Managing Multiple SSH Keys for Different Git Hosting Platforms (GitLab & GitHub)

If you have multiple GitHub or GitLab accounts, you might run into SSH key conflicts when pushing or pulling repositories. By default, SSH always tries to use the first key it finds, which can lead to permission issues. But don’t worry! In this guide, we’ll set up multiple SSH keys and configure them properly, so you can seamlessly work with multiple accounts on both platforms.

Step 1: Generate SSH Keys for Each Account

If you haven’t already generated SSH keys for each account, you can create them using:

ssh-keygen -t ed25519 -C "[e-mail]" -f ~/.ssh/id_ed25519_first
ssh-keygen -t ed25519 -C "[e-mail]" -f ~/.ssh/id_ed25519_second

This will create two key pairs:

• ~/.ssh/id_ed25519_first (private key) and ~/.ssh/id_ed25519_first.pub (public key)
• ~/.ssh/id_ed25519_second (private key) and ~/.ssh/id_ed25519_second.pub (public key)

Step 2: Add SSH Keys to Git Hosting Platforms

For GitHub:

1. Copy each public key to your clipboard:

   cat ~/.ssh/id_ed25519_first.pub
   cat ~/.ssh/id_ed25519_second.pub

1. Go to GitHub → Settings → SSH and GPG Keys
2. Add each key to the respective GitHub account.

For GitLab:

1. Copy each public key:

   cat ~/.ssh/id_ed25519_first.pub
   cat ~/.ssh/id_ed25519_second.pub

1. Go to GitLab → Settings → SSH Keys
2. Add each key to the respective GitLab account.

Step 3: Configure SSH to Use Different Keys

By default, SSH uses [e-mail] and [e-mail] for all connections, but we can assign different identities using an SSH configuration file.

Edit (or create) the SSH config file:

nano ~/.ssh/config

Then, add the following lines:

Host github-first
    HostName github.com
    User git
    IdentityFile ~/.ssh/id_ed25519_first
    IdentitiesOnly yes

Host github-second
    HostName github.com
    User git
    IdentityFile ~/.ssh/id_ed25519_second
    IdentitiesOnly yes

Host gitlab-first
    HostName gitlab.com
    User git
    IdentityFile ~/.ssh/id_ed25519_first
    IdentitiesOnly yes

Host gitlab-second
    HostName gitlab.com
    User git
    IdentityFile ~/.ssh/id_ed25519_second
    IdentitiesOnly yes

This tells SSH to use different keys based on the hostname alias.

Step 4: Clone Repositories Using the Correct SSH Key

Instead of using [e-mail] or [e-mail], use the custom host from our SSH config:

For GitHub:

git clone github-first:your-first-user/your-repo.git

Or for the second account:

git clone github-second:your-second-user/your-repo.git

For GitLab:

git clone gitlab-first:your-first-user/your-repo.git

Or for the second account:

git clone gitlab-second:your-second-user/your-repo.git

Step 5: Update an Existing Repository’s Remote

If you already cloned a repo with the wrong account, update the remote URL:

git remote set-url origin github-second:your-second-user/your-repo.git

Or for GitLab:

git remote set-url origin gitlab-second:your-second-user/your-repo.git

Step 6: Test Your SSH Connection

To verify which account you’re using, test with:

ssh -T github-first
ssh -T github-second
ssh -T gitlab-first
ssh -T gitlab-second

Each command should return a message identifying the correct user.

Final Thoughts

By configuring your SSH setup correctly, you avoid the headaches of permission issues and seamlessly switch between multiple GitHub and GitLab accounts. This method also works for Bitbucket or any other Git service that relies on SSH authentication.

Now you’re ready to juggle multiple Git accounts like a pro!