ref:https://kubernetes.io/docs/concepts/workloads/pods/pod-lifecycle/

but the cmd result is(pod:two-containers status is NotReady ):

[root@devnet-master ~]# kubectl get pods
NAME                             READY   STATUS     RESTARTS   AGE
busybox-1                        1/1     Running    1          33d
local-volume-provisioner-k49c7   1/1     Running    0          29m
nginx                            2/2     Running    1          21m
two-containers                   1/2     NotReady   0          61m

the version is:

[root@devnet-master ~]# kubectl version
Client Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.1", GitCommit:"5e58841cce77d4bc13713ad2b91fa0d961e69192", GitTreeState:"clean", BuildDate:"2021-05-12T14:18:45Z", GoVersion:"go1.16.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.1", GitCommit:"5e58841cce77d4bc13713ad2b91fa0d961e69192", GitTreeState:"clean", BuildDate:"2021-05-12T14:12:29Z", GoVersion:"go1.16.4", Compiler:"gc", Platform:"linux/amd64"}

describe pod result is : exec describe pod result image

apply yaml is: apply yaml image

apiVersion: v1
kind: Pod
metadata:
  name: two-containers
spec:
  restartPolicy: Never
  volumes:
  - name: shared-data
    hostPath:      
      path: /data
  containers:
  - name: nginx-container
    image: xxxxxx/nginx:1.0
    volumeMounts:
    - name: shared-data
      mountPath: /usr/share/nginx/html
  - name: debian-container
    image: xxxxxx/debian:stable
    volumeMounts:
    - name: shared-data
      mountPath: /pod-data
    command: ["/bin/sh"]
    args: ["-c", "echo Hello from the debian container > /pod-data/index.html"]