Installing a cluster on Alibaba Cloud with customizations - Installing on Alibaba | Installing

Prerequisites
Generating a key pair for cluster node SSH access
Obtaining the installation program

In OKD version 4.11, you can install a customized cluster on infrastructure that the installation program provisions on Alibaba Cloud. To customize the installation, you modify parameters in the install-config.yaml file before you install the cluster.

The scope of the OKD installation configurations is intentionally narrow. It is designed for simplicity and ensured success. You can complete many more OKD configuration tasks after an installation completes.

Alibaba Cloud on OKD is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.

For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.

Prerequisites

You reviewed details about the OKD installation and update processes.
You read the documentation on selecting a cluster installation method and preparing it for users.
You registered your domain.
If you use a firewall, you configured it to allow the sites that your cluster requires access to.
If the cloud Resource Access Management (RAM) APIs are not accessible in your environment, or if you do not want to store an administrator-level credential secret in the kube-system namespace, you can manually create and maintain Resource Access Management (RAM) credentials.

Generating a key pair for cluster node SSH access

During an OKD installation, you can provide an SSH public key to the installation program. The key is passed to the Fedora CoreOS (FCOS) nodes through their Ignition config files and is used to authenticate SSH access to the nodes. The key is added to the ~/.ssh/authorized_keys list for the core user on each node, which enables password-less authentication.

After the key is passed to the nodes, you can use the key pair to SSH in to the FCOS nodes as the user core. To access the nodes through SSH, the private key identity must be managed by SSH for your local user.

If you want to SSH in to your cluster nodes to perform installation debugging or disaster recovery, you must provide the SSH public key during the installation process. The ./openshift-install gather command also requires the SSH public key to be in place on the cluster nodes.

Do not skip this procedure in production environments, where disaster recovery and debugging is required.

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

On clusters running Fedora CoreOS (FCOS), the SSH keys specified in the Ignition config files are written to the /home/core/.ssh/authorized_keys.d/core file. However, the Machine Config Operator manages SSH keys in the /home/core/.ssh/authorized_keys file and configures sshd to ignore the /home/core/.ssh/authorized_keys.d/core file. As a result, newly provisioned OKD nodes are not accessible using SSH until the Machine Config Operator reconciles the machine configs with the authorized_keys file. After you can access the nodes using SSH, you can delete the /home/core/.ssh/authorized_keys.d/core file.

Procedure

If you do not have an existing SSH key pair on your local machine to use for authentication onto your cluster nodes, 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_ed25519`, of the new SSH key. If you have an existing key pair, ensure your public key is in the your `~/.ssh` directory.

If you plan to install an OKD cluster that uses fips validated or 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.

View the public SSH key:
```
$ cat <path>/<file_name>.pub
```
For example, run the following to view the ~/.ssh/id_ed25519.pub public key:
```
$ cat ~/.ssh/id_ed25519.pub
```
Add the SSH private key identity to the SSH agent for your local user, if it has not already been added. SSH agent management of the key is required for password-less SSH authentication onto your cluster nodes, or if you want to use the ./openshift-install gather command.

On some distributions, default SSH private key identities such as ~/.ssh/id_rsa and ~/.ssh/id_dsa are managed automatically.
1. If the ssh-agent process is not already running for your local user, start it 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)
```
1 Specify the path and file name for your SSH private key, such as ~/.ssh/id_ed25519
Example output
```
Identity added: /home/<you>/<path>/<file_name> (<computer_name>)
```

Next steps

When you install OKD, provide the SSH public key to the installation program.

Obtaining the installation program

Before you install OKD, 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

Download installer from https://github.com/openshift/okd/releases

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 OKD 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 OKD components.

Using a pull secret from the Red Hat OpenShift Cluster Manager is not required. You can use a pull secret for another private registry. Or, if you do not need the cluster to pull images from a private registry, you can use {"auths":{"fake":{"auth":"aWQ6cGFzcwo="}}} as the pull secret when prompted during the installation.

If you do not use the pull secret from the Red Hat OpenShift Cluster Manager:
- Red Hat Operators are not available.
- The Telemetry and Insights operators do not send data to Red Hat.
- Content from the Red Hat Container Catalog registry, such as image streams and Operators, are not available.

Creating the installation configuration file

You can customize the OKD cluster you install on Alibaba Cloud.

Prerequisites

Obtain the OKD installation program and the pull secret for your cluster.
Obtain service principal permissions at the subscription level.

Procedure

Create the install-config.yaml file.
1. Change to the directory that contains the installation program and run the following command:
  $ ./openshift-install create install-config --dir <installation_directory> (1)
  1 For <installation_directory>, specify the directory name to store the files that the installation program creates.
  
  When specifying the directory:
  - Verify that the directory has the execute permission. This permission is required to run Terraform binaries under the installation directory.
  - Use an empty directory. Some installation assets, such as bootstrap X.509 certificates, have short expiration intervals, therefore 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 OKD version.
2. At the prompts, provide the configuration details for your cloud:
  1. Optional: Select an SSH key to use to access your cluster machines.
    
    For production OKD clusters on which you want to perform installation debugging or disaster recovery, specify an SSH key that your ssh-agent process uses.
  2. Select alibabacloud as the platform to target.
  3. Select the region to deploy the cluster to.
  4. Select the base domain to deploy the cluster to. The base domain corresponds to the public DNS zone that you created for your cluster.
  5. Provide a descriptive name for your cluster.
  6. Paste the pull secret from the Red Hat OpenShift Cluster Manager. This field is optional.
Installing the cluster into Alibaba Cloud requires that the Cloud Credential Operator (CCO) operate in manual mode. Modify the install-config.yaml file to set the credentialsMode parameter to Manual:
Example install-config.yaml configuration file with credentialsMode set to Manual
```
apiVersion: v1
baseDomain: cluster1.example.com
credentialsMode: Manual (1)
compute:
- architecture: amd64
  hyperthreading: Enabled
 ...
```
1 Add this line to set the credentialsMode to Manual.
Modify the install-config.yaml file. You can find more information about the available parameters in the "Installation configuration parameters" section.
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 installation process. If you want to reuse the file, you must back it up now.

Generating the required installation manifests

You must generate the Kubernetes manifest and Ignition config files that the cluster needs to configure the machines.

Procedure

Generate the manifests by running the following command from the directory that contains the installation program:
```
$ openshift-install create manifests --dir <installation_directory>
```
where:

<installation_directory>

Specifies the directory in which the installation program creates files.

Creating credentials for OKD components with the ccoctl tool

You can use the OKD Cloud Credential Operator (CCO) utility to automate the creation of Alibaba Cloud RAM users and policies for each in-cluster component.

By default, ccoctl creates objects in the directory in which the commands are run. To create the objects in a different directory, use the --output-dir flag. This procedure uses <path_to_ccoctl_output_dir> to refer to this directory.

Prerequisites

You must have:

Extracted and prepared the ccoctl binary.
Created a RAM user with sufficient permission to create the OKD cluster.
Added the AccessKeyID (access_key_id) and AccessKeySecret (access_key_secret) of that RAM user into the ~/.alibabacloud/credentials file on your local computer.

Procedure

Set the $RELEASE_IMAGE variable by running the following command:

$ RELEASE_IMAGE=$(./openshift-install version | awk '/release image/ {print $3}')

Extract the list of CredentialsRequest objects from the OKD release image by running the following command:
```
$ oc adm release extract \
--credentials-requests \
--cloud=alibabacloud \
--to=<path_to_directory_with_list_of_credentials_requests>/credrequests \ (1)
$RELEASE_IMAGE
```
1 credrequests is the directory where the list of CredentialsRequest objects is stored. This command creates the directory if it does not exist.

This command can take a few moments to run.

If your cluster uses cluster capabilities to disable one or more optional components, delete the CredentialsRequest custom resources for any disabled components.

Example credrequests directory contents for OKD 4.12 on Alibaba Cloud

0000_30_machine-api-operator_00_credentials-request.yaml (1)
0000_50_cluster-image-registry-operator_01-registry-credentials-request-alibaba.yaml (2)
0000_50_cluster-ingress-operator_00-ingress-credentials-request.yaml (3)
0000_50_cluster-storage-operator_03_credentials_request_alibaba.yaml (4)

1	The Machine API Operator CR is required.
2	The Image Registry Operator CR is required.
3	The Ingress Operator CR is required.
4	The Storage Operator CR is an optional component and might be disabled in your cluster.

Use the ccoctl tool to process all CredentialsRequest objects in the credrequests directory:

Run the following command to use the tool:

$ ccoctl alibabacloud create-ram-users \
--name <name> \
--region=<alibaba_region> \
--credentials-requests-dir=<path_to_directory_with_list_of_credentials_requests>/credrequests \
--output-dir=<path_to_ccoctl_output_dir>

where:

<name> is the name used to tag any cloud resources that are created for tracking.
<alibaba_region> is the Alibaba Cloud region in which cloud resources will be created.
<path_to_directory_with_list_of_credentials_requests>/credrequests is the directory containing the files for the component CredentialsRequest objects.
<path_to_ccoctl_output_dir> is the directory where the generated component credentials secrets will be placed.

If your cluster uses Technology Preview features that are enabled by the TechPreviewNoUpgrade feature set, you must include the --enable-tech-preview parameter.

Example output

2022/02/11 16:18:26 Created RAM User: user1-alicloud-openshift-machine-api-alibabacloud-credentials
2022/02/11 16:18:27 Ready for creating new ram policy user1-alicloud-openshift-machine-api-alibabacloud-credentials-policy-policy
2022/02/11 16:18:27 RAM policy user1-alicloud-openshift-machine-api-alibabacloud-credentials-policy-policy has created
2022/02/11 16:18:28 Policy user1-alicloud-openshift-machine-api-alibabacloud-credentials-policy-policy has attached on user user1-alicloud-openshift-machine-api-alibabacloud-credentials
2022/02/11 16:18:29 Created access keys for RAM User: user1-alicloud-openshift-machine-api-alibabacloud-credentials
2022/02/11 16:18:29 Saved credentials configuration to: user1-alicloud/manifests/openshift-machine-api-alibabacloud-credentials-credentials.yaml
...

A RAM user can have up to two AccessKeys at the same time. If you run ccoctl alibabacloud create-ram-users more than twice, the previous generated manifests secret becomes stale and you must reapply the newly generated secrets.

Verify that the OKD secrets are created:

$ ls <path_to_ccoctl_output_dir>/manifests

Example output:

openshift-cluster-csi-drivers-alibaba-disk-credentials-credentials.yaml
openshift-image-registry-installer-cloud-credentials-credentials.yaml
openshift-ingress-operator-cloud-credentials-credentials.yaml
openshift-machine-api-alibabacloud-credentials-credentials.yaml

You can verify that the RAM users and policies are created by querying Alibaba Cloud. For more information, refer to Alibaba Cloud documentation on listing RAM users and policies.

Copy the generated credential files to the target manifests directory:
```
$ cp ./<path_to_ccoctl_output_dir>/manifests/*credentials.yaml ./<path_to_installation>dir>/manifests/
```
where:

<path_to_ccoctl_output_dir>

Specifies the directory created by the ccoctl alibabacloud create-ram-users command.

<path_to_installation_dir>

Specifies the directory in which the installation program creates files.

Installation configuration parameters

Before you deploy an OKD cluster, you provide parameter values to describe your account on the cloud platform that hosts your cluster and optionally customize your cluster’s platform. When you create the install-config.yaml installation configuration file, you provide values for the required parameters through the command line. If you customize your cluster, you can modify the install-config.yaml file to provide more details about the platform.

After installation, you cannot modify these parameters in the install-config.yaml file.

Required configuration parameters

Required installation configuration parameters are described in the following table:

Table 1. Required parameters
Parameter	Description	Values
`apiVersion`	The API version for the `install-config.yaml` content. The current version is `v1`. The installer may also support older API versions.	String
`baseDomain`	The base domain of your cloud provider. The base domain is used to create routes to your OKD cluster components. The full DNS name for your cluster is a combination of the `baseDomain` and `metadata.name` parameter values that uses the `<metadata.name>.<baseDomain>` format.	A fully-qualified domain or subdomain name, such as `example.com`.
`metadata`	Kubernetes resource `ObjectMeta`, from which only the `name` parameter is consumed.	Object
`metadata.name`	The name of the cluster. DNS records for the cluster are all subdomains of `{{.metadata.name}}.{{.baseDomain}}`.	String of lowercase letters, hyphens (`-`), and periods (`.`), such as `dev`.
`platform`	The configuration for the specific platform upon which to perform the installation: `alibabacloud`, `aws`, `baremetal`, `azure`, `gcp`, `ibmcloud`, `nutanix`, `openstack`, `ovirt`, `vsphere`, or `{}`. For additional information about `platform.<platform>` parameters, consult the table for your specific platform that follows.	Object

Network configuration parameters

You can customize your installation configuration based on the requirements of your existing network infrastructure. For example, you can expand the IP address block for the cluster network or provide different IP address blocks than the defaults.

Only IPv4 addresses are supported.

Globalnet is not supported with Red Hat OpenShift Data Foundation disaster recovery solutions. For regional disaster recovery scenarios, ensure that you use a nonoverlapping range of private IP addresses for the cluster and service networks in each cluster.

Parameter Description Values

networking

The configuration for the cluster network.

Object

You cannot modify parameters specified by the networking object after installation.

networking.networkType

The cluster network provider Container Network Interface (CNI) cluster network provider to install.

Either OpenShiftSDN or OVNKubernetes. The default value is OVNKubernetes.

networking.clusterNetwork

The IP address blocks for pods.

The default value is 10.128.0.0/14 with a host prefix of /23.

If you specify multiple IP address blocks, the blocks must not overlap.

An array of objects. For example:

networking:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23

networking.clusterNetwork.cidr

Required if you use networking.clusterNetwork. An IP address block.

An IPv4 network.

An IP address block in Classless Inter-Domain Routing (CIDR) notation. The prefix length for an IPv4 block is between 0 and 32.

networking.clusterNetwork.hostPrefix

The subnet prefix length to assign to each individual node. For example, if hostPrefix is set to 23 then each node is assigned a /23 subnet out of the given cidr. A hostPrefix value of 23 provides 510 (2^(32 - 23) - 2) pod IP addresses.

A subnet prefix.

The default value is 23.

networking.serviceNetwork

The IP address block for services. The default value is 172.30.0.0/16.

The OpenShift SDN and OVN-Kubernetes network providers support only a single IP address block for the service network.

An array with an IP address block in CIDR format. For example:

networking:
  serviceNetwork:
   - 172.30.0.0/16

networking.machineNetwork

The IP address blocks for machines.

If you specify multiple IP address blocks, the blocks must not overlap.

An array of objects. For example:

networking:
  machineNetwork:
  - cidr: 10.0.0.0/16

networking.machineNetwork.cidr

Required if you use networking.machineNetwork. An IP address block. The default value is 10.0.0.0/16 for all platforms other than libvirt. For libvirt, the default value is 192.168.126.0/24.

An IP network block in CIDR notation.

For example, 10.0.0.0/16.

Set the networking.machineNetwork to match the CIDR that the preferred NIC resides in.

Optional configuration parameters

Optional installation configuration parameters are described in the following table:

Parameter Description Values

additionalTrustBundle

A PEM-encoded X.509 certificate bundle that is added to the nodes' trusted certificate store. This trust bundle may also be used when a proxy has been configured.

String

capabilities

Controls the installation of optional core cluster components. You can reduce the footprint of your OKD cluster by disabling optional components.

String array

capabilities.baselineCapabilitySet

Selects an initial set of optional capabilities to enable. Valid values are None, v4.11 and vCurrent. v4.11 enables the baremetal Operator, the marketplace Operator, and the openshift-samples content. vCurrent installs the recommended set of capabilities for the current version of OKD. The default value is vCurrent.

String

capabilities.additionalEnabledCapabilities

Extends the set of optional capabilities beyond what you specify in baselineCapabilitySet. Valid values are baremetal, marketplace and openshift-samples. You may specify multiple capabilities in this parameter.

String array

cgroupsV2

Enables Linux control groups version 2 (cgroups v2) on specific nodes in your cluster. The OKD process for enabling cgroups v2 disables all cgroup version 1 controllers and hierarchies. The OKD cgroups version 2 feature is in Developer Preview and is not supported by Red Hat at this time.

true

compute

The configuration for the machines that comprise the compute nodes.

Array of MachinePool objects.

compute.architecture

Determines the instruction set architecture of the machines in the pool. Currently, clusters with varied architectures are not supported. All pools must specify the same architecture. Valid values are amd64 (the default).

String

compute.hyperthreading

Whether to enable or disable simultaneous multithreading, or hyperthreading, on compute machines. By default, simultaneous multithreading is enabled to increase the performance of your machines' cores.

If you disable simultaneous multithreading, ensure that your capacity planning accounts for the dramatically decreased machine performance.

Enabled or Disabled

compute.name

Required if you use compute. The name of the machine pool.

worker

compute.platform

Required if you use compute. Use this parameter to specify the cloud provider to host the worker machines. This parameter value must match the controlPlane.platform parameter value.

alibabacloud, aws, azure, gcp, ibmcloud, nutanix, openstack, ovirt, vsphere, or {}

compute.replicas

The number of compute machines, which are also known as worker machines, to provision.

A positive integer greater than or equal to 2. The default value is 3.

controlPlane

The configuration for the machines that comprise the control plane.

Array of MachinePool objects.

controlPlane.architecture

String