kubectl-evict-pod

kubectl-evict-pod

This plugin evicts pods:

• for testing pod disruption budget rules
• safely restarting applications

Usage

• evict single pod: kubectl evict-pod <pod-name> -n <namespace>
• evict multiple pods: kubectl evict-pod -n <namespace> -l app=foo
• evict multiple pods until every one is gone: kubectl evict-pod -n <namespace> -l app=foo --retry
• show options: kubectl evict-pod -h

Install

kubectl krew install evict-pod

Testing

Pod evicted successfully scenario

# before running the evict-pod command
$ kubectl get pods -n kube-system
NAME                               READY   STATUS    RESTARTS   AGE
coredns-fb8b8dccf-6wvj6            1/1     Running   0          10m
coredns-fb8b8dccf-826fh            1/1     Running   0          11m

# now lets evict 1 coredns pod
$ ./kubectl-evict-pod coredns-fb8b8dccf-6wvj6 -n kube-system
INFO[0000] pod "coredns-fb8b8dccf-6wvj6" in namespace kube-system evicted successfully 

# the pod has been evicted successfully
$ kubectl get pods -n kube-system
NAME                               READY   STATUS    RESTARTS   AGE
coredns-fb8b8dccf-7ngmk            1/1     Running   0          42s
coredns-fb8b8dccf-826fh            1/1     Running   0          11m

Pod eviction prevented by pod disruption budget

• create the pod disruption budget using following spec

apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: coredns-pdb
spec:
  minAvailable: 2
  selector:
    matchLabels:
      k8s-app: kube-dns

• apply the pod disruption budget to the cluster

# lets apply the pod disruption budget
$ kubectl apply -f pdb.yaml -n kube-system
poddisruptionbudget.policy/coredns-pdb created

• Now lets try to evict the pods again

# get existing pods
$ kubectl get pods -n kube-system
NAME                               READY   STATUS    RESTARTS   AGE
coredns-fb8b8dccf-7ngmk            1/1     Running   0          10m
coredns-fb8b8dccf-826fh            1/1     Running   0          11m

# now lets try to evict the pod again
$ ./kubectl-evict-pod coredns-fb8b8dccf-826fh -n kube-system
Error: Cannot evict pod as it would violate the pod\'s disruption budget.
exit status 1

# observe pods continue to run
$ kubectl get pods -n kube-system
NAME                               READY   STATUS    RESTARTS   AGE
coredns-fb8b8dccf-7ngmk            1/1     Running   0          10m
coredns-fb8b8dccf-826fh            1/1     Running   0          11m

Development

Update the code and use go run . <args> to test.