field is immutable k8s

I got the message the job spec is invalid ... the field is immutable for a different reason and wanted to briefly share it here.

I was trying to apply this yaml file:

apiVersion: extensions/v1beta1kind: Deploymentspec:  selector:    matchLabels:      app: application-name...

Turns out that this yaml was going to replace a previous version of the same Deployment. When I ran kubectl get deployment application-name -o yaml I saw this:

apiVersion: extensions/v1beta1kind: Deploymentspec:  selector:    matchLabels:      app: application-name      track: stable...

Apparently the spec.selector.matchLabels is currently an array, and I was trying to replace that with a single string. My fix was deleting the deployment and re-deploying it.

If you are using args in a Pod definition it's meant to be an array with single-string items. (It doesn't run the command in a shell) For example:

args:        - /cloud_sql_proxy        - -instances        - ...

or

args:  [ "/cloud_sql_proxy", "-instances", "..." ]

The way to get around this is to run the command in a shell:

command: [ "/bin/sh" ]args:         - -c        - |          /cloud_sql_proxy -instances=xxxxxxxxxxx:europe-west1:xxxxxxxxxxx=tcp:5432 -credential_file=/secrets/cloudsql/credentials.json -log_debug_stdout=true &          CHILD_PID=$!          (while true; do echo "waiting for termination file"; if [[ -f "/tmp/pod/main-terminated" ]]; then kill ; echo "Killed  as the main container terminated."; fi; sleep 1; done) &          wait           if [[ -f "/tmp/pod/main-terminated" ]]; then exit 0; echo "Job completed. Exiting..."; fi

The quotes(") on the array are for readability, they can be no quotes or single quotes(') too (As seen in the YAML specs)

Hope it helps.

So this issue was resolved. I had to wrap the values of the environment variables in the yaml file in quotes. That resolved the issue.

- name: DATABASE_URL:  value: "${DATABASE_URL}"