Below are instructions on how to install configure a Percona DB Cluster on Ubuntu (14.04 at time of writing this).

*Carry out on all nodes (servers)

Remove apparmor as it prevents cluster nodes talking to each other:

sudo /etc/init.d/apparmor stop
sudo update-rc.d -f apparmor remove
sudo apt-get remove apparmor apparmor-utils -y

Disable SELinux by editing /etc/selinux/config and add/alter line to disable it:

SELINUX=disabled

Add the following keys to the repository:

apt-key adv –keyserver keys.gnupg.net –recv-keys 1C4CBDCDCD2EFD2A

Add Percona sources:

vim /etc/apt/sources.list
deb http://repo.percona.com/apt trusty main
deb-src http://repo.percona.com/apt trusty main