Чтобы установить Varnish на Ubuntu
sudo apt-get update; apt-get install curl nano
sudo curl http://repo.varnish-cache.org/debian/GPG-key.txt | sudo apt-key add -
sudo echo "deb http://repo.varnish-cache.org/ubuntu/ precise varnish-3.0" | sudo tee -a /etc/apt/sources.list
sudo apt-get update; apt-get install varnish