Monitor file system events to restart service on every configuration change.
numfmt command-line utility which is a part of the standard GNU Core Utilities to pretty print decimal or binary numbers.
varnishlog to log specific Varnish requests.
Varnish Shared memory Log can put a major strain on the disk (I/O write operations). The solution is to store it on the virtual memory filesystem.
needrestart utility to determine which services need to be restarted after the upgrade.
Install the Advanced Open Source Enterprise Wiki.
Use FUSE (filesystem in userspace) to access rdiff-backup repository.
rc.local shell script during boot using systemd compatibility generator.