Open Shift Redhat pod IP Exhaustion on Pod Subnet

Products

• VMware Container Networking with Antrea

Issue/Introduction

An OpenShift Pod subnet experiences IP address exhaustion, resulting in a failure to assign IP addresses to newly provisioned pods.

The Antrea agent logs (antrea-agent-ubi) display the following error indicating IP exhaustion: Failed to request IP addresses for container...

failed to allocate for range 0: no IP addresses available in range set:

Environment

• Open Shift red hat 
• VMWare Container networking with Antrea  

Cause

The configured IP pool for the OpenShift cluster is undersized for the requested pod scale, causing IP address depletion within the defined subnet range for the Antrea CNI.

Resolution

Note: As this involves third-party configuration (Red Hat OpenShift/Antrea CNI), VMware by Broadcom Support does not actively troubleshoot or alter this environment. Please consult Red Hat documentation for exact syntax on expanding IP pools, For further assistance with Antrea CNI and OpenShift IP pool sizing, engage Red Hat Support.

1. Verify the current IP pool allocation within the OpenShift cluster and identify the exhausted subnet.

2. Expand the IP pool configuration within the Red Hat OpenShift environment to accommodate the required pod scale.

3. Alternatively, redeploy the affected pods utilizing a newly defined, larger subnet range.