A. kubectl run nginx --image=nginx --restart=Never --env=var1=val1
# then
kubectl exec -it nginx -- env
# or
kubectl run nginx --restart=Never --image=nginx --env=var1=val1
-it --rm -- env

B. kubectl run nginx --image=nginx --restart=Never --env=var1=val1
# then
kubectl exec -it nginx -- env
# or
kubectl exec -it nginx -- sh -c 'echo $var1'
# or
kubectl describe po nginx | grep val1
# or
kubectl run nginx --restart=Never --image=nginx --env=var1=val1
-it --rm - env

A. vim task-pv-volume.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: task-pv-volume
labels:
type: local
spec:
storageClassName: ""
capacity:
storage: 5Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data"
kubectl apply -f task-pv-volume.yaml
//Verify
kubectl get pv
NAME CAPACITY ACCESS
MODES RECLAIM POLICY STATUS CLAIM
STORAGECLASS REASON AGE
task-pv-volume 5Gi RWO
Retain Available
3s

B. vim task-pv-volume.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: task-pv-volume
labels:
type: local
spec:
storageClassName: ""
capacity:
storage: 5Gi
accessModes:
- ReadWriteOnce
hostPath:
path: "/mnt/data"
kubectl apply -f task-pv-volume.yaml
//Verify
kubectl get pv
NAME CAPACITY ACCESS
MODES RECLAIM POLICY STATUS CLAIM
STORAGECLASS REASON AGE
task-pv-volume 4Gi RWO
Retain Available
8s