How to Update Hosts file in instance so they can communicate by the DN?

Question

Amazon Web Services

The task is to create a playbook so that you can update the host file so that several instances can communicate by domain name. I don’t understand how this can be done

Answer 1

yes, they should be assigned names in DNS, this is correct and very simple and there is no need to fence the garden

Answer 2

Roll up "address - name" pairs in /etc/hosts, what can cause problems here?
do you know the names? do you know the address?
make a list and go.