Edit file /home/gitlab/gitlab/config/unicorn.rb
Find line listen "#{app_dir}/tmp/sockets/gitlab.socket"
and comment it.
Uncomment line listen "127.0.0.1:8080"
sudo a2enmod proxy
sudo a2enmod proxy_balancer
sudo a2enmod proxy_http
sudo a2enmod rewrite
You do not need a load balancer to make this work.
You can simply use proxy pass:
(https://gist.github.com/steve-todorov/4758707)