Pass file to docker container in a kubernetes Pod - docker

Question

I'm beginner in Kubernetes, what I would like to achieve is :
Pass user's ssh private/public key to the Pod and then to the Docker container (there's a shell script that will be using this key)
So I would like to know if it's possible to do that in the Kubectl apply ?
My pod.yaml looks like :
apiVersion: v1
kind: Pod
metadata:
generateName: testing
labels:
type: testing
namespace: ns-test
name: testing-config
spec:
restartPolicy: OnFailure
hostNetwork: true
containers:
- name: mycontainer
image: ".../mycontainer:latest"

Answer 1

you have to store the private / public key in a kubernetes secret object
apiVersion: v1
kind: Secret
metadata:
name: mysshkey
namespace: ns-test
data:
id_rsa: {{ value }}
id_rsa.pub: {{ value }}
and now you can mount this secret file in your container:
containers:
- image: "my-image:latest"
name: my-app
...
volumeMounts:
- mountPath: "/var/my-app"
name: ssh-key
readOnly: true
volumes:
- name: ssh-key
secret:
secretName: mysshkey
The documentation of kuberentes provides also an chapter of Using Secrets as files from a Pod
It's not tested but i hope it works.

Answer 2

First, you create a secret with your keys: kubectl create secret generic mysecret-keys --from-file=privatekey=</path/to/the/key/file/on/your/host> --from-file=publickey=</path/to/the/key/file/on/your/host>
Then you refer to the key files using the secret in your pod:
apiVersion: v1
kind: Pod
metadata:
...
spec:
...
containers:
- name: mycontainer
image: ".../mycontainer:latest"
volumeMounts:
- name: mysecret-keys
mountPath: /path/in/the/container # <-- privatekey & publickey will be mounted as file in this directory where your shell script can access
volumes:
- name: mysecret-keys
secret:
secretName: mysecret-keys # <-- mount the secret resource you created above
You can check the secret with kubectl get secret mysecret-keys --output yaml. You can check the pod and its mounting with kubectl describe pod testing-config.