Control Groups

The cgroups is used to gather Control Group configuration from a linux based system and stores this information on a json file. The collector expects an optional mountPoint parameter where the cgroup virtual filesystem is expected to be mounted. The collector checks for the version of cgroups and all enabled controllers.

Parameters

In addition to the shared collector properties, the cgroups collector accepts the following parameters:

mountPoint (Optional)

Mount point path of the cgroup virtual filesystem. If it's not provided, the collector will default to /sys/fs/cgroup. This the default mount point used in most systems and and the default for systemd.

Example Collector Definition

apiVersion: troubleshoot.sh/v1beta2
kind: HostPreflight
metadata:
  name: sample
spec:
  collectors:
    - cgroups:
        collectorName: cgroups
        mountPoint: /sys/fs/cgroup

Included resources

/host-collectors/system/cgroups.json

This will contain the JSON results of the collected cgroups configuration. There will be a "cgroup-enabled" boolean field that will be true whenever the collector detects either cgroup v1 or cgroup v2 in the mounted filesystem. There is also "allControllers" array which will contain all detected controllers. This field is meant to make it easier for analyzers to test if a controller is enabled or not regardless of the cgroup version.

Example of the resulting JSON files

Version 1

{
  "cgroup-enabled": true,
  "cgroup-v1": {
    "enabled": false,
    "mountPoint": "",
    "controllers": []
  },
  "cgroup-v2": {
    "enabled": true,
    "mountPoint": "/sys/fs/cgroup",
    "controllers": [
      "cpuset",
      "cpu",
      "io",
      "memory",
      "hugetlb",
      "pids",
      "rdma",
      "misc",
      "freezer",
      "devices"
    ]
  },
  "allControllers": [
    "cpu",
    "cpuset",
    "devices",
    "freezer",
    "hugetlb",
    "io",
    "memory",
    "misc",
    "pids",
    "rdma"
  ]
}

Version 2

{
  "cgroup-enabled": true,
  "cgroup-v1": {
    "enabled": false,
    "mounts": null,
    "controllers": null
  },
  "cgroup-v2": {
    "enabled": true,
    "mountPoint": "/sys/fs/cgroup",
    "controllers": [
      "cpuset",
      "cpu",
      "io",
      "memory",
      "hugetlb",
      "pids",
      "rdma",
      "misc",
      "freezer",
      "devices"
    ]
  }
}