i'm using ec2-instance from aws and i've done the setup for kubernetes cluster of two nodes. i'm learning about kubernetes multicontainer-pod and in order to do the lab, i need to run two containers is the pod file.

Let me show you the file

apiVersion: v1
kind: Pod
metadata:
  name: multicontainer
spec:
  containers:
  - name: 1st
    image: nginx
    args: ["sleep", "3600"]

  - name: 2nd
    image: nginx

by executing the command

kubectl apply -f multicontainer-pod.yml

we get the pods and these are the two pods. Now i get into the pods by executing the command as

kubectl exec -it multicontainer -c 1st -- /bin/bash

Here in the container i'm executing the command to update the libraries

apt-get update

and stuck with this error

Err:1 http://deb.debian.org/debian buster InRelease
  Temporary failure resolving 'deb.debian.org'
Err:2 http://security.debian.org/debian-security buster/updates InRelease
  Temporary failure resolving 'security.debian.org'
Err:3 http://deb.debian.org/debian buster-updates InRelease
  Temporary failure resolving 'deb.debian.org'
Reading package lists... Done
W: Failed to fetch http://deb.debian.org/debian/dists/buster/InRelease  Temporary failure resolving 'deb.debian.org'
W: Failed to fetch http://security.debian.org/debian-security/dists/buster/updates/InRelease  Temporary failure resolving 'security.debian.org'
W: Failed to fetch http://deb.debian.org/debian/dists/buster-updates/InRelease  Temporary failure resolving 'deb.debian.org'
W: Some index files failed to download. They have been ignored, or old ones used instead.

i even can't write a file as it goes that package not installed.

Out side of this container, i can ping google as well as install the packages but in nginx container, i'm facing this error. kindly help me out ... Thanks