understanding kubernetes codebase

• Jun 14th, 2023
  • going through issue/117070 and pull/117793
  • the above issue and pr are to use memory.oom.group from cgroup v2 to kill all the processes running in a group. Before this only the parent process is terminated and all the children are left behind.
  • memory.oom.group allows to kill the entire group incase of oom.
  • there is only a small change in the code base in pkg/kubelet/kuberuntime in the calculateLinuxResources function.
  • https://github.dev/kubernetes/kubernetes/pull/117793

  • //If request is not specified, but limit is, we want request to default to limit

  • the above functionality is implemented here.

  • // runc requires cgroupv2 for unified mode
    	if libcontainercgroups.IsCgroup2UnifiedMode() {
    		resources.Unified = map[string]string{
    			// Ask the kernel to kill all processes in the container cgroup in case of OOM.
    			// See memory.oom.group in https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html for
    			// more info.
    			"memory.oom.group": "1",
    		}
    	}