Q1: What is the use of docker update command with example and image?

The docker update command dynamically updates container configuration like cpu, memory etc.

To specify more than one container, provide space-separated list of container names or IDs.

		root@ip-172-31-28-155:/home/ubuntu# docker stats | egrep "CONTAINER|anoop_ubuntu_mem"
		CONTAINER ID   NAME                         CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O         PIDS
		ae8459944595   anoop_ubuntu_mem             0.00%     3.781MiB / 2GiB       0.18%     1.23kB / 0B       0B / 0B           3

		root@ip-172-31-28-155:/home/ubuntu# docker update --memory "5g" ae8459944595
		ae8459944595
		Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
		
		root@ip-172-31-28-155:/home/ubuntu# docker stats | egrep "CONTAINER|anoop_ubuntu_mem"
		CONTAINER ID   NAME                         CPU %     MEM USAGE / LIMIT     MEM %     NET I/O           BLOCK I/O         PIDS
		ae8459944595   anoop_ubuntu_mem             0.00%     3.781MiB / 5GiB       0.07%     1.23kB / 0B       0B / 0B           3