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Configuring the node port service range

To meet your cluster node port requirements in OKD, you can configure the node port service range during installation or expand it after installation. You can expand the default range of 30000-32768 on either side while preserving this default range within your new configuration.

Red Hat has not performed testing outside the default port range of 30000-32768. For ranges outside the default port range, ensure that you test to verify the expanding node port range does not impact your cluster. In particular, ensure that there is:

  • No overlap with any ports already in use by host processes

  • No overlap with any ports already in use by pods that are configured with host networking

If you expanded the range and a port allocation issue occurs, create a new cluster and set the required range for it.

If you expand the node port range and OpenShift CLI (oc) stops working because of a port conflict with the OKD API server, you must create a new cluster.

Expanding the node port range

To expand the node port range for your OKD cluster after installation, you can use the oc patch command to update the serviceNodePortRange parameter. You can expand the range on either side, but you cannot shrink it after installation.

Red Hat has not performed testing outside the default port range of 30000-32768. For ranges outside the default port range, ensure that you test to verify that expanding your node port range does not impact your cluster. If you expanded the range and a port allocation issue occurs, create a new cluster and set the required range for it.
Prerequisites

  • Installed the OpenShift CLI (oc).

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

  • You ensured that your cluster infrastructure allows access to the ports that exist in the extended range. For example, if you expand the node port range to 30000-32900, your firewall or packet filtering configuration must allow the inclusive port range of 30000-32900.

Procedure

  • To expand the range for the serviceNodePortRange parameter in the network.config.openshift.io object that your cluster uses to manage traffic for pods, enter the following command:

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

    where:

    <port_range>

    Specifies the expanded range, such as 30000-32900.

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

    apiVersion: config.openshift.io/v1
kind: Network
metadata:
  name: cluster
spec:
  serviceNodePortRange: "<port_range>"
# ...
    Example output
    network.config.openshift.io/cluster patched
Verification

  • To confirm that the updated configuration is active, enter the following command. The update can take several minutes 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":["30000-32900"]

Additional resources