Which is the simplest way to "isolate" Apache virtual sites, so that a potentially compromised site doesn't affect the other sites or the server?
To be clear, I am not interested much is scalability, portability, etc, just how to insulate a few small sites currently running as Apache virtual hosts in a relatively powerful home-server that does other things as well (file server, media server,...), so docker solutions seems a bit over the top..
If you're looking for decent compartmentalisation, then Docker or a Virtual Machine would be the way to go, as this would ensure that the Apache processes could only write to their own confined area and not to other locations writable by the Apache user. However, as the relatively powerful home server would still need to route traffic to those instances, there is always the possibility of an external entity compromising the entry point to the system.