Configuring the node port <strong>service</strong> range | Networking

Expanding the node port range
Additional resources

During cluster installation, you can configure the node port range to meet the requirements of your cluster. After cluster installation, only a cluster administrator can expand the range as a postinstallation task. If your cluster uses a large number of node ports, consider increasing the available port range according to the requirements of your cluster.

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

If you do not set a node port range during cluster installation, the default range of 30000-32768 applies to your cluster. In this situation, you can expand the range on either side, but you must preserve 30000-32768 within your new port range.

If you expand the node port range and OpenShift CLI (oc) stops working because of a port conflict with the OpenShift API server, you must create a new cluster. Ensure that the new node port range does not overlap with any ports already in use by host processes or pods that are configured with host networking.

Expanding the node port range

You can expand the node port range for your cluster. However, after you install your OKD cluster, you cannot contract the node port range on either side.

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

Expand the range for the serviceNodePortRange parameter in the network.config.openshift.io object that your cluster uses to manage traffic for pods by entering the following command in your command-line interface (CLI):

$ oc patch network.config.openshift.io cluster --type=merge -p \
  '{
    "spec":
      { "serviceNodePortRange": "<port_range>" } (1)
  }'

1	Where `<port_range>` is your 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 a successful configuration, 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"]

Configuring the node port service range

Expanding the node port range

Additional resources