Deploying into linux containers (lxc) as of 2013 before docker even was da hype.

(Experience was a bit problematic tho, as it was in a highly virtualized environment whose backup would really badly kill the whole container every now and then: you could still ssh to the machine but with every access to the file system you'd lose your shell. and only the "echo 1 > /proc/sys/kernel/sysrq" would help to restart the box.)