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Network configuration | Post-installation configuration | OKD 4.9
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Post-installation network configuration

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.

After cluster installation, you cannot modify the fields listed in the previous section.

Enabling the cluster-wide proxy

The Proxy object is used to manage the cluster-wide egress proxy. When a cluster is installed or upgraded without the proxy configured, a Proxy object is still generated but it will have a nil spec. For example:

apiVersion: config.openshift.io/v1
kind: Proxy
metadata:
  name: cluster
spec:
  trustedCA:
    name: ""
status:

A cluster administrator can configure the proxy for OKD by modifying this cluster Proxy object.

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

  • Cluster administrator permissions

  • OKD oc CLI tool installed

Procedure

  1. Create a config map that contains any additional CA certificates required for proxying HTTPS connections.

    You can skip this step if the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle.

    1. Create a file called user-ca-bundle.yaml with the following contents, and provide the values of your PEM-encoded certificates:

      apiVersion: v1
data:
  ca-bundle.crt: | (1)
    <MY_PEM_ENCODED_CERTS> (2)
kind: ConfigMap
metadata:
  name: user-ca-bundle (3)
  namespace: openshift-config (4)
      1 This data key must be named ca-bundle.crt.
      2 One or more PEM-encoded X.509 certificates used to sign the proxy’s identity certificate.
      3 The config map name that will be referenced from the Proxy object.
      4 The config map must be in the openshift-config namespace.

    2. Create the config map from this file:

      $ oc create -f user-ca-bundle.yaml

  2. Use the oc edit command to modify the Proxy object:

    $ oc edit proxy/cluster

  3. Configure the necessary fields for the proxy:

    apiVersion: config.openshift.io/v1
kind: Proxy
metadata:
  name: cluster
spec:
  httpProxy: http://<username>:<pswd>@<ip>:<port> (1)
  httpsProxy: https://<username>:<pswd>@<ip>:<port> (2)
  noProxy: example.com (3)
  readinessEndpoints:
  - http://www.google.com (4)
  - https://www.google.com
  trustedCA:
    name: user-ca-bundle (5)
    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. The URL scheme must be either http or https. Specify a URL for the proxy that supports the URL scheme. For example, most proxies will report an error if they are configured to use https but they only support http. This failure message may not propagate to the logs and can appear to be a network connection failure instead. If using a proxy that listens for https connections from the cluster, you may need to configure the cluster to accept the CAs and certificates that the proxy uses.
    3 A comma-separated list of destination domain names, domains, IP addresses or other network CIDRs to exclude proxying.

    Preface a domain with . to match subdomains only. For example, .y.com matches x.y.com, but not y.com. Use * to bypass proxy for all destinations. If you scale up workers that are not included in the network defined by the networking.machineNetwork[].cidr field from the installation configuration, you must add them to this list to prevent connection issues.

    This field is ignored if neither the httpProxy or httpsProxy fields are set.
    4 One or more URLs external to the cluster to use to perform a readiness check before writing the httpProxy and httpsProxy values to status.
    5 A reference to the config map in the openshift-config namespace that contains additional CA certificates required for proxying HTTPS connections. Note that the config map must already exist before referencing it here. This field is required unless the proxy’s identity certificate is signed by an authority from the RHCOS trust bundle.

  4. Save the file to apply the changes.

Setting DNS to private

After you deploy a cluster, you can modify its DNS to use only a private zone.

Procedure

  1. Review the DNS custom resource for your cluster:

    $ oc get dnses.config.openshift.io/cluster -o yaml
    Example output
    apiVersion: config.openshift.io/v1
kind: DNS
metadata:
  creationTimestamp: "2019-10-25T18:27:09Z"
  generation: 2
  name: cluster
  resourceVersion: "37966"
  selfLink: /apis/config.openshift.io/v1/dnses/cluster
  uid: 0e714746-f755-11f9-9cb1-02ff55d8f976
spec:
  baseDomain: <base_domain>
  privateZone:
    tags:
      Name: <infrastructure_id>-int
      kubernetes.io/cluster/<infrastructure_id>: owned
  publicZone:
    id: Z2XXXXXXXXXXA4
status: {}

    Note that the spec section contains both a private and a public zone.

  2. Patch the DNS custom resource to remove the public zone:

    $ oc patch dnses.config.openshift.io/cluster --type=merge --patch='{"spec": {"publicZone": null}}'
dns.config.openshift.io/cluster patched

    Because the Ingress Controller consults the DNS definition when it creates Ingress objects, when you create or modify Ingress objects, only private records are created.

    DNS records for the existing Ingress objects are not modified when you remove the public zone.

  3. Optional: Review the DNS custom resource for your cluster and confirm that the public zone was removed:

    $ oc get dnses.config.openshift.io/cluster -o yaml
    Example output
    apiVersion: config.openshift.io/v1
kind: DNS
metadata:
  creationTimestamp: "2019-10-25T18:27:09Z"
  generation: 2
  name: cluster
  resourceVersion: "37966"
  selfLink: /apis/config.openshift.io/v1/dnses/cluster
  uid: 0e714746-f755-11f9-9cb1-02ff55d8f976
spec:
  baseDomain: <base_domain>
  privateZone:
    tags:
      Name: <infrastructure_id>-int
      kubernetes.io/cluster/<infrastructure_id>-wfpg4: owned
status: {}

Configuring ingress cluster traffic

OKD provides the following methods for communicating from outside the cluster with services running in the cluster:

  • If you have HTTP/HTTPS, use an Ingress Controller.

  • If you have a TLS-encrypted protocol other than HTTPS, such as TLS with the SNI header, use an Ingress Controller.

  • Otherwise, use a load balancer, an external IP, or a node port.

Method Purpose

Use an Ingress Controller

Allows access to HTTP/HTTPS traffic and TLS-encrypted protocols other than HTTPS, such as TLS with the SNI header.

Automatically assign an external IP by using a load balancer service

Allows traffic to non-standard ports through an IP address assigned from a pool.

Manually assign an external IP to a service

Allows traffic to non-standard ports through a specific IP address.

Configure a NodePort

Expose a service on all nodes in the cluster.

Configuring the node port service range

As a cluster administrator, you can expand the available node port range. If your cluster uses of a large number of node ports, you might need to increase the number of available ports.

The default port range is 30000-32767. You can never reduce the port range, even if you first expand it beyond the default range.

Prerequisites

  • Your cluster infrastructure must allow access to the ports that you specify within the expanded range. For example, if you expand the node port range to 30000-32900, the inclusive port range of 32768-32900 must be allowed by your firewall or packet filtering configuration.

Expanding the node port range

You can expand the node port range for the cluster.

Prerequisites

  • Install the OpenShift CLI (oc).

  • Log in to the cluster with a user with cluster-admin privileges.

Procedure

  1. To expand the node port range, enter the following command. Replace <port> with the largest port number in the new range.

    $ oc patch network.config.openshift.io cluster --type=merge -p \
  '{
    "spec":
      { "serviceNodePortRange": "30000-<port>" }
  }'

    You can alternatively apply the following YAML to update the node port range:

    apiVersion: config.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  serviceNodePortRange: "30000-<port>"
    Example output
    network.config.openshift.io/cluster patched

  2. To confirm that the configuration is active, enter the following command. It can take several minutes for the update to apply.

    $ oc get configmaps -n openshift-kube-apiserver config \
  -o jsonpath="{.data['config\.yaml']}" | \
  grep -Eo '"service-node-port-range":["[[:digit:]]+-[[:digit:]]+"]'
    Example output
    "service-node-port-range":["30000-33000"]

Configuring network policy

As a cluster administrator or project administrator, you can configure network policies for a project.

About network policy

In a cluster using a Kubernetes Container Network Interface (CNI) plugin that supports Kubernetes network policy, network isolation is controlled entirely by NetworkPolicy objects. In OKD 4.9, OpenShift SDN supports using network policy in its default network isolation mode.

When using the OpenShift SDN cluster network provider, the following limitations apply regarding network policies:

  • Network policy egress as specified by the egress field is not supported. Egress firewall is also known as egress network policy in OpenShift SDN. This is not the same as network policy egress.

  • IPBlock is supported by network policy, but without support for except clauses. If you create a policy with an IPBlock section that includes an except clause, the SDN pods log warnings and the entire IPBlock section of that policy is ignored.

Network policy does not apply to the host network namespace. Pods with host networking enabled are unaffected by network policy rules.

By default, all pods in a project are accessible from other pods and network endpoints. To isolate one or more pods in a project, you can create NetworkPolicy objects in that project to indicate the allowed incoming connections. Project administrators can create and delete NetworkPolicy objects within their own project.

If a pod is matched by selectors in one or more NetworkPolicy objects, then the pod will accept only connections that are allowed by at least one of those NetworkPolicy objects. A pod that is not selected by any NetworkPolicy objects is fully accessible.

The following example NetworkPolicy objects demonstrate supporting different scenarios:

  • Deny all traffic:

    To make a project deny by default, add a NetworkPolicy object that matches all pods but accepts no traffic:

    kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: deny-by-default
spec:
  podSelector: {}
  ingress: []

  • Only allow connections from the OKD Ingress Controller:

    To make a project allow only connections from the OKD Ingress Controller, add the following NetworkPolicy object.

    apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-from-openshift-ingress
spec:
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          network.openshift.io/policy-group: ingress
  podSelector: {}
  policyTypes:
  - Ingress

  • Only accept connections from pods within a project:

    To make pods accept connections from other pods in the same project, but reject all other connections from pods in other projects, add the following NetworkPolicy object:

    kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-same-namespace
spec:
  podSelector: {}
  ingress:
  - from:
    - podSelector: {}

  • Only allow HTTP and HTTPS traffic based on pod labels:

    To enable only HTTP and HTTPS access to the pods with a specific label (role=frontend in following example), add a NetworkPolicy object similar to the following:

    kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-http-and-https
spec:
  podSelector:
    matchLabels:
      role: frontend
  ingress:
  - ports:
    - protocol: TCP
      port: 80
    - protocol: TCP
      port: 443

  • Accept connections by using both namespace and pod selectors:

    To match network traffic by combining namespace and pod selectors, you can use a NetworkPolicy object similar to the following:

    kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-pod-and-namespace-both
spec:
  podSelector:
    matchLabels:
      name: test-pods
  ingress:
    - from:
      - namespaceSelector:
          matchLabels:
            project: project_name
        podSelector:
          matchLabels:
            name: test-pods

NetworkPolicy objects are additive, which means you can combine multiple NetworkPolicy objects together to satisfy complex network requirements.

For example, for the NetworkPolicy objects defined in previous samples, you can define both allow-same-namespace and allow-http-and-https policies within the same project. Thus allowing the pods with the label role=frontend, to accept any connection allowed by each policy. That is, connections on any port from pods in the same namespace, and connections on ports 80 and 443 from pods in any namespace.

Example NetworkPolicy object

The following annotates an example NetworkPolicy object:

kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-27107 (1)
spec:
  podSelector: (2)
    matchLabels:
      app: mongodb
  ingress:
  - from:
    - podSelector: (3)
        matchLabels:
          app: app
    ports: (4)
    - protocol: TCP
      port: 27017
1 The name of the NetworkPolicy object.
2 A selector that describes the pods to which the policy applies. The policy object can only select pods in the project that defines the NetworkPolicy object.
3 A selector that matches the pods from which the policy object allows ingress traffic. The selector matches pods in the same namespace as the NetworkPolicy.
4 A list of one or more destination ports on which to accept traffic.

Creating a network policy

To define granular rules describing ingress or egress network traffic allowed for namespaces in your cluster, you can create a network policy.

If you log in with a user with the cluster-admin role, then you can create a network policy in any namespace in the cluster.
Prerequisites

  • Your cluster uses a cluster network provider that supports NetworkPolicy objects, such as the OVN-Kubernetes network provider or the OpenShift SDN network provider with mode: NetworkPolicy set. This mode is the default for OpenShift SDN.

  • You installed the OpenShift CLI (oc).

  • You are logged in to the cluster with a user with admin privileges.

  • You are working in the namespace that the network policy applies to.

Procedure

  1. Create a policy rule:

    1. Create a <policy_name>.yaml file:

      $ touch <policy_name>.yaml

      where:

      <policy_name>

      Specifies the network policy file name.

    2. Define a network policy in the file that you just created, such as in the following examples:

      Deny ingress from all pods in all namespaces
      kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: deny-by-default
spec:
  podSelector:
  ingress: []
    Allow ingress from all pods in the same namespace
    kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-same-namespace
spec:
  podSelector:
  ingress:
  - from:
    - podSelector: {}

  2. To create the network policy object, enter the following command:

    $ oc apply -f <policy_name>.yaml -n <namespace>

    where:

    <policy_name>

    Specifies the network policy file name.

    <namespace>

    Optional: Specifies the namespace if the object is defined in a different namespace than the current namespace.

    Example output
    networkpolicy.networking.k8s.io/default-deny created

If you log in with a user with the cluster-admin role in the console, then you have a choice of creating a network policy in any namespace in the cluster directly from the YAML view or from a form in the web console.

Configuring multitenant isolation by using network policy

You can configure your project to isolate it from pods and services in other project namespaces.

Prerequisites

  • Your cluster uses a cluster network provider that supports NetworkPolicy objects, such as the OVN-Kubernetes network provider or the OpenShift SDN network provider with mode: NetworkPolicy set. This mode is the default for OpenShift SDN.

  • You installed the OpenShift CLI (oc).

  • You are logged in to the cluster with a user with admin privileges.

Procedure

  1. Create the following NetworkPolicy objects:

    1. A policy named allow-from-openshift-ingress.

      $ cat << EOF| oc create -f -
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-from-openshift-ingress
spec:
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          policy-group.network.openshift.io/ingress: ""
  podSelector: {}
  policyTypes:
  - Ingress
EOF

      policy-group.network.openshift.io/ingress: "" is the preferred namespace selector label for OpenShift SDN. You can use the network.openshift.io/policy-group: ingress namespace selector label, but this is a legacy label.

    2. A policy named allow-from-openshift-monitoring:

      $ cat << EOF| oc create -f -
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-from-openshift-monitoring
spec:
  ingress:
  - from:
    - namespaceSelector:
        matchLabels:
          network.openshift.io/policy-group: monitoring
  podSelector: {}
  policyTypes:
  - Ingress
EOF

    3. A policy named allow-same-namespace:

      $ cat << EOF| oc create -f -
kind: NetworkPolicy
apiVersion: networking.k8s.io/v1
metadata:
  name: allow-same-namespace
spec:
  podSelector:
  ingress:
  - from:
    - podSelector: {}
EOF

  2. Optional: To confirm that the network policies exist in your current project, enter the following command:

    $ oc describe networkpolicy
    Example output
    Name:         allow-from-openshift-ingress
Namespace:    example1
Created on:   2020-06-09 00:28:17 -0400 EDT
Labels:       <none>
Annotations:  <none>
Spec:
  PodSelector:     <none> (Allowing the specific traffic to all pods in this namespace)
  Allowing ingress traffic:
    To Port: <any> (traffic allowed to all ports)
    From:
      NamespaceSelector: network.openshift.io/policy-group: ingress
  Not affecting egress traffic
  Policy Types: Ingress


Name:         allow-from-openshift-monitoring
Namespace:    example1
Created on:   2020-06-09 00:29:57 -0400 EDT
Labels:       <none>
Annotations:  <none>
Spec:
  PodSelector:     <none> (Allowing the specific traffic to all pods in this namespace)
  Allowing ingress traffic:
    To Port: <any> (traffic allowed to all ports)
    From:
      NamespaceSelector: network.openshift.io/policy-group: monitoring
  Not affecting egress traffic
  Policy Types: Ingress

Creating default network policies for a new project

As a cluster administrator, you can modify the new project template to automatically include NetworkPolicy objects when you create a new project.

Modifying the template for new projects

As a cluster administrator, you can modify the default project template so that new projects are created using your custom requirements.

To create your own custom project template:

Procedure

  1. Log in as a user with cluster-admin privileges.

  2. Generate the default project template:

    $ oc adm create-bootstrap-project-template -o yaml > template.yaml

  3. Use a text editor to modify the generated template.yaml file by adding objects or modifying existing objects.

  4. The project template must be created in the openshift-config namespace. Load your modified template:

    $ oc create -f template.yaml -n openshift-config

  5. Edit the project configuration resource using the web console or CLI.

    • Using the web console:

      1. Navigate to the Administration → Cluster Settings page.

      2. Click Configuration to view all configuration resources.

      3. Find the entry for Project and click Edit YAML.

    • Using the CLI:

      1. Edit the project.config.openshift.io/cluster resource:

        $ oc edit project.config.openshift.io/cluster

  6. Update the spec section to include the projectRequestTemplate and name parameters, and set the name of your uploaded project template. The default name is project-request.

    Project configuration resource with custom project template
    apiVersion: config.openshift.io/v1
kind: Project
metadata:
  ...
spec:
  projectRequestTemplate:
    name: <template_name>

  7. After you save your changes, create a new project to verify that your changes were successfully applied.

Adding network policies to the new project template

As a cluster administrator, you can add network policies to the default template for new projects. OKD will automatically create all the NetworkPolicy objects specified in the template in the project.

Prerequisites

  • Your cluster uses a default CNI network provider that supports NetworkPolicy objects, such as the OpenShift SDN network provider with mode: NetworkPolicy set. This mode is the default for OpenShift SDN.

  • You installed the OpenShift CLI (oc).

  • You must log in to the cluster with a user with cluster-admin privileges.

  • You must have created a custom default project template for new projects.

Procedure

  1. Edit the default template for a new project by running the following command:

    $ oc edit template <project_template> -n openshift-config

    Replace <project_template> with the name of the default template that you configured for your cluster. The default template name is project-request.

  2. In the template, add each NetworkPolicy object as an element to the objects parameter. The objects parameter accepts a collection of one or more objects.

    In the following example, the objects parameter collection includes several NetworkPolicy objects.

    objects:
- apiVersion: networking.k8s.io/v1
  kind: NetworkPolicy
  metadata:
    name: allow-from-same-namespace
  spec:
    podSelector: {}
    ingress:
    - from:
      - podSelector: {}
- apiVersion: networking.k8s.io/v1
  kind: NetworkPolicy
  metadata:
    name: allow-from-openshift-ingress
  spec:
    ingress:
    - from:
      - namespaceSelector:
          matchLabels:
            network.openshift.io/policy-group: ingress
    podSelector: {}
    policyTypes:
    - Ingress
...

  3. Optional: Create a new project to confirm that your network policy objects are created successfully by running the following commands:

    1. Create a new project:

      $ oc new-project <project> (1)
      1 Replace <project> with the name for the project you are creating.

    2. Confirm that the network policy objects in the new project template exist in the new project:

      $ oc get networkpolicy
NAME                           POD-SELECTOR   AGE
allow-from-openshift-ingress   <none>         7s
allow-from-same-namespace      <none>         7s

Optimizing routing

The OKD HAProxy router can be scaled or configured to optimize performance.

Baseline Ingress Controller (router) performance

The OKD Ingress Controller, or router, is the ingress point for ingress traffic for applications and services that are configured using routes and ingresses.

When evaluating a single HAProxy router performance in terms of HTTP requests handled per second, the performance varies depending on many factors. In particular:

  • HTTP keep-alive/close mode

  • route type

  • TLS session resumption client support

  • Number of concurrent connections per target route

  • Number of target routes

  • Back end server page size

  • Underlying infrastructure (network/SDN solution, CPU, and so on)

While performance in your specific environment will vary, Red Hat lab tests on a public cloud instance of size 4 vCPU/16GB RAM. A single HAProxy router handling 100 routes terminated by backends serving 1kB static pages is able to handle the following number of transactions per second.

In HTTP keep-alive mode scenarios:

Encryption LoadBalancerService HostNetwork

none

21515

29622

edge

16743

22913

passthrough

36786

53295

re-encrypt

21583

25198

In HTTP close (no keep-alive) scenarios:

Encryption LoadBalancerService HostNetwork

none

5719

8273

edge

2729

4069

passthrough

4121

5344

re-encrypt

2320

2941

The default Ingress Controller configuration was used with the spec.tuningOptions.threadCount field set to 4. Two different endpoint publishing strategies were tested: Load Balancer Service and Host Network. TLS session resumption was used for encrypted routes. With HTTP keep-alive, a single HAProxy router is capable of saturating a 1 Gbit NIC at page sizes as small as 8 kB.

When running on bare metal with modern processors, you can expect roughly twice the performance of the public cloud instance above. This overhead is introduced by the virtualization layer in place on public clouds and holds mostly true for private cloud-based virtualization as well. The following table is a guide to how many applications to use behind the router:

Number of applications Application type

5-10

static file/web server or caching proxy

100-1000

applications generating dynamic content

In general, HAProxy can support routes for up to 1000 applications, depending on the technology in use. Ingress Controller performance might be limited by the capabilities and performance of the applications behind it, such as language or static versus dynamic content.

Ingress, or router, sharding should be used to serve more routes towards applications and help horizontally scale the routing tier.

Post-installation OpenStack network configuration

You can configure some aspects of an OKD on OpenStack cluster after installation.

Configuring application access with floating IP addresses

After you install OKD, configure OpenStack to allow application network traffic.

You do not need to perform this procedure if you provided values for platform.openstack.apiFloatingIP and platform.openstack.ingressFloatingIP in the install-config.yaml file, or os_api_fip and os_ingress_fip in the inventory.yaml playbook, during installation. The floating IP addresses are already set.
Prerequisites

  • OKD cluster must be installed

  • Floating IP addresses are enabled as described in the OKD on OpenStack installation documentation.

Procedure

After you install the OKD cluster, attach a floating IP address to the ingress port:

  1. Show the port:

    $ openstack port show <cluster_name>-<cluster_ID>-ingress-port

  2. Attach the port to the IP address:

    $ openstack floating ip set --port <ingress_port_ID> <apps_FIP>

  3. Add a wildcard A record for *apps. to your DNS file:

    *.apps.<cluster_name>.<base_domain>  IN  A  <apps_FIP>

If you do not control the DNS server but want to enable application access for non-production purposes, you can add these hostnames to /etc/hosts:

<apps_FIP> console-openshift-console.apps.<cluster name>.<base domain>
<apps_FIP> integrated-oauth-server-openshift-authentication.apps.<cluster name>.<base domain>
<apps_FIP> oauth-openshift.apps.<cluster name>.<base domain>
<apps_FIP> prometheus-k8s-openshift-monitoring.apps.<cluster name>.<base domain>
<apps_FIP> grafana-openshift-monitoring.apps.<cluster name>.<base domain>
<apps_FIP> <app name>.apps.<cluster name>.<base domain>

Kuryr ports pools

A Kuryr ports pool maintains a number of ports on standby for pod creation.

Keeping ports on standby minimizes pod creation time. Without ports pools, Kuryr must explicitly request port creation or deletion whenever a pod is created or deleted.

The Neutron ports that Kuryr uses are created in subnets that are tied to namespaces. These pod ports are also added as subports to the primary port of OKD cluster nodes.

Because Kuryr keeps each namespace in a separate subnet, a separate ports pool is maintained for each namespace-worker pair.

Prior to installing a cluster, you can set the following parameters in the cluster-network-03-config.yml manifest file to configure ports pool behavior:

  • The enablePortPoolsPrepopulation parameter controls pool prepopulation, which forces Kuryr to add ports to the pool when it is created, such as when a new host is added, or a new namespace is created. The default value is false.

  • The poolMinPorts parameter is the minimum number of free ports that are kept in the pool. The default value is 1.

  • The poolMaxPorts parameter is the maximum number of free ports that are kept in the pool. A value of 0 disables that upper bound. This is the default setting.

    If your OpenStack port quota is low, or you have a limited number of IP addresses on the pod network, consider setting this option to ensure that unneeded ports are deleted.

  • The poolBatchPorts parameter defines the maximum number of Neutron ports that can be created at once. The default value is 3.

Adjusting Kuryr ports pool settings in active deployments on OpenStack

You can use a custom resource (CR) to configure how Kuryr manages OpenStack Neutron ports to control the speed and efficiency of pod creation on a deployed cluster.

Procedure

  1. From a command line, open the Cluster Network Operator (CNO) CR for editing:

    $ oc edit networks.operator.openshift.io cluster

  2. Edit the settings to meet your requirements. The following file is provided as an example:

    apiVersion: operator.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  clusterNetwork:
  - cidr: 10.128.0.0/14
    hostPrefix: 23
  serviceNetwork:
  - 172.30.0.0/16
  defaultNetwork:
    type: Kuryr
    kuryrConfig:
      enablePortPoolsPrepopulation: false (1)
      poolMinPorts: 1 (2)
      poolBatchPorts: 3 (3)
      poolMaxPorts: 5 (4)
    1 Set enablePortPoolsPrepopulation to true to make Kuryr create new Neutron ports after a namespace is created or a new node is added to the cluster. This setting raises the Neutron ports quota but can reduce the time that is required to spawn pods. The default value is false.
    2 Kuryr creates new ports for a pool if the number of free ports in that pool is lower than the value of poolMinPorts. The default value is 1.
    3 poolBatchPorts controls the number of new ports that are created if the number of free ports is lower than the value of poolMinPorts. The default value is 3.
    4 If the number of free ports in a pool is higher than the value of poolMaxPorts, Kuryr deletes them until the number matches that value. Setting the value to 0 disables this upper bound, preventing pools from shrinking. The default value is 0.

  3. Save your changes and quit the text editor to commit your changes.

Modifying these options on a running cluster forces the kuryr-controller and kuryr-cni pods to restart. As a result, the creation of new pods and services will be delayed.