Change Details

We're currently running k8s nodes with cgroup v2 disabled (systemd.unified_cgroup_hierarchy=0) as kubelet 1.16 only supports v1. We're also running docker with `cgroupfs` which is said to cause instability under pressure. With the k8s 1.23 update we should: * Enable cgroup v2: `systemd.unified_cgroup_hierarchy=1` * Docker supports cgroup v2 since Docker 20.10. Running Docker on cgroup v2 also requires the following conditions to be satisfied: ** containerd: v1.4 or later ** runc: v1.0.0-rc91 or later ** Kernel: v4.15 or later (v5.2 or later is recommended) * Switch the docker cgroup driver to systemd: `native.cgroupdriver=systemd` (https://gerrit.wikimedia.org/r/c/operations/puppet/+/524186) * Ensure kubelet runs with cgroup driver systemd as well: `--cgroup-driver=systemd` https://v1-23.docs.kubernetes.io/docs/setup/production-environment/container-runtimes/#cgroup-drivers https://v1-23.docs.kubernetes.io/docs/tasks/administer-cluster/reserve-compute-resources/#configuring-a-cgroup-driver See also: {T277876}