Kubernetes while redirection into a file

November 20, 2023 - 1 minutes read - 168 words

My first attemp to resolve "Kubernetes Time Check Pod" in https://engineer.kodekloud.com is not successful. The exercise doesn’t allow to open an editor to edit a yaml file. I had to resort to cat. I attempted several times to resolve it on my local cluster, still no luck even I tried different combination such as command, args,string in string, avoiding expansion. This one from stackoverfow gave me a clue how to resolve my issue.

The lessons I learnt from this one:

My final solution is below:

cat <<'EOF' | kubectl apply -f -
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: time-check
  name: time-check
  namespace: datacenter
spec:
  volumes:
  - name: log-volume
    emptyDir: {}
  containers:
  - image: busybox:latest
    name: time-check
    env:
    - name: TIME_FREQ
      valueFrom:
        configMapKeyRef:
          name: time-config
          key: TIME_FREQ
    command: ["/bin/sh"]
    args: ["-c", "while true; do date; sleep $(TIME_FREQ); done > /opt/data/time/time-check.log"]
    resources: {}
    volumeMounts:
    - name: log-volume
      mountPath: /opt/data/time
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}
EOF