Upgrade elasticsearch 3x node( init scripts ) per host cluster


I read the instructions about upgrading cluster:

I have still few questions:

Lets say that I have 2 hosts and on every host I installed 3 elasticsearch nodes (Every node have own elasticsearch.yml and init scirpt).

How should properly look like upgrade of the cluster?

Should I:
1.) Stop shard allocation
2.) Stop 3 nodes of elastic on that host
3.) Upgrade elasticsearch
4.) Start service es1, es2, es3
5.) Wait for status green of cluster.

After that should I do the same with second host?

any advice ?