Installation on Debian
Varnish is distributed in the Debian package repositories but the version there might be out of date and we generally recommend using the packages provided by varnish-cache.org or packages from backports.debian.org.
To use the varnish-cache.org repository and install Varnish under Debian 8 ("jessie") do the following as root:
apt-get install apt-transport-https
curl https://repo.varnish-cache.org/GPG-key.txt | apt-key add -
echo "deb https://repo.varnish-cache.org/debian/ jessie varnish-4.1" >> /etc/apt/sources.list.d/varnish-cache.list
apt-get install varnish
Packages are built for wheezy and jessie on amd64. Varnish 4.0 packages are available in the "varnish-4.0" component.
Ubuntu LTS users please follow these instructions.