Mount sentinel-location without sentinel-command

[ckotzbauer]

Wait with merge until kubereboot/kured#813 is released.

[rptaylor]

This works in my testing in conjunction with kubereboot/kured#813
My values:

image:
  repository: ghcr.io/ckotzbauer/kured
  tag: 1.14.0-alpha.0
configuration:
  period: "0h0m30s"
  rebootDelay: 0h1m0s
  rebootSentinel: /var/lib/example/reboot-required
extraArgs:
  reboot-method: signal
containerSecurityContext:
  readOnlyRootFilesystem: true
  privileged: false
  allowPrivilegeEscalation: false
  capabilities:
    drop: ["*"]
    add: ["CAP_KILL"]

Then I confirmed that the kured pods were deployed with:

  containers:
  - args:
    - --ds-name=kured
    - --ds-namespace=kured
    - --metrics-port=8080
    - --period=0h0m30s
    - --reboot-sentinel=/sentinel/reboot-required
    - --reboot-command=/bin/systemctl reboot
    - --reboot-delay=0h1m0s
    - --log-format=text
    - --reboot-method=signal

  volumeMounts:
    - mountPath: /sentinel
      name: sentinel
      readOnly: true

  - hostPath:
      path: /var/lib/example
      type: ""
    name: sentinel

Then on a node I touch /var/lib/example/reboot-required and the node reboooted.

[ckotzbauer]

Thanks @rptaylor for review and testing, I adjusted the PR.