Eu encontrei o seguinte no stderr
I, [2014-08-19T22:10:48.807830 #3843] INFO -- : Refreshing Gem list
I, [2014-08-19T22:10:53.127464 #3843] INFO -- : listening on addr=127.0.0.1:8080 fd=11
I, [2014-08-19T22:10:53.127774 #3843] INFO -- : unlinking existing socket=/var/opt/gitlab/gitlab-rails/tmp/sockets/gitlab.socket
I, [2014-08-19T22:10:53.127900 #3843] INFO -- : listening on addr=/var/opt/gitlab/gitlab-rails/tmp/sockets/gitlab.socket fd=12
E, [2014-08-19T22:10:53.195390 #3843] ERROR -- : Cannot allocate memory - fork(2) (Errno::ENOMEM)
Então, presumo que tenho memória insuficiente ... tenho 512 MB
Encontrei isso no gitlabHq
512MB is the absolute minimum but we do not recommend this amount of memory. You will either need to configure 512MB or 1.5GB of swap space. With 512MB of swap space you must configure only one unicorn worker. With one unicorn worker only git over ssh access will work because the git over http access requires two running workers (one worker to receive the user request and one worker for the authorization check). If you use SSD storage and configure 1.5GB of swap space you can use two Unicorn workers, this will allow http access but it will still be slow. 1GB supports up to 100 users (we highly recommend adding al least 1GB of swap space, this is a must if you have individual repositories under 250MB)