Beware of true in Pod specifications

true is a reserved word in YAML and this can bite you when you least expect it. Consider the following extremely simple Pod and livenessProbe:

apiVersion: v1
kind: Pod
metadata:
  name: true-test
spec:
  containers:
  - name: nginx
    image: nginx
    livenessProbe:
      exec:
        command:
        - true

Let’s create this, shall we?

$ kubectl create -f true.yaml 

Error from server (BadRequest): error when creating "true.yaml": Pod in version "v1" cannot be handled as a Pod: v1.Pod.Spec: v1.PodSpec.Containers: []v1.Container: v1.Container.LivenessProbe: v1.Probe.Handler: Exec: v1.ExecAction.Command: []string: ReadString: expects " or n, but found t, error found in #10 byte of ...|ommand":[true]}},"na|..., bigger context ...|age":"nginx","livenessProbe":{"exec":{"command":[true]}},"name":"nginx"}]}}
|...
$

All because in the above specification, true is not quoted, as it should:

    livenessProbe:
      exec:
        command:
        - "true"

A different take, if you do not want to mess with true would be:

   livenessProbe:
      exec:
        command:
        - exit

Beware though, if you want to exit 0 you need to quote again:

   livenessProbe:
      exec:
        command:
        - exit
        - "0"

Oh, the many ways you can waste your time…

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