Is there a way to wait for all pod from a k8s deployment to be stopped?-CodePudding

When deleting a pod manually kubectl delete wait for the pod to be deleted and one can include a kubectl wait --for.... condition in a script to wait for the pod to be deleted.

I would like to perform the same wait condition but when scaling down (replicas: 0) a deployment.

From the deployment json, the available/unavailable replicas doesn't count the "terminating" pods and as expected kubectl wait --for=delete deployment test-dep doesn't wait for pod termination but for deployment deletion.

So I would like to perform on my script:

kubectl scale --replicas=0 deployment foo-bar
kubectl wait --for=deletion-of-pod-from-deploymenent=foo-bar

Is there a way to do that?

Remarks: I would like to have the code as generic as possible so no hard writing the labels from deployment.

CodePudding user response：

The easiest way would be to use labels and issue kubectl wait based on that.

kubectl wait --for delete pod --selector=<label>=<value>

but, since you don't want that, you can use the script below

#!/bin/bash

deployment_uid=$(kubectl get deployments ${1} -o=jsonpath='{.metadata.uid}')
rs_uids=$(kubectl get rs -o=json | jq -r '.items[] | select(.metadata.ownerReferences[].uid=='\"${deployment_uid}\"') | .metadata.uid')

PODS=""

for i in $rs_uids; do
    PODS =$(kubectl get pods -o=json | jq -r '.items[] | select(.metadata.ownerReferences[].uid=='\"$i\"') | "pod/"   .metadata.name')
done

[ -z "$PODS" ] && echo "Pods not found" || kubectl wait --for=delete --timeout=-1s ${PODS}

This uses Deployment name (as a first argument), to get ownerRefereces UIDs, chaining down to Pods names.

It's much more complicated, and prone to failure, than just using labels.