Configuring the Linux cgroup version on your nodes

    cgroup v2 is the next version of the kernel control group and offers multiple improvements. However, it can have some unwanted effects on your nodes.

    You can switch to Linux control group version 1 (cgroup v1), if needed, by using a machine config. Enabling cgroup v1 in OKD disables the cgroup v2 controllers and hierarchies in your cluster.

    Prerequisites

    • Have administrative privilege to a working OKD cluster.

    Procedure

    2. Create the new machine config:

      1. $ oc create -f 05-worker-cgroup-v1.yaml

    3. Check to see that the new machine config was added:

        Example output

      1. Check the nodes:

        1. $ oc get nodes
        1. NAME                           STATUS                     ROLES    AGE   VERSION
        3. ip-10-0-136-243.ec2.internal   Ready                      master   34m   v1.26.0
        4. ip-10-0-141-105.ec2.internal   Ready,SchedulingDisabled   worker   28m   v1.26.0
        5. ip-10-0-153-11.ec2.internal    Ready                      worker   28m   v1.26.0
        6. ip-10-0-153-150.ec2.internal   Ready                      master   34m   v1.26.0

        You can see that the command disables scheduling on each worker node.

      2. After a node returns to the state, start a debug session for that node:

      3. Set /host as the root directory within the debug shell:

        1. sh-4.4# chroot /host

      4. Check that the sys/fs/cgroup/cgroup2fs file has been moved to the tmpfs file system: