kubectl-evict-pod

kubectl-evict-pod

This plugin evicts the given pod. useful for testing pod disruption budget rules

Usage

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          9m55s
etcd-minikube                      1/1     Running   3          27d
kube-addon-manager-minikube        1/1     Running   13         27d
kube-apiserver-minikube            1/1     Running   3          27d
kube-controller-manager-minikube   1/1     Running   0          9h
kube-proxy-cwwm8                   1/1     Running   3          27d
kube-scheduler-minikube            1/1     Running   5          27d
storage-provisioner                1/1     Running   6          27d

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

# observe that 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
etcd-minikube                      1/1     Running   3          27d
kube-addon-manager-minikube        1/1     Running   13         27d
kube-apiserver-minikube            1/1     Running   3          27d
kube-controller-manager-minikube   1/1     Running   0          9h
kube-proxy-cwwm8                   1/1     Running   3          27d
kube-scheduler-minikube            1/1     Running   5          27d
storage-provisioner                1/1     Running   6          27d

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          4m6s
coredns-fb8b8dccf-826fh            1/1     Running   0          14m
etcd-minikube                      1/1     Running   3          27d
kube-addon-manager-minikube        1/1     Running   13         27d
kube-apiserver-minikube            1/1     Running   3          27d
kube-controller-manager-minikube   1/1     Running   0          9h
kube-proxy-cwwm8                   1/1     Running   3          27d
kube-scheduler-minikube            1/1     Running   5          27d
storage-provisioner                1/1     Running   6          27d

# 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          21m
etcd-minikube                      1/1     Running   3          27d
kube-addon-manager-minikube        1/1     Running   13         27d
kube-apiserver-minikube            1/1     Running   3          27d
kube-controller-manager-minikube   1/1     Running   0          9h
kube-proxy-cwwm8                   1/1     Running   3          27d
kube-scheduler-minikube            1/1     Running   5          27d
storage-provisioner                1/1     Running   6          27d