Add option to mount host path for cgroups

Capability added to disable cgroups host path volume

Change-Id: I007d9a79b812094126fadb36fd743133495d337f

charts/maas/templates/statefulset-rack.yaml

@@ -94,9 +94,11 @@ spec:
             - /tmp/start.sh
 {{ dict "envAll" $envAll "component" "rack" "container" "maas-rack" "type" "readiness" "probeTemplate" (include "maasrackreadinessProbeTemplate" $envAll | fromYaml) | include "helm-toolkit.snippets.kubernetes_probe" | indent 10 }}
           volumeMounts:
+{{- if not .Values.conf.maas.cgroups.disable_cgroups_rack }}
             - mountPath: /sys/fs/cgroup
               name: host-sys-fs-cgroup
               readOnly: true
+{{- end }}
             - mountPath: /run
               name: pod-run
             - mountPath: /run/lock
@@ -155,9 +157,11 @@ spec:
               readOnly: true
 {{ if $mounts_maas_rack.volumeMounts }}{{ toYaml $mounts_maas_rack.volumeMounts | indent 12 }}{{ end }}
       volumes:
+{{- if not .Values.conf.maas.cgroups.disable_cgroups_rack }}
         - name: host-sys-fs-cgroup
           hostPath:
             path: /sys/fs/cgroup
+{{- end }}
         - name: host-cloud-init
           hostPath:
             path: /run/cloud-init

charts/maas/templates/statefulset-region.yaml

@@ -108,9 +108,11 @@ spec:
           command:
             - /tmp/start.sh
           volumeMounts:
+{{- if not .Values.conf.maas.cgroups.disable_cgroups_region }}
             - mountPath: /sys/fs/cgroup
               name: host-sys-fs-cgroup
               readOnly: true
+{{- end }}
             - mountPath: /run
               name: pod-run
             - mountPath: /run/lock
@@ -179,9 +181,11 @@ spec:
               readOnly: true
 {{- if $mounts_maas_region.volumeMounts }}{{ toYaml $mounts_maas_region.volumeMounts | indent 12 }}{{ end }}
       volumes:
+{{- if not .Values.conf.maas.cgroups.disable_cgroups_region }}
         - name: host-sys-fs-cgroup
           hostPath:
             path: /sys/fs/cgroup
+{{- end }}
         - name: pod-run
           emptyDir: {}
         - name: pod-run-lock

charts/maas/values.yaml

@@ -234,6 +234,11 @@ conf:
     url:
       maas_url: null
     ingress_disable_gui: false
+    cgroups:
+      # When set to true, this won't mount the host path /sys/fs/cgroup. Used
+      # to enable use of cgroups v2. Also requires running container as privileged
+      disable_cgroups_region: false
+      disable_cgroups_rack: false
     ntp:
       # These options allow you to mock out the ntpd binary within the container
       # by overwriting it with a script that simply sleeps - this is useful in