I'm sorry but 512MB is too little for GitLab, as said on https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/install/requirements.md#memory https://gitlab.c

I'm sorry but 512MB is too little for GitLab, as said on https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/install/requirements.md#memory https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/inst... "we strongly advise against this amount of memory"