下記は全てrootで実行します
sudo su -
echo "deb http://repo.mongodb.org/apt/ubuntu trusty/mongodb-org/3.0 multiverse" > /etc/apt/sources.list.d/mongodb-org-3.0.list
echo "deb http://repo.pritunl.com/stable/apt trusty main" > /etc/apt/sources.list.d/pritunl.list
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv 7F0CEB10
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com --recv CF8E292A
apt-get --assume-yes update
apt-get --assume-yes upgrade
apt-get --assume-yes install pritunl mongodb-org
service pritunl start