Useful SSH guide
~/.ssh/config
Set your config like so:
Host gitlab
HostName gitlab.domain.com
User git
IdentityFile ~/.ssh/your-private-key
HostName gitlab.domain.com
IdentityFile ~/.ssh/your-private-key
Now you can use it like so:
git remote set-url origin git@gitlab.domain.com:/group1/group2/yourlibrepo
Or:
git remote set-url origin gitlab:/group1/group2/yourexerepo