Chapter 5. Known issues

Using container CPU resource limits to increase the number of available CPUs for a pod fails if the requested CPUs are offline. If the functionality is available, you can diagnose CPU resource issues by running the oc rsh <pod> command to access a pod and then running the lscpu command:

$ lscpu

Example output:

CPU(s):                                16
On-line CPU(s) list:             0-12,14,15
Off-line CPU(s) list:            13

The list of offline CPUs is unpredictable and can change from run to run.

To work around this problem, use a pod annotation to request additional CPUs as in the following example:

metadata:
  annotations:
    io.katacontainers.config.hypervisor.default_vcpus: "16"

Jira:KATA-1376

You cannot use the sizeLimit parameter in the pod specification to expand ephemeral volumes because the volume size default is 50% of the memory assigned to the sandboxed container.

To work around this problem, change the size by remounting the volume. For example, if the memory assigned to the sandboxed container is 6 GB and the ephemeral volume is mounted at /var/lib/containers, you can increase the size of this volume beyond the 3 GB default by running the following command:

$ mount -o remount,size=4G /var/lib/containers

Note that the mount command needs to run inside the pod. You can either have this as part of the pod manifest itself or you can start a shell session in the pod by running oc rsh and execute the mount command.

Jira:KATA-2579