform

In OpenShift Container Platform 4.6, you require access to the Internet to install your cluster.

You must have Internet access to:

Access OpenShift Cluster Manager to download the installation program and perform subscription management. If the cluster has internet access and you do not disable Telemetry, that service automatically entitles your cluster.
Access Quay.io to obtain the packages that are required to install your cluster.
Obtain the packages that are required to perform cluster updates.

If your cluster cannot have direct Internet access, you can perform a restricted network installation on some types of infrastructure that you provision. During that process, you download the content that is required and use it to populate a mirror registry with the packages that you need to install a cluster and generate the installation program. With some installation types, the environment that you install your cluster in will not require Internet access. Before you update the cluster, you update the content of the mirror registry.

VMware vSphere infrastructure requirements

You must install the OpenShift Container Platform cluster on a VMware vSphere version 6 or 7 instance that meets the requirements for the components that you use.

Table 1. Minimum supported vSphere version for VMware components
Component	Minimum supported versions	Description
Hypervisor	vSphere 6.5 and later with HW version 13	This version is the minimum version that Red Hat Enterprise Linux CoreOS (RHCOS) supports. See the Red Hat Enterprise Linux 8 supported hypervisors list.
Storage with in-tree drivers	vSphere 6.5 and later	This plug-in creates vSphere storage by using the in-tree storage drivers for vSphere included in OpenShift Container Platform.

If you use a vSphere version 6.5 instance, consider upgrading to 6.7U3 or 7.0 before you install OpenShift Container Platform.

You must ensure that the time on your ESXi hosts is synchronized before you install OpenShift Container Platform. See Edit Time Configuration for a Host in the VMware documentation.

Machine requirements for a cluster with user-provisioned infrastructure

For a cluster that contains user-provisioned infrastructure, you must deploy all of the required machines.

Required machines

The smallest OpenShift Container Platform clusters require the following hosts:

One temporary bootstrap machine
Three control plane, or master, machines
At least two compute machines, which are also known as worker machines.

The cluster requires the bootstrap machine to deploy the OpenShift Container Platform cluster on the three control plane machines. You can remove the bootstrap machine after you install the cluster.

To maintain high availability of your cluster, use separate physical hosts for these cluster machines.

The bootstrap and control plane machines must use Red Hat Enterprise Linux CoreOS (RHCOS) as the operating system. However, the compute machines can choose between Red Hat Enterprise Linux CoreOS (RHCOS) or Red Hat Enterprise Linux (RHEL) 7.9.

Note that RHCOS is based on Red Hat Enterprise Linux (RHEL) 8 and inherits all of its hardware certifications and requirements. See Red Hat Enterprise Linux technology capabilities and limits.

Network connectivity requirements

All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require network in initramfs during boot to fetch Ignition config files from the Machine Config Server. During the initial boot, the machines require either a DHCP server or that static IP addresses be set in order to establish a network connection to download their Ignition config files. Additionally, each OpenShift Container Platform node in the cluster must have access to a Network Time Protocol (NTP) server. If a DHCP server provides NTP servers information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.

Minimum resource requirements

Each cluster machine must meet the following minimum requirements:

Table 2. Minimum resource requirements
Machine	Operating System	vCPU ^[1]	Virtual RAM	Storage	IOPS ^[2]
Bootstrap	RHCOS	4	16 GB	100 GB	300
Control plane	RHCOS	4	16 GB	100 GB	300
Compute	RHCOS or RHEL 7.9	2	8 GB	100 GB	300

One vCPU is equivalent to one physical core when simultaneous multithreading (SMT), or hyperthreading, is not enabled. When enabled, use the following formula to calculate the corresponding ratio: (threads per core × cores) × sockets = vCPUs.
OpenShift Container Platform and Kubernetes are sensitive to disk performance, and faster storage is recommended, particularly for etcd on the control plane nodes which require a 10 ms p99 fsync duration. Note that on many cloud platforms, storage size and IOPS scale together, so you might need to over-allocate storage volume to obtain sufficient performance.

Certificate signing requests management

Because your cluster has limited access to automatic machine management when you use infrastructure that you provision, you must provide a mechanism for approving cluster certificate signing requests (CSRs) after installation. The kube-controller-manager only approves the kubelet client CSRs. The machine-approver cannot guarantee the validity of a serving certificate that is requested by using kubelet credentials because it cannot confirm that the correct machine issued the request. You must determine and implement a method of verifying the validity of the kubelet serving certificate requests and approving them.

Creating the user-provisioned infrastructure

Before you deploy an OpenShift Container Platform cluster that uses user-provisioned infrastructure, you must create the underlying infrastructure.

Prerequisites

Review the OpenShift Container Platform 4.x Tested Integrations page before you create the supporting infrastructure for your cluster.

Procedure

Configure DHCP or set static IP addresses on each node.
Provision the required load balancers.
Configure the ports for your machines.
Configure DNS.
Ensure network connectivity.

Networking requirements for user-provisioned infrastructure

All the Red Hat Enterprise Linux CoreOS (RHCOS) machines require network in initramfs during boot to fetch Ignition config from the machine config server.

During the initial boot, the machines require either a DHCP server or that static IP addresses be set on each host in the cluster in order to establish a network connection, which allows them to download their Ignition config files.

It is recommended to use the DHCP server to manage the machines for the cluster long-term. Ensure that the DHCP server is configured to provide persistent IP addresses and host names to the cluster machines.

The Kubernetes API server must be able to resolve the node names of the cluster machines. If the API servers and worker nodes are in different zones, you can configure a default DNS search zone to allow the API server to resolve the node names. Another supported approach is to always refer to hosts by their fully-qualified domain names in both the node objects and all DNS requests.

You must configure the network connectivity between machines to allow cluster components to communicate. Each machine must be able to resolve the host names of all other machines in the cluster.

Table 3. All machines to all machines
Protocol	Port	Description
ICMP	N/A	Network reachability tests
TCP	`1936`	Metrics
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101` and the Cluster Version Operator on port `9099`.
	`10250`-`10259`	The default ports that Kubernetes reserves
	`10256`	openshift-sdn
UDP	`4789`	VXLAN and Geneve
	`6081`	VXLAN and Geneve
	`9000`-`9999`	Host level services, including the node exporter on ports `9100`-`9101`.
TCP/UDP	`30000`-`32767`	Kubernetes node port

Table 4. All machines to control plane
Protocol	Port	Description
TCP	`6443`	Kubernetes API

Table 5. Control plane machines to control plane machines
Protocol	Port	Description
TCP	`2379`-`2380`	etcd server and peer ports

Network topology requirements

The infrastructure that you provision for your cluster must meet the following network topology requirements.

OpenShift Container Platform requires all nodes to have internet access to pull images for platform containers and provide telemetry data to Red Hat.

Load balancers

Before you install OpenShift Container Platform, you must provision two load balancers that meet the following requirements:

API load balancer: Provides a common endpoint for users, both human and machine, to interact with and configure the platform. Configure the following conditions:

Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the API routes.
A stateless load balancing algorithm. The options vary based on the load balancer implementation.

Do not configure session persistence for an API load balancer.

Configure the following ports on both the front and back of the load balancers:

Table 6. API load balancer
Port	Back-end machines (pool members)	Internal	External	Description
`6443`	Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane. You must configure the `/readyz` endpoint for the API server health check probe.	X	X	Kubernetes API server
`22623`	Bootstrap and control plane. You remove the bootstrap machine from the load balancer after the bootstrap machine initializes the cluster control plane.	X		Machine config server

The load balancer must be configured to take a maximum of 30 seconds from the time the API server turns off the /readyz endpoint to the removal of the API server instance from the pool. Within the time frame after /readyz returns an error or becomes healthy, the endpoint must have been removed or added. Probing every 5 or 10 seconds, with two successful requests to become healthy and three to become unhealthy, are well-tested values.

Application Ingress load balancer: Provides an Ingress point for application traffic flowing in from outside the cluster. Configure the following conditions:

Layer 4 load balancing only. This can be referred to as Raw TCP, SSL Passthrough, or SSL Bridge mode. If you use SSL Bridge mode, you must enable Server Name Indication (SNI) for the Ingress routes.
A connection-based or session-based persistence is recommended, based on the options available and types of applications that will be hosted on the platform.

Configure the following ports on both the front and back of the load balancers:

Table 7. Application Ingress load balancer
Port	Back-end machines (pool members)	Internal	External	Description
`443`	The machines that run the Ingress router pods, compute, or worker, by default.	X	X	HTTPS traffic
`80`	The machines that run the Ingress router pods, compute, or worker, by default.	X	X	HTTP traffic

If the true IP address of the client can be seen by the load balancer, enabling source IP-based session persistence can improve performance for applications that use end-to-end TLS encryption.

A working configuration for the Ingress router is required for an OpenShift Container Platform cluster. You must configure the Ingress router after the control plane initializes.

NTP configuration

OpenShift Container Platform clusters are configured to use a public Network Time Protocol (NTP) server by default. If you want to use a local enterprise NTP server, or if your cluster is being deployed in a disconnected network, you can configure the cluster to use a specific time server. For more information, see the documentation for Configuring chrony time service.

If a DHCP server provides NTP server information, the chrony time service on the Red Hat Enterprise Linux CoreOS (RHCOS) machines read the information and can sync the clock with the NTP servers.

User-provisioned DNS requirements

DNS is used for name resolution and reverse name resolution. DNS A/AAAA or CNAME records are used for name resolution and PTR records are used for reverse name resolution. The reverse records are important because Red Hat Enterprise Linux CoreOS (RHCOS) uses the reverse records to set the host name for all the nodes. Additionally, the reverse records are used to generate the certificate signing requests (CSR) that OpenShift Container Platform needs to operate.

The following DNS records are required for an OpenShift Container Platform cluster that uses user-provisioned infrastructure. In each record, <cluster_name> is the cluster name and <base_domain> is the cluster base domain that you specify in the install-config.yaml file. A complete DNS record takes the form: <component>.<cluster_name>.<base_domain>..

Component Record Description

Kubernetes API

api.<cluster_name>.<base_domain>.

Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

api-int.<cluster_name>.<base_domain>.

Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the load balancer for the control plane machines. These records must be resolvable from all the nodes within the cluster.

The API server must be able to resolve the worker nodes by the host names that are recorded in Kubernetes. If the API server cannot resolve the node names, then proxied API calls can fail, and you cannot retrieve logs from pods.

Routes

*.apps.<cluster_name>.<base_domain>.

Add a wildcard DNS A/AAAA or CNAME record that refers to the load balancer that targets the machines that run the Ingress router pods, which are the worker nodes by default. These records must be resolvable by both clients external to the cluster and from all the nodes within the cluster.

Bootstrap

bootstrap.<cluster_name>.<base_domain>.

Add a DNS A/AAAA or CNAME record, and a DNS PTR record, to identify the bootstrap machine. These records must be resolvable by the nodes within the cluster.

Master hosts

<master><n>.<cluster_name>.<base_domain>.

DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the control plane nodes (also known as the master nodes). These records must be resolvable by the nodes within the cluster.

Worker hosts

<worker><n>.<cluster_name>.<base_domain>.

Add DNS A/AAAA or CNAME records and DNS PTR records to identify each machine for the worker nodes. These records must be resolvable by the nodes within the cluster.

You can use the nslookup <hostname> command to verify name resolution. You can use the dig -x <ip_address> command to verify reverse name resolution for the PTR records.

The following example of a BIND zone file shows sample A records for name resolution. The purpose of the example is to show the records that are needed. The example is not meant to provide advice for choosing one name resolution service over another.

Sample DNS zone database

$TTL 1W
@	IN	SOA	ns1.example.com.	root (
			2019070700	; serial
			3H		; refresh (3 hours)
			30M		; retry (30 minutes)
			2W		; expiry (2 weeks)
			1W )		; minimum (1 week)
	IN	NS	ns1.example.com.
	IN	MX 10	smtp.example.com.
;
;
ns1	IN	A	192.168.1.5
smtp	IN	A	192.168.1.5
;
helper	IN	A	192.168.1.5
helper.ocp4	IN	A	192.168.1.5
;
; The api identifies the IP of your load balancer.
api.ocp4		IN	A	192.168.1.5
api-int.ocp4		IN	A	192.168.1.5
;
; The wildcard also identifies the load balancer.
*.apps.ocp4		IN	A	192.168.1.5
;
; Create an entry for the bootstrap host.
bootstrap.ocp4	IN	A	192.168.1.96
;
; Create entries for the master hosts.
master0.ocp4		IN	A	192.168.1.97
master1.ocp4		IN	A	192.168.1.98
master2.ocp4		IN	A	192.168.1.99
;
; Create entries for the worker hosts.
worker0.ocp4		IN	A	192.168.1.11
worker1.ocp4		IN	A	192.168.1.7
;
;EOF

The following example BIND zone file shows sample PTR records for reverse name resolution.

Sample DNS zone database for reverse records

$TTL 1W
@	IN	SOA	ns1.example.com.	root (
			2019070700	; serial
			3H		; refresh (3 hours)
			30M		; retry (30 minutes)
			2W		; expiry (2 weeks)
			1W )		; minimum (1 week)
	IN	NS	ns1.example.com.
;
; The syntax is "last octet" and the host must have an FQDN
; with a trailing dot.
97	IN	PTR	master0.ocp4.example.com.
98	IN	PTR	master1.ocp4.example.com.
99	IN	PTR	master2.ocp4.example.com.
;
96	IN	PTR	bootstrap.ocp4.example.com.
;
5	IN	PTR	api.ocp4.example.com.
5	IN	PTR	api-int.ocp4.example.com.
;
11	IN	PTR	worker0.ocp4.example.com.
7	IN	PTR	worker1.ocp4.example.com.
;
;EOF

Generating an SSH private key and adding it to the agent

If you want to perform installation debugging or disaster recovery on your cluster, you must provide an SSH key to both your ssh-agent and the installation program. You can use this key to access the bootstrap machine in a public cluster to troubleshoot installation issues.

In a production environment, you require disaster recovery and debugging.

You can use this key to SSH into the master nodes as the user core. When you deploy the cluster, the key is added to the core user’s ~/.ssh/authorized_keys list.

You must use a local key, not one that you configured with platform-specific approaches such as AWS key pairs.

Procedure

If you do not have an SSH key that is configured for password-less authentication on your computer, create one. For example, on a computer that uses a Linux operating system, run the following command:

$ ssh-keygen -t ed25519 -N '' \
    -f <path>/<file_name> (1)

1	Specify the path and file name, such as `~/.ssh/id_rsa`, of the new SSH key. If you have an existing key pair, ensure your public key is in the your `~/.ssh` directory.

Running this command generates an SSH key that does not require a password in the location that you specified.

If you plan to install an OpenShift Container Platform cluster that uses fips Validated / Modules in Process cryptographic libraries on the x86_64 architecture, do not create a key that uses the ed25519 algorithm. Instead, create a key that uses the rsa or ecdsa algorithm.

Start the ssh-agent process as a background task:
```
$ eval "$(ssh-agent -s)"
```
Example output
```
Agent pid 31874
```
If your cluster is in fips mode, only use fips-compliant algorithms to generate the SSH key. The key must be either RSA or ECDSA.
Add your SSH private key to the ssh-agent:
```
$ ssh-add <path>/<file_name> (1)
```
Example output
```
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
```
1 Specify the path and file name for your SSH private key, such as ~/.ssh/id_rsa

Next steps

When you install OpenShift Container Platform, provide the SSH public key to the installation program.

Obtaining the installation program

Before you install OpenShift Container Platform, download the installation file on a local computer.

Prerequisites

You have a computer that runs Linux or macOS, with 500 MB of local disk space

Procedure

Access the Infrastructure Provider page on the OpenShift Cluster Manager site. If you have a Red Hat account, log in with your credentials. If you do not, create an account.
Select your infrastructure provider.

Navigate to the page for your installation type, download the installation program for your operating system, and place the file in the directory where you will store the installation configuration files.

The installation program creates several files on the computer that you use to install your cluster. You must keep the installation program and the files that the installation program creates after you finish installing the cluster. Both files are required to delete the cluster.

Deleting the files created by the installation program does not remove your cluster, even if the cluster failed during installation. To remove your cluster, complete the OpenShift Container Platform uninstallation procedures for your specific cloud provider.

Extract the installation program. For example, on a computer that uses a Linux operating system, run the following command:
```
$ tar xvf openshift-install-linux.tar.gz
```
Download your installation pull secret from the Red Hat OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.

Manually creating the installation configuration file

For installations of OpenShift Container Platform that use user-provisioned infrastructure, you manually generate your installation configuration file.

Prerequisites

Obtain the OpenShift Container Platform installation program and the access token for your cluster.

Procedure

Create an installation directory to store your required installation assets in:

$ mkdir <installation_directory>

You must create a directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.

Customize the following install-config.yaml file template and save it in the <installation_directory>.

You must name this configuration file install-config.yaml.
Back up the install-config.yaml file so that you can use it to install multiple clusters.

The install-config.yaml file is consumed during the next step of the installation process. You must back it up now.

Sample `install-config.yaml` file for VMware vSphere

You can customize the install-config.yaml file to specify more details about your OpenShift Container Platform cluster’s platform or modify the values of the required parameters.

apiVersion: v1
baseDomain: example.com (1)
compute:
- hyperthreading: Enabled  (2) (3)
  name: worker
  replicas: 0 (4)
controlPlane:
  hyperthreading: Enabled  (2) (3)
  name: master
  replicas: 3 (5)
metadata:
  name: test (6)
platform:
  vsphere:
    vcenter: your.vcenter.server (7)
    username: username (8)
    password: password (9)
    datacenter: datacenter (10)
    defaultDatastore: datastore (11)
    folder: "/<datacenter_name>/vm/<folder_name>/<subfolder_name>" (12)
fips: false (13)
pullSecret: '{"auths": ...}' (14)
sshKey: 'ssh-ed25519 AAAA...' (15)

1 The base domain of the cluster. All DNS records must be sub-domains of this base and include the cluster name.

2 The controlPlane section is a single mapping, but the compute section is a sequence of mappings. To meet the requirements of the different data structures, the first line of the compute section must begin with a hyphen, -, and the first line of the controlPlane section must not. Although both sections currently define a single machine pool, it is possible that future versions of OpenShift Container Platform will support defining multiple compute pools during installation. Only one control plane pool is used.

Whether to enable or disable simultaneous multithreading, or hyperthreading. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores. You can disable it by setting the parameter value to Disabled. If you disable simultaneous multithreading in some cluster machines, you must disable it in all cluster machines.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance. Your machines must use at least 8 CPUs and 32 GB of RAM if you disable simultaneous multithreading.

4 You must set the value of the replicas parameter to 0. This parameter controls the number of workers that the cluster creates and manages for you, which are functions that the cluster does not perform when you use user-provisioned infrastructure. You must manually deploy worker machines for the cluster to use before you finish installing OpenShift Container Platform.

5 The number of control plane machines that you add to the cluster. Because the cluster uses this values as the number of etcd endpoints in the cluster, the value must match the number of control plane machines that you deploy.

6 The cluster name that you specified in your DNS records.

7 The fully-qualified hostname or IP address of the vCenter server.

8 The name of the user for accessing the server. This user must have at least the roles and privileges that are required for static or dynamic persistent volume provisioning in vSphere.

9 The password associated with the vSphere user.

10 The vSphere datacenter.

11 The default vSphere datastore to use.

12 Optional: For installer-provisioned infrastructure, the absolute path of an existing folder where the installation program creates the virtual machines, for example, /<datacenter_name>/vm/<folder_name>/<subfolder_name>. If you do not provide this value, the installation program creates a top-level folder in the datacenter virtual machine folder that is named with the infrastructure ID. If you are providing the infrastructure for the cluster, omit this parameter.

Whether to enable or disable fips mode. By default, fips mode is not enabled. If fips mode is enabled, the Red Hat Enterprise Linux CoreOS (RHCOS) machines that OpenShift Container Platform runs on bypass the default Kubernetes cryptography suite and use the cryptography modules that are provided with RHCOS instead.

The use of fips Validated / Modules in Process cryptographic libraries is only supported on OpenShift Container Platform deployments on the x86_64 architecture.

14 The pull secret that you obtained from OpenShift Cluster Manager. This pull secret allows you to authenticate with the services that are provided by the included authorities, including Quay.io, which serves the container images for OpenShift Container Platform components.

15 The public portion of the default SSH key for the core user in Red Hat Enterprise Linux CoreOS (RHCOS).

Configuring the cluster-wide proxy during installation

Production environments can deny direct access to the Internet and instead have an HTTP or HTTPS proxy available. You can configure a new OpenShift Container Platform cluster to use a proxy by configuring the proxy settings in the install-config.yaml file.

Prerequisites

You have an existing install-config.yaml file.

You reviewed the sites that your cluster requires access to and determined whether any of them need to bypass the proxy. By default, all cluster egress traffic is proxied, including calls to hosting cloud provider APIs. You added sites to the Proxy object’s spec.noProxy field to bypass the proxy if necessary.

The Proxy object status.noProxy field is populated with the values of the networking.machineNetwork[].cidr, networking.clusterNetwork[].cidr, and networking.serviceNetwork[] fields from your installation configuration.

For installations on Amazon Web Services (AWS), Google Cloud Platform (GCP), Microsoft Azure, and Red Hat OpenStack Platform (RHOSP), the Proxy object status.noProxy field is also populated with the instance metadata endpoint (169.254.169.254).

Procedure

Edit your install-config.yaml file and add the proxy settings. For example:

apiVersion: v1
baseDomain: my.domain.com
proxy:
  httpProxy: http://<username>:<pswd>@<ip>:<port> (1)
  httpsProxy: https://<username>:<pswd>@<ip>:<port> (2)
  noProxy: example.com (3)
additionalTrustBundle: | (4)
    -----BEGIN CERTIFICATE-----
    <MY_TRUSTED_CA_CERT>
    -----END CERTIFICATE-----
...

1	A proxy URL to use for creating HTTP connections outside the cluster. The URL scheme must be `http`.
2	A proxy URL to use for creating HTTPS connections outside the cluster.
3	A comma-separated list of destination domain names, IP addresses, or other network CIDRs to exclude from proxying. Preface a domain with `.` to match subdomains only. For example, `.y.com` matches `x.y.com`, but not `y.com`. Use `*` to bypass the proxy for all destinations. You must include vCenter’s IP address and the IP range that you use for its machines.
4	If provided, the installation program generates a config map that is named `user-ca-bundle` in the `openshift-config` namespace to hold the additional CA certificates. If you provide `additionalTrustBundle` and at least one proxy setting, the `Proxy` object is configured to reference the `user-ca-bundle` config map in the `trustedCA` field. The Cluster Network Operator then creates a `trusted-ca-bundle` config map that merges the contents specified for the `trustedCA` parameter with the RHCOS trust bundle. The `additionalTrustBundle` field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle.

The installation program does not support the proxy readinessEndpoints field.

Save the file and reference it when installing OpenShift Container Platform.

The installation program creates a cluster-wide proxy that is named cluster that uses the proxy settings in the provided install-config.yaml file. If no proxy settings are provided, a cluster Proxy object is still created, but it will have a nil spec.

Only the Proxy object named cluster is supported, and no additional proxies can be created.

Specifying advanced network configuration

You can use advanced configuration customization to integrate your cluster into your existing network environment by specifying additional configuration for your cluster network provider. You can specify advanced network configuration only before you install the cluster.

Modifying the OpenShift Container Platform manifest files created by the installation program is not supported. Applying a manifest file that you create, as in the following procedure, is supported.

Prerequisites

Create the install-config.yaml file and complete any modifications to it.
Create the Ignition config files for your cluster.

Procedure

Change to the directory that contains the installation program and create the manifests:
```
$ ./openshift-install create manifests --dir <installation_directory>
```
where:

<installation_directory>

Specifies the name of the directory that contains the install-config.yaml file for your cluster.
Create a stub manifest file for the advanced network configuration that is named cluster-network-03-config.yml in the <installation_directory>/manifests/ directory:
```
$ cat <<EOF > <installation_directory>/manifests/cluster-network-03-config.yml
apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
EOF
```
where:

<installation_directory>

Specifies the directory name that contains the manifests/ directory for your cluster.
Open the cluster-network-03-config.yml file in an editor and specify the advanced network configuration for your cluster, such as in the following example:
Specify a different VXLAN port for the OpenShift SDN network provider
apiVersion: operator.openshift.io/v1 kind: Network metadata: name: cluster spec: defaultNetwork: openshiftSDNConfig: vxlanPort: 4800
Save the cluster-network-03-config.yml file and quit the text editor.
Optional: Back up the manifests/cluster-network-03-config.yml file. The installation program deletes the manifests/ directory when creating the cluster.
Remove the Kubernetes manifest files that define the control plane machines and compute machineSets:
```
$ rm -f openshift/99_openshift-cluster-api_master-machines-*.yaml openshift/99_openshift-cluster-api_worker-machineset-*.yaml
```
Because you create and manage these resources yourself, you do not have to initialize them.
- You can preserve the MachineSet files to create compute machines by using the machine API, but you must update references to them to match your environment.

Cluster Network Operator configuration

The configuration for the cluster network is specified as part of the Cluster Network Operator (CNO) configuration and stored in a custom resource (CR) object that is named cluster. The CR specifies the fields for the Network API in the operator.openshift.io API group.

The CNO configuration inherits the following fields during cluster installation from the Network API in the Network.config.openshift.io API group and these fields cannot be changed:

clusterNetwork: IP address pools from which pod IP addresses are allocated.
serviceNetwork: IP address pool for services.
defaultNetwork.type: Cluster network provider, such as OpenShift SDN or OVN-Kubernetes.

You can specify the cluster network provider configuration for your cluster by setting the fields for the defaultNetwork object in the CNO object named cluster.

Cluster Network Operator configuration object

The fields for the Cluster Network Operator (CNO) are described in the following table:

Table 9. Cluster Network Operator configuration object
Field	Type	Description
`metadata.name`	`string`	The name of the CNO object. This name is always `cluster`.
`spec.clusterNetwork`	`array`	A list specifying the blocks of IP addresses from which pod IP addresses are allocated and the subnet prefix length assigned to each individual node in the cluster. For example: `spec: clusterNetwork: - cidr: 10.128.0.0/19 hostPrefix: 23 - cidr: 10.128.32.0/19 hostPrefix: 23` This value is ready-only and specified in the `install-config.yaml` file.
`spec.serviceNetwork`	`array`	A block of IP addresses for services. The OpenShift SDN and OVN-Kubernetes Container Network Interface (CNI) network providers support only a single IP address block for the service network. For example: `spec: serviceNetwork: - 172.30.0.0/14` This value is ready-only and specified in the `install-config.yaml` file.
`spec.defaultNetwork`	`object`	Configures the Container Network Interface (CNI) cluster network provider for the cluster network.
`spec.kubeProxyConfig`	`object`	The fields for this object specify the kube-proxy configuration. If you are using the OVN-Kubernetes cluster network provider, the kube-proxy configuration has no effect.

defaultNetwork object configuration

The values for the defaultNetwork object are defined in the following table:

Field Type Description

type

string

Either OpenShiftSDN or OVNKubernetes. The cluster network provider is selected during installation. This value cannot be changed after cluster installation.

OpenShift Container Platform uses the OpenShift SDN Container Network Interface (CNI) cluster network provider by default.

openshiftSDNConfig

object

This object is only valid for the OpenShift SDN cluster network provider.

ovnKubernetesConfig

object

This object is only valid for the OVN-Kubernetes cluster network provider.

Configuration for the OpenShift SDN CNI cluster network provider

The following table describes the configuration fields for the OpenShift SDN Container Network Interface (CNI) cluster network provider.

Table 11. `openshiftSDNConfig` object
Field	Type	Description
`mode`	`string`	Configures the network isolation mode for OpenShift SDN. The default value is `NetworkPolicy`. The values `Multitenant` and `Subnet` are available for backwards compatibility with OpenShift Container Platform 3.x but are not recommended. This value cannot be changed after cluster installation.
`mtu`	`integer`	The maximum transmission unit (MTU) for the VXLAN overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expected it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes. If your cluster requires different MTU values for different nodes, you must set this value to `50` less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of `9001`, and some have an MTU of `1500`, you must set this value to `1450`. This value cannot be changed after cluster installation.
`vxlanPort`	`integer`	The port to use for all VXLAN packets. The default value is `4789`. This value cannot be changed after cluster installation. If you are running in a virtualized environment with existing nodes that are part of another VXLAN network, then you might be required to change this. For example, when running an OpenShift SDN overlay on top of VMware NSX-T, you must select an alternate port for the VXLAN, because both SDNs use the same default VXLAN port number. On Amazon Web Services (AWS), you can select an alternate port for the VXLAN between port `9000` and port `9999`.

Example OpenShift SDN configuration

defaultNetwork:
  type: OpenShiftSDN
  openshiftSDNConfig:
    mode: NetworkPolicy
    mtu: 1450
    vxlanPort: 4789

Configuration for the OVN-Kubernetes CNI cluster network provider

The following table describes the configuration fields for the OVN-Kubernetes CNI cluster network provider.

Table 12. `ovnKubernetesConfig` object
Field	Type	Description
`mtu`	`integer`	The maximum transmission unit (MTU) for the Geneve (Generic Network Virtualization Encapsulation) overlay network. This is detected automatically based on the MTU of the primary network interface. You do not normally need to override the detected MTU. If the auto-detected value is not what you expected it to be, confirm that the MTU on the primary network interface on your nodes is correct. You cannot use this option to change the MTU value of the primary network interface on the nodes. If your cluster requires different MTU values for different nodes, you must set this value to `100` less than the lowest MTU value in your cluster. For example, if some nodes in your cluster have an MTU of `9001`, and some have an MTU of `1500`, you must set this value to `1400`. This value cannot be changed after cluster installation.
`genevePort`	`integer`	The port to use for all Geneve packets. The default value is `6081`. This value cannot be changed after cluster installation.

Example OVN-Kubernetes configuration

defaultNetwork:
  type: OVNKubernetes
  ovnKubernetesConfig:
    mtu: 1400
    genevePort: 6081

kubeProxyConfig object configuration

The values for the kubeProxyConfig object are defined in the following table:

Field Type Description

iptablesSyncPeriod

string

The refresh period for iptables rules. The default value is 30s. Valid suffixes include s, m, and h and are described in the Go time package documentation.

Because of performance improvements introduced in OpenShift Container Platform 4.3 and greater, adjusting the iptablesSyncPeriod parameter is no longer necessary.

proxyArguments.iptables-min-sync-period

array

The minimum duration before refreshing iptables rules. This field ensures that the refresh does not happen too frequently. Valid suffixes include s, m, and h and are described in the Go time package. The default value is:

kubeProxyConfig:
  proxyArguments:
    iptables-min-sync-period:
    - 0s

Creating the Ignition config files

Because you must manually start the cluster machines, you must generate the Ignition config files that the cluster needs to make its machines.

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Prerequisites

Obtain the OpenShift Container Platform installation program and the pull secret for your cluster. For a restricted network installation, these files are on your mirror host.

Procedure

Obtain the Ignition config files:

$ ./openshift-install create ignition-configs --dir <installation_directory> (1)

1	For `<installation_directory>`, specify the directory name to store the files that the installation program creates.

If you created an install-config.yaml file, specify the directory that contains it. Otherwise, specify an empty directory. Some installation assets, like bootstrap X.509 certificates have short expiration intervals, so you must not reuse an installation directory. If you want to reuse individual files from another cluster installation, you can copy them into your directory. However, the file names for the installation assets might change between releases. Use caution when copying installation files from an earlier OpenShift Container Platform version.

The following files are generated in the directory:

.
├── auth
│   ├── kubeadmin-password
│   └── kubeconfig
├── bootstrap.ign
├── master.ign
├── metadata.json
└── worker.ign

Extracting the infrastructure name

The Ignition config files contain a unique cluster identifier that you can use to uniquely identify your cluster in VMware Cloud on AWS. If you plan to use the cluster identifier as the name of your virtual machine folder, you must extract it.

Prerequisites

You obtained the OpenShift Container Platform installation program and the pull secret for your cluster.
You generated the Ignition config files for your cluster.
You installed the jq package.

Procedure

To extract and view the infrastructure name from the Ignition config file metadata, run the following command:
```
$ jq -r .infraID <installation_directory>/metadata.json (1)
```
1 For <installation_directory>, specify the path to the directory that you stored the installation files in.
Example output
```
openshift-vw9j6 (1)
```
1 The output of this command is your cluster name and a random string.

Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines in vSphere

Before you install a cluster that contains user-provisioned infrastructure on VMware vSphere, you must create RHCOS machines on vSphere hosts for it to use.

Prerequisites

You have obtained the Ignition config files for your cluster.
You have access to an HTTP server that you can access from your computer and that the machines that you create can access.
You have created a vSphere cluster.

Procedure

Upload the bootstrap Ignition config file, which is named <installation_directory>/bootstrap.ign, that the installation program created to your HTTP server. Note the URL of this file.
Save the following secondary Ignition config file for your bootstrap node to your computer as <installation_directory>/merge-bootstrap.ign:
```
{
  "ignition": {
    "config": {
      "merge": [
        {
          "source": "<bootstrap_ignition_config_url>", (1)
          "verification": {}
        }
      ]
    },
    "timeouts": {},
    "version": "3.1.0"
  },
  "networkd": {},
  "passwd": {},
  "storage": {},
  "systemd": {}
}
```
1 Specify the URL of the bootstrap Ignition config file that you hosted.

When you create the virtual machine (VM) for the bootstrap machine, you use this Ignition config file.
Locate the following Ignition config files that the installation program created:
- <installation_directory>/master.ign
- <installation_directory>/worker.ign
- <installation_directory>/merge-bootstrap.ign
Convert the Ignition config files to Base64 encoding. Later in this procedure, you must add these files to the extra configuration parameter guestinfo.ignition.config.data in your VM.

For example, if you use a Linux operating system, you can use the base64 command to encode the files.
```
$ base64 -w0 <installation_directory>/master.ign > <installation_directory>/master.64
```
```
$ base64 -w0 <installation_directory>/worker.ign > <installation_directory>/worker.64
```
```
$ base64 -w0 <installation_directory>/merge-bootstrap.ign > <installation_directory>/merge-bootstrap.64
```
If you plan to add more compute machines to your cluster after you finish installation, do not delete these files.

Obtain the RHCOS OVA image. Images are available from the RHCOS image mirror page.

The RHCOS images might not change with every release of OpenShift Container Platform. You must download an image with the highest version that is less than or equal to the OpenShift Container Platform version that you install. Use the image version that matches your OpenShift Container Platform version if it is available.

The filename contains the OpenShift Container Platform version number in the format rhcos-vmware.<architecture>.ova.

In the vSphere Client, create a folder in your datacenter to store your VMs.
1. Click the VMs and Templates view.
2. Right-click the name of your datacenter.
3. Click New Folder → New VM and Template Folder.
4. In the window that is displayed, enter the folder name. If you did not specify an existing folder in the install-config.yaml file, then create a folder with the same name as the infrastructure ID. You use this folder name so vCenter dynamically provisions storage in the appropriate location for its Workspace configuration.

In the vSphere Client, create a template for the OVA image and then clone the template as needed.

In the following steps, you create a template and then clone the template for all of your cluster machines. You then provide the location for the Ignition config file for that cloned machine type when you provision the VMs.

From the Hosts and Clusters tab, right-click your cluster name and select Deploy OVF Template.
On the Select an OVF tab, specify the name of the RHCOS OVA file that you downloaded.
On the Select a name and folder tab, set a Virtual machine name for your template, such as Template-RHCOS. Click the name of your vSphere cluster and select the folder you created in the previous step.
On the Select a compute resource tab, click the name of your vSphere cluster.
On the Select storage tab, configure the storage options for your VM.
- Select Thin Provision or Thick Provision, based on your storage preferences.
- Select the datastore that you specified in your install-config.yaml file.
On the Select network tab, specify the network that you configured for the cluster, if available.

When creating the OVF template, do not specify values on the Customize template tab or configure the template any further.

Do not start the original VM template. The VM template must remain off and must be cloned for new RHCOS machines. Starting the VM template configures the VM template as a VM on the platform, which prevents it from being used as a template that machine sets can apply configurations to.

After the template deploys, deploy a VM for a machine in the cluster.
1. Right-click the template name and click Clone → Clone to Virtual Machine.
2. On the Select a name and folder tab, specify a name for the VM. You might include the machine type in the name, such as control-plane-0 or compute-1.
3. On the Select a name and folder tab, select the name of the folder that you created for the cluster.
4. On the Select a compute resource tab, select the name of a host in your datacenter.
  
  For a bootstrap machine, specify the URL of the bootstrap Ignition config file that you hosted.
5. Optional: On the Select storage tab, customize the storage options.
6. On the Select clone options, select Customize this virtual machine’s hardware.
7. On the Customize hardware tab, click VM Options → Advanced.
  - Optional: Override default DHCP networking in vSphere. To enable static IP networking:
    
    Set your static IP configuration:
    
    $ export IPCFG="ip=<ip>::<gateway>:<netmask>:<hostname>:<iface>:none nameserver=srv1 [nameserver=srv2 [nameserver=srv3 [...]]]"
    
    Example command
    
    $ export IPCFG="ip=192.168.100.101::192.168.100.254:255.255.255.0:::none nameserver=8.8.8.8"
    
    Set the guestinfo.afterburn.initrd.network-kargs property before booting a VM from an OVA in vSphere:
    
    $ govc vm.change -vm "<vm_name>" -e "guestinfo.afterburn.initrd.network-kargs=${IPCFG}"
  - Optional: In the event of cluster performance issues, from the Latency Sensitivity list, select High. Ensure that your VM’s CPU and memory reservation have the following values:
    
    Memory reservation value must be equal to its configured memory size.
    
    CPU reservation value must be at least the number of low latency virtual CPUs multiplied by the measured physical CPU speed.
  - Click Edit Configuration, and on the Configuration Parameters window, click Add Configuration Params. Define the following parameter names and values:
    
    guestinfo.ignition.config.data: Locate the base-64 encoded files that you created previously in this procedure, and paste the contents of the base64-encoded Ignition config file for this machine type.
    
    guestinfo.ignition.config.data.encoding: Specify base64.
    
    disk.EnableUUID: Specify TRUE.
8. In the Virtual Hardware panel of the Customize hardware tab, modify the specified values as required. Ensure that the amount of RAM, CPU, and disk storage meets the minimum requirements for the machine type.
9. Complete the configuration and power on the VM.

Create the rest of the machines for your cluster by following the preceding steps for each machine.

You must create the bootstrap and control plane machines at this time. Because some pods are deployed on compute machines by default, also create at least two compute machines before you install the cluster.

Creating more Red Hat Enterprise Linux CoreOS (RHCOS) machines in vSphere

You can create more compute machines for your cluster that uses user-provisioned infrastructure on VMware vSphere.

Prerequisites

Obtain the base64-encoded Ignition file for your compute machines.
You have access to the vSphere template that you created for your cluster.

Procedure

After the template deploys, deploy a VM for a machine in the cluster.
1. Right-click the template’s name and click Clone → Clone to Virtual Machine.
2. On the Select a name and folder tab, specify a name for the VM. You might include the machine type in the name, such as compute-1.
3. On the Select a name and folder tab, select the name of the folder that you created for the cluster.
4. On the Select a compute resource tab, select the name of a host in your datacenter.
5. Optional: On the Select storage tab, customize the storage options.
6. On the Select clone options, select Customize this virtual machine’s hardware.
7. On the Customize hardware tab, click VM Options → Advanced.
  - From the Latency Sensitivity list, select High.
  - Click Edit Configuration, and on the Configuration Parameters window, click Add Configuration Params. Define the following parameter names and values:
    
    guestinfo.ignition.config.data: Paste the contents of the base64-encoded compute Ignition config file for this machine type.
    
    guestinfo.ignition.config.data.encoding: Specify base64.
    
    disk.EnableUUID: Specify TRUE.
8. In the Virtual Hardware panel of the Customize hardware tab, modify the specified values as required. Ensure that the amount of RAM, CPU, and disk storage meets the minimum requirements for the machine type. Also, make sure to select the correct network under Add network adapter if there are multiple networks available.
9. Complete the configuration and power on the VM.
Continue to create more compute machines for your cluster.

Disk partitioning

In most cases, data partitions are originally created by installing RHCOS, rather than by installing another operating system. In such cases, the OpenShift Container Platform installer should be allowed to configure your disk partitions.

However, there are two cases where you might want to intervene to override the default partitioning when installing an OpenShift Container Platform node:

Create separate partitions: For greenfield installations on an empty disk, you might want to add separate storage to a partition. This is officially supported for making /var or a subdirectory of /var, such as /var/lib/etcd, a separate partition, but not both.

Kubernetes supports only two filesystem partitions. If you add more than one partition to the original configuration, Kubernetes cannot monitor all of them.
Retain existing partitions: For a brownfield installation where you are reinstalling OpenShift Container Platform on an existing node and want to retain data partitions installed from your previous operating system, there are both boot arguments and options to coreos-installer that allow you to retain existing data partitions.

Creating a separate `/var` partition

In general, disk partitioning for OpenShift Container Platform should be left to the installer. However, there are cases where you might want to create separate partitions in a part of the filesystem that you expect to grow.

OpenShift Container Platform supports the addition of a single partition to attach storage to either the /var partition or a subdirectory of /var. For example:

/var/lib/containers: Holds container-related content that can grow as more images and containers are added to a system.
/var/lib/etcd: Holds data that you might want to keep separate for purposes such as performance optimization of etcd storage.
/var: Holds data that you might want to keep separate for purposes such as auditing.

Storing the contents of a /var directory separately makes it easier to grow storage for those areas as needed and reinstall OpenShift Container Platform at a later date and keep that data intact. With this method, you will not have to pull all your containers again, nor will you have to copy massive log files when you update systems.

Because /var must be in place before a fresh installation of Red Hat Enterprise Linux CoreOS (RHCOS), the following procedure sets up the separate /var partition by creating a machine config that is inserted during the openshift-install preparation phases of an OpenShift Container Platform installation.

Procedure

Create a directory to hold the OpenShift Container Platform installation files:
```
$ mkdir $HOME/clusterconfig
```

Run openshift-install to create a set of files in the manifest and openshift subdirectories. Answer the system questions as you are prompted:

$ openshift-install create manifests --dir $HOME/clusterconfig
? SSH Public Key ...
$ ls $HOME/clusterconfig/openshift/
99_kubeadmin-password-secret.yaml
99_openshift-cluster-api_master-machines-0.yaml
99_openshift-cluster-api_master-machines-1.yaml
99_openshift-cluster-api_master-machines-2.yaml
...

Create a MachineConfig object and add it to a file in the openshift directory. For example, name the file 98-var-partition.yaml, change the disk device name to the name of the storage device on the worker systems, and set the storage size as appropriate. This example places the /var directory on a separate partition:

apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: 98-var-partition
spec:
  config:
    ignition:
      version: 3.1.0
    storage:
      disks:
      - device: /dev/<device_name> (1)
        partitions:
        - label: var
          startMiB: <partition_start_offset> (2)
          sizeMiB: <partition_size> (3)
      filesystems:
        - device: /dev/disk/by-partlabel/var
          path: /var
          format: xfs
    systemd:
      units:
        - name: var.mount (4)
          enabled: true
          contents: |
            [Unit]
            Before=local-fs.target
            [Mount]
            What=/dev/disk/by-partlabel/var
            Where=/var
            Options=defaults,prjquota (5)
            [Install]
            WantedBy=local-fs.target

1	The storage device name of the disk that you want to partition.
2	When adding a data partition to the boot disk, a minimum value of 25000 mebibytes is recommended. The root file system is automatically resized to fill all available space up to the specified offset. If no value is specified, or if the specified value is smaller than the recommended minimum, the resulting root file system will be too small, and future reinstalls of RHCOS might overwrite the beginning of the data partition.
3	The size of the data partition in mebibytes.
4	The name of the mount unit must match the directory specified in the `Where=` directive. For example, for a filesystem mounted on `/var/lib/containers`, the unit must be named `var-lib-containers.mount`.
5	The `prjquota` mount option must be enabled for filesystems used for container storage.

When creating a separate /var partition, you cannot use different instance types for worker nodes, if the different instance types do not have the same device name.

Run openshift-install again to create Ignition configs from a set of files in the manifest and openshift subdirectories:

$ openshift-install create ignition-configs --dir $HOME/clusterconfig
$ ls $HOME/clusterconfig/
auth  bootstrap.ign  master.ign  metadata.json  worker.ign

Now you can use the Ignition config files as input to the vSphere installation procedures to install Red Hat Enterprise Linux CoreOS (RHCOS) systems.

Creating the cluster

To create the OpenShift Container Platform cluster, you wait for the bootstrap process to complete on the machines that you provisioned by using the Ignition config files that you generated with the installation program.

Prerequisites

Create the required infrastructure for the cluster.
You obtained the installation program and generated the Ignition config files for your cluster.
You used the Ignition config files to create RHCOS machines for your cluster.
Your machines have direct Internet access or have an HTTP or HTTPS proxy available.

Procedure

Monitor the bootstrap process:

$ ./openshift-install --dir <installation_directory> wait-for bootstrap-complete \ (1)
    --log-level=info (2)

1	For `<installation_directory>`, specify the path to the directory that you stored the installation files in.
2	To view different installation details, specify `warn`, `debug`, or `error` instead of `info`.

Example output

INFO Waiting up to 30m0s for the Kubernetes API at https://api.test.example.com:6443...
INFO API v1.19.0 up
INFO Waiting up to 30m0s for bootstrapping to complete...
INFO It is now safe to remove the bootstrap resources

The command succeeds when the Kubernetes API server signals that it has been bootstrapped on the control plane machines.

After bootstrap process is complete, remove the bootstrap machine from the load balancer.

You must remove the bootstrap machine from the load balancer at this point. You can also remove or reformat the machine itself.

Logging in to the cluster by using the CLI

You can log in to your cluster as a default system user by exporting the cluster kubeconfig file. The kubeconfig file contains information about the cluster that is used by the CLI to connect a client to the correct cluster and API server. The file is specific to a cluster and is created during OpenShift Container Platform installation.

Prerequisites

You deployed an OpenShift Container Platform cluster.
You installed the oc CLI.

Procedure

Export the kubeadmin credentials:
```
$ export KUBECONFIG=<installation_directory>/auth/kubeconfig (1)
```
1 For <installation_directory>, specify the path to the directory that you stored the installation files in.
Verify you can run oc commands successfully using the exported configuration:
```
$ oc whoami
```
Example output
```
system:admin
```

Approving the certificate signing requests for your machines

When you add machines to a cluster, two pending certificate signing requests (CSRs) are generated for each machine that you added. You must confirm that these CSRs are approved or, if necessary, approve them yourself. The client requests must be approved first, followed by the server requests.

Prerequisites

You added machines to your cluster.

Procedure

Confirm that the cluster recognizes the machines:
```
$ oc get nodes
```
Example output
```
NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  63m  v1.19.0
master-1  Ready     master  63m  v1.19.0
master-2  Ready     master  64m  v1.19.0
```
The output lists all of the machines that you created.

The preceding output might not include the compute nodes, also known as worker nodes, until some CSRs are approved.

Review the pending CSRs and ensure that you see the client requests with the Pending or Approved status for each machine that you added to the cluster:

$ oc get csr

Example output

NAME        AGE     REQUESTOR                                                                   CONDITION
csr-8b2br   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending
csr-8vnps   15m     system:serviceaccount:openshift-machine-config-operator:node-bootstrapper   Pending
...

In this example, two machines are joining the cluster. You might see more approved CSRs in the list.

If the CSRs were not approved, after all of the pending CSRs for the machines you added are in Pending status, approve the CSRs for your cluster machines:

Because the CSRs rotate automatically, approve your CSRs within an hour of adding the machines to the cluster. If you do not approve them within an hour, the certificates will rotate, and more than two certificates will be present for each node. You must approve all of these certificates. Once the client CSR is approved, the Kubelet creates a secondary CSR for the serving certificate, which requires manual approval. Then, subsequent serving certificate renewal requests are automatically approved by the machine-approver if the Kubelet requests a new certificate with identical parameters.

For clusters running on platforms that are not machine API enabled, such as bare metal and other user-provisioned infrastructure, you must implement a method of automatically approving the kubelet serving certificate requests (CSRs). If a request is not approved, then the oc exec, oc rsh, and oc logs commands cannot succeed, because a serving certificate is required when the API server connects to the kubelet. Any operation that contacts the Kubelet endpoint requires this certificate approval to be in place. The method must watch for new CSRs, confirm that the CSR was submitted by the node-bootstrapper service account in the system:node or system:admin groups, and confirm the identity of the node.

To approve them individually, run the following command for each valid CSR:
```
$ oc adm certificate approve <csr_name> (1)
```
1 <csr_name> is the name of a CSR from the list of current CSRs.

To approve all pending CSRs, run the following command:

$ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs --no-run-if-empty oc adm certificate approve

Some Operators might not become available until some CSRs are approved.

Now that your client requests are approved, you must review the server requests for each machine that you added to the cluster:

$ oc get csr

Example output

NAME        AGE     REQUESTOR                                                                   CONDITION
csr-bfd72   5m26s   system:node:ip-10-0-50-126.us-east-2.compute.internal                       Pending
csr-c57lv   5m26s   system:node:ip-10-0-95-157.us-east-2.compute.internal                       Pending
...

If the remaining CSRs are not approved, and are in the Pending status, approve the CSRs for your cluster machines:
- To approve them individually, run the following command for each valid CSR:
  $ oc adm certificate approve <csr_name> (1)
  1 <csr_name> is the name of a CSR from the list of current CSRs.
- To approve all pending CSRs, run the following command:
  $ oc get csr -o go-template='{{range .items}}{{if not .status}}{{.metadata.name}}{{"\n"}}{{end}}{{end}}' | xargs oc adm certificate approve

After all client and server CSRs have been approved, the machines have the Ready status. Verify this by running the following command:

$ oc get nodes

Example output

NAME      STATUS    ROLES   AGE  VERSION
master-0  Ready     master  73m  v1.20.0
master-1  Ready     master  73m  v1.20.0
master-2  Ready     master  74m  v1.20.0
worker-0  Ready     worker  11m  v1.20.0
worker-1  Ready     worker  11m  v1.20.0

It can take a few minutes after approval of the server CSRs for the machines to transition to the Ready status.

Additional information

For more information on CSRs, see Certificate Signing Requests.

Initial Operator configuration

After the control plane initializes, you must immediately configure some Operators so that they all become available.

Prerequisites

Your control plane has initialized.

Procedure

Watch the cluster components come online:

$ watch -n5 oc get clusteroperators

Example output

NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Configure the Operators that are not available.

Image registry removed during installation

On platforms that do not provide shareable object storage, the OpenShift Image Registry Operator bootstraps itself as Removed. This allows openshift-installer to complete installations on these platform types.

After installation, you must edit the Image Registry Operator configuration to switch the managementState from Removed to Managed.

The Prometheus console provides an ImageRegistryRemoved alert, for example:

"Image Registry has been removed. ImageStreamTags, BuildConfigs and DeploymentConfigs which reference ImageStreamTags may not work as expected. Please configure storage and update the config to Managed state by editing configs.imageregistry.operator.openshift.io."

Image registry storage configuration

The Image Registry Operator is not initially available for platforms that do not provide default storage. After installation, you must configure your registry to use storage so that the Registry Operator is made available.

Instructions are shown for configuring a persistent volume, which is required for production clusters. Where applicable, instructions are shown for configuring an empty directory as the storage location, which is available for only non-production clusters.

Additional instructions are provided for allowing the image registry to use block storage types by using the Recreate rollout strategy during upgrades.

Configuring block registry storage for VMware vSphere

To allow the image registry to use block storage types such as vSphere Virtual Machine Disk (VMDK) during upgrades as a cluster administrator, you can use the Recreate rollout strategy.

Block storage volumes are supported but not recommended for use with image registry on production clusters. An installation where the registry is configured on block storage is not highly available because the registry cannot have more than one replica.

Procedure

To set the image registry storage as a block storage type, patch the registry so that it uses the Recreate rollout strategy and runs with only 1 replica:
```
$ oc patch config.imageregistry.operator.openshift.io/cluster --type=merge -p '{"spec":{"rolloutStrategy":"Recreate","replicas":1}}'
```

Provision the PV for the block storage device, and create a PVC for that volume. The requested block volume uses the ReadWriteOnce (RWO) access mode.

Create a pvc.yaml file with the following contents to define a VMware vSphere PersistentVolumeClaim object:

kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: image-registry-storage (1)
  namespace: openshift-image-registry (2)
spec:
  accessModes:
  - ReadWriteOnce (3)
  resources:
    requests:
      storage: 100Gi (4)

1	A unique name that represents the `PersistentVolumeClaim` object.
2	The namespace for the `PersistentVolumeClaim` object, which is `openshift-image-registry`.
3	The access mode of the persistent volume claim. With `ReadWriteOnce`, the volume can be mounted with read and write permissions by a single node.
4	The size of the persistent volume claim.

Create the PersistentVolumeClaim object from the file:

$ oc create -f pvc.yaml -n openshift-image-registry

Edit the registry configuration so that it references the correct PVC:
```
$ oc edit config.imageregistry.operator.openshift.io -o yaml
```
Example output
```
storage:
  pvc:
    claim: (1)
```
1 Creating a custom PVC allows you to leave the claim field blank for the default automatic creation of an image-registry-storage PVC.

For instructions about configuring registry storage so that it references the correct PVC, see Configuring the registry for vSphere.

Completing installation on user-provisioned infrastructure

After you complete the Operator configuration, you can finish installing the cluster on infrastructure that you provide.

Prerequisites

Your control plane has initialized.
You have completed the initial Operator configuration.

Procedure

Confirm that all the cluster components are online with the following command:

$ watch -n5 oc get clusteroperators

Example output

NAME                                       VERSION AVAILABLE   PROGRESSING   DEGRADED   SINCE
authentication                             4.6.0   True        False         False      3h56m
cloud-credential                           4.6.0   True        False         False      29h
cluster-autoscaler                         4.6.0   True        False         False      29h
config-operator                            4.6.0   True        False         False      6h39m
console                                    4.6.0   True        False         False      3h59m
csi-snapshot-controller                    4.6.0   True        False         False      4h12m
dns                                        4.6.0   True        False         False      4h15m
etcd                                       4.6.0   True        False         False      29h
image-registry                             4.6.0   True        False         False      3h59m
ingress                                    4.6.0   True        False         False      4h30m
insights                                   4.6.0   True        False         False      29h
kube-apiserver                             4.6.0   True        False         False      29h
kube-controller-manager                    4.6.0   True        False         False      29h
kube-scheduler                             4.6.0   True        False         False      29h
kube-storage-version-migrator              4.6.0   True        False         False      4h2m
machine-api                                4.6.0   True        False         False      29h
machine-approver                           4.6.0   True        False         False      6h34m
machine-config                             4.6.0   True        False         False      3h56m
marketplace                                4.6.0   True        False         False      4h2m
monitoring                                 4.6.0   True        False         False      6h31m
network                                    4.6.0   True        False         False      29h
node-tuning                                4.6.0   True        False         False      4h30m
openshift-apiserver                        4.6.0   True        False         False      3h56m
openshift-controller-manager               4.6.0   True        False         False      4h36m
openshift-samples                          4.6.0   True        False         False      4h30m
operator-lifecycle-manager                 4.6.0   True        False         False      29h
operator-lifecycle-manager-catalog         4.6.0   True        False         False      29h
operator-lifecycle-manager-packageserver   4.6.0   True        False         False      3h59m
service-ca                                 4.6.0   True        False         False      29h
storage                                    4.6.0   True        False         False      4h30m

Alternatively, the following command notifies you when all of the clusters are available. It also retrieves and displays credentials:

$ ./openshift-install --dir <installation_directory> wait-for install-complete (1)

1	For `<installation_directory>`, specify the path to the directory that you stored the installation files in.

Example output

INFO Waiting up to 30m0s for the cluster to initialize...

The command succeeds when the Cluster Version Operator finishes deploying the OpenShift Container Platform cluster from Kubernetes API server.

The Ignition config files that the installation program generates contain certificates that expire after 24 hours, which are then renewed at that time. If the cluster is shut down before renewing the certificates and the cluster is later restarted after the 24 hours have elapsed, the cluster automatically recovers the expired certificates. The exception is that you must manually approve the pending node-bootstrapper certificate signing requests (CSRs) to recover kubelet certificates. See the documentation for Recovering from expired control plane certificates for more information.
It is recommended that you use Ignition config files within 12 hours after they are generated because the 24-hour certificate rotates from 16 to 22 hours after the cluster is installed. By using the Ignition config files within 12 hours, you can avoid installation failure if the certificate update runs during installation.

Confirm that the Kubernetes API server is communicating with the pods.

To view a list of all pods, use the following command:

$ oc get pods --all-namespaces

Example output

NAMESPACE                         NAME                                            READY   STATUS      RESTARTS   AGE
openshift-apiserver-operator      openshift-apiserver-operator-85cb746d55-zqhs8   1/1     Running     1          9m
openshift-apiserver               apiserver-67b9g                                 1/1     Running     0          3m
openshift-apiserver               apiserver-ljcmx                                 1/1     Running     0          1m
openshift-apiserver               apiserver-z25h4                                 1/1     Running     0          2m
openshift-authentication-operator authentication-operator-69d5d8bf84-vh2n8        1/1     Running     0          5m
...

View the logs for a pod that is listed in the output of the previous command by using the following command:
```
$ oc logs <pod_name> -n <namespace> (1)
```
1 Specify the pod name and namespace, as shown in the output of the previous command.

If the pod logs display, the Kubernetes API server can communicate with the cluster machines.

You can add extra compute machines after the cluster installation is completed by following Adding compute machines to vSphere.

Backing up VMware vSphere volumes

OpenShift Container Platform provisions new volumes as independent persistent disks to freely attach and detach the volume on any node in the cluster. As a consequence, it is not possible to back up volumes that use snapshots, or to restore volumes from snapshots. See Snapshot Limitations for more information.

Procedure

To create a backup of persistent volumes:

Stop the application that is using the persistent volume.
Clone the persistent volume.
Restart the application.
Create a backup of the cloned volume.
Delete the cloned volume.

Telemetry access for OpenShift Container Platform

In OpenShift Container Platform 4.6, the Telemetry service, which runs by default to provide metrics about cluster health and the success of updates, requires internet access. If your cluster is connected to the internet, Telemetry runs automatically, and your cluster is registered to OpenShift Cluster Manager.

After you confirm that your OpenShift Cluster Manager inventory is correct, either maintained automatically by Telemetry or manually by using OpenShift Cluster Manager, use subscription watch to track your OpenShift Container Platform subscriptions at the account or multi-cluster level.

Additional resources

See About remote health monitoring for more information about the Telemetry service

Next steps

Customize your cluster.
If necessary, you can opt out of remote health reporting.
Set up your registry and configure registry storage.

Setting up VMC for vSphere

VMC Sizer tool

vSphere prerequisites

Internet access for OpenShift Container Platform

VMware vSphere infrastructure requirements

Machine requirements for a cluster with user-provisioned infrastructure

Required machines

Network connectivity requirements

Minimum resource requirements

Certificate signing requests management

Creating the user-provisioned infrastructure

Networking requirements for user-provisioned infrastructure

Network topology requirements

Load balancers

NTP configuration

User-provisioned DNS requirements

Generating an SSH private key and adding it to the agent

Obtaining the installation program

Manually creating the installation configuration file

Sample install-config.yaml file for VMware vSphere

Configuring the cluster-wide proxy during installation

Specifying advanced network configuration

Cluster Network Operator configuration

Cluster Network Operator configuration object

defaultNetwork object configuration

Configuration for the OpenShift SDN CNI cluster network provider

Configuration for the OVN-Kubernetes CNI cluster network provider

kubeProxyConfig object configuration

Creating the Ignition config files

Extracting the infrastructure name

Creating Red Hat Enterprise Linux CoreOS (RHCOS) machines in vSphere

Creating more Red Hat Enterprise Linux CoreOS (RHCOS) machines in vSphere

Disk partitioning

Creating a separate /var partition

Creating the cluster

Logging in to the cluster by using the CLI

Approving the certificate signing requests for your machines

Initial Operator configuration

Image registry removed during installation

Image registry storage configuration

Configuring block registry storage for VMware vSphere

Completing installation on user-provisioned infrastructure

Backing up VMware vSphere volumes

Telemetry access for OpenShift Container Platform

Next steps

Sample `install-config.yaml` file for VMware vSphere

Creating a separate `/var` partition