Dear, on our stack (1 master -> 20-30 slave around) we have some nodes with very old os (like centos 6) and not upgradable in any ways. So: if in that stack we upgrade only the master server and the others slave node, the legacy one (for example with centos 6) still will works as usual? Or best to have all the server of the same stack with the same version of ispconfig installed over? ty
It can break things, because new options are visible in the panel but won't work, and vice versa. You should always run the same ISPConfig version on every server.
That's exactly why I run debian (or debian-based) systems, you can perform major OS updates without starting everything from scratch each time. There are of course pro's and con's to each. You might consider starting a new ISPConfig installation with up-to-date OS's, and migrate sites/domains which reside on your outdated servers to it (the migration tool makes that a lot easier). Once you have everything off one old server, you can remove it from the old ISPConfig install to keep the total # of servers roughly the same (or less, if your new ones have more resources).
