Here’s a scenario: you want to use multiple GitLab (or GitHub, etc.) on your machine. One could be your personal account and another one you use specifically for work. You want to use different SSH keys to access the repositories in either account.
Here’s how to achieve that setup properly. For this article, let’s assume we have the two GitLab accounts:
- Personal Account, username:
personal, email:personal@email.com - Work Account, username:
work, email:work@email.com
GitLab does not allow you to use the same SSH key in multiple accounts, so you’ll have to create separate keys for each account. You can create SSH keys and add them to your SSH agent by following this guide from the GitHub Documentation.
Once you’re done, you will have two sets of SSH keys, e.g.:
~/.ssh/personal_keyand~/.ssh/personal_key.pub~/.ssh/work_keyand~/.ssh/work_key.pub
Now add the SSH keys to their corresponding GitLab accounts. You may follow this guide on how to do that.
Now create the file ~/.ssh/config and add the following contents:
Host gitlab.com
HostName gitlab.com
User git
IdentityFile ~/.ssh/personal_keyHost gitlab.com-work
HostName gitlab.com
User git
IdentityFile ~/.ssh/work_key
This tells SSH to use the ~/.ssh/personal_key identity by default when interacting with gitlab.com, unless the host used is “gitlab.com-work” in which case the ~/.ssh/work_key identity will be used.
The value for the Host directive can actually be anything, I’m just following a naming convention of {original-host}-{username} to make it more memorable.
When cloning repositories from the work account, you’ll need to modify the URL’s host to match the value in the SSH config’s Host directive. For example:
# Before
$ git clone git@gitlab.com:work/repository.git# After
$ git clone git@gitlab.com-work:work/repository.git
Updating existing repositories
If you already have a local copy of the repository and you want to update their remotes to point to your remote work repository, you can do so by updating the remote’s URL like so (assuming your remote’s name is origin):
$ git remote set-url origin git@gitlab.com-work:work/repository.gitWhen making commits, git will look at the configs to determine the name and email that it will use as the commit’s author. This will most likely end up being your global git config. To override the global config on a per-project basis, you can do:
$ cd work-repository
$ git config user.name "Work Account"
$ git config user.email "work@email.com"Notice the absence of the —-global flag. These configs will only be set inside repository in which they were executed. When moving to other repositories, their local git configs (or the global config if no local config is set) will be used. This will keep you from having to modify your global git config every time you go inside a git repository.
Update Dec 12, 2017 11:02 am: As pointed out by Mary Louise Hermosa in the responses, an alternative approach to setting local git configs is to use “Conditional Includes”. To use it, you need to add the following snippet to your ~/.gitconfig file:
[includeIf "gitdir:/path/to/work-repository/"]
[user]
name = Work Account
email = work@email.comThis dynamically adds/removes git configs based on which git repository you are on. An advantage of this is that you can manage git configs for different projects in one central location, the ~/.gitconfig file.
