debian

To install and run Needrestart:

sudo apt-get install needrestart
sudo needrestart

For more info: When to Restart Services or Reboot after Update on Debian or Ubuntu

The program at Github: https://github.com/liske/needrestart

With the latest update of Varnish, the configuration file has moved to a new place. This is how you do it Debian 8 with varnish 4.1.4-1~jessie:

Create folder and insert in /etc/systemd/system/varnish.service.d/customexec.conf:

sudo -i
mkdir /etc/systemd/system/varnish.service.d
vi /etc/systemd/system/varnish.service.d/customexec.conf

By installing Memcached on your server, you can speed up the load time for your web site pages.

From the official web site: "Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.