Halo Valeri, let's think about what a hpc cluster is for. Second, one should always ask the question where security is to be applied,then one can come to the following decision: - The firewall is placed in front of the cluster. - After you have found a safe base for this, you freeze it. - We have a rsync of centos and epel on the head node. >From here, we can always reinstall a node (tftp / http) - To relieve the internal network printing, I create rpm packages that are installed on the nodes. All this happened about 3 years ago. Centos 1511 was established as a stable variant for the environment. It was one of my many different tasks in my work. The physicists and mathematicians who count there need high durations. My decision much on Centos because: - free - Maintaining until the year 2024, longer than the cluster will live. My way in the beginning was hard, because I had to learn everything from the scratch and I'm no longer the youngest, but my feeling gave me right. Sincerely Andy