Need a working Kubectl binary inside an image - docker

Question

My goal is to have a pod with a working Kubectl binary inside.
Unfortunatly every kubectl image from docker hub I booted using basic yaml resulted in CrashLoopbackOff or else.
Has anyone got some yaml (deployment, pod, etc) that would get me my kubectl ?
I tried a bunch of images with this basic yaml there:
apiVersion: apps/v1
kind: Deployment
metadata:
name: kubectl-demo
labels:
app: deploy
role: backend
spec:
replicas: 1
selector:
matchLabels:
app: deploy
role: backend
template:
metadata:
labels:
app: deploy
role: backend
spec:
containers:
- name: kubectl-demo
image: <SOME_IMAGE>
ports:
- containerPort: 80
Thx

Answer 1

Or, you can do this. It works in my context, with kubernetes on VMs, where I know where is kubeconfig file. You would need to make the necessary changes, to make it work in your environment.
apiVersion: apps/v1
kind: Deployment
metadata:
name: kubectl
spec:
replicas: 1
selector:
matchLabels:
role: kubectl
template:
metadata:
labels:
role: kubectl
spec:
containers:
- image: viejo/kubectl
name: kubelet
tty: true
securityContext:
privileged: true
volumeMounts:
- name: kube-config
mountPath: /root/.kube/
volumes:
- name: kube-config
hostPath:
path: /home/$USER/.kube/
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: node-role.kubernetes.io/master
operator: Exists
tolerations:
- effect: NoSchedule
key: node-role.kubernetes.io/master
operator: Exists
This is the result:
$ kubectl get po
NAME READY STATUS RESTARTS AGE
kubectl-cb8bfc6dd-nv6ht 1/1 Running 0 70s
$ kubectl exec kubectl-cb8bfc6dd-nv6ht -- kubectl get no
NAME STATUS ROLES AGE VERSION
kubernetes-1-17-master Ready master 16h v1.17.3
kubernetes-1-17-worker Ready <none> 16h v1.17.3

Answer 2

As Suren already explained in the comments that kubectl is not a daemon so kubectl will run, exit and cause the container to restart.
There are a couple of workarounds for this. One of these is to use sleep command with infinity argument. This would keep the Pod alive, prevent it from restarting and allow you to exec into it.
Here`s an example how to do that:
spec:
containers:
- image: bitnami/kubectl
command:
- sleep
- "infinity"
name: kctl
Let me know if this helps.