Exercise

1. Create a Pod with a single container based on mongo:5.0 and ensure it persists its data in an ephemeral volume

Hint: Mongo persists the data in it’s /data/db folder

2. Run a shell in the container and list the content of the /data/db folder

3. Get the unique identifier of the Pod

Hint: this can be retrieved in the property .metadata.uid

4. On which node is this Pod running

5. Run a shell on the node this Pod is running on and retrieve the content of the volume

Hint: it’s located in /var/lib/kubelet/pods/POD_ID/volumes/kubernetes.io~empty-dir/data

6. Delete the Pod

Documentation

https://kubernetes.io/docs/concepts/storage/volumes/#emptydir

kubectl run mongo --image=mongo:5.0 --dry-run=client -o yaml > pod.yaml

apiVersion: v1
kind: Pod
metadata:
  labels:
    run: mongo
  name: mongo
spec:
  containers:
  - image: mongo:5.0
    name: mongo
    volumeMounts:
    - name: data
      mountPath: /data/db
  volumes:
  - name: data
    emptyDir: {}

k apply -f pod.yaml

k exec mongo -- ls /data/db

k get po mongo -o jsonpath={.metadata.uid}

k get po mongo -o wide

sudo ls /var/lib/kubelet/pods/POD_ID/volumes/kubernetes.io~empty-dir/data

k delete po mongo