Push a Git repo to multiple remotes with unique SSH keys

For one reason or another, you might like to push a Git repo to more than one remote. This website automatically gets pushed to both Codeberg and Github, for example.

Here, I will discuss how I’ve set things up.

Managing multiple SSH keys

With SSH, you can securely push changes to your Git remotes without needing to enter login credentials every time. For a single repository, there is minimal setup: just upload your public key.

To use unique keys for different repos calls for a few extra steps.

Create one for Github:

ssh-keygen -t ed25519 -f ~/.ssh/gomarcd-github

And another for Codeberg:

ssh-keygen -t ed25519 -f ~/.ssh/gomarcd-codeberg

Now let’s add an SSH configuration for each one:

$ sudo nano ~/.ssh/config

Host gomarcd.github.com
    Hostname github.com
    User gomarcd
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/gomarcd-github
    IdentitiesOnly yes

Host gomarcd.codeberg.org
    Hostname codeberg.org
    User gomarcd
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/gomarcd-codeberg
    IdentitiesOnly yes

See the new keypairs with:

$ ls ~/.ssh | grep gomarcd

gomarcd-codeberg
gomarcd-codeberg.pub
gomarcd-github
gomarcd-github.pub

It’s a good idea to back these up in a safe place.

Next, upload each respective public key (file ending in .pub) to Github & Codeberg.

Git configuration

Initialize your Git repo and switch to main branch:

$ cd /home/gomarcd/dev/newProject
$ git init && git branch -m main

We switch to main because it’s often default now, but you should use whatever branch your remote will be expecting.

Make sure Git remote config includes the SSH host:

$ nano .git/config

[core]
        repositoryformatversion = 0
        filemode = true
        bare = false
        logallrefupdates = true
[remote "origin"]
        url = [email protected]:gomarcd/newproject.git
        fetch = +refs/heads/*:refs/remotes/origin/*
        url = [email protected]:gomarcd/newproject.git
[branch "main"]
        remote = origin
        merge = refs/heads/main
[user]
        name = gomarcd
        email = [email protected]

Also note the gomarcd.github.com is only a reference to the SSH identity and must match what you put as Host from ~/.ssh/config.

All that’s left now is to create a repo with the same name in Github & Codeberg!

From now on, git push will automatically push to both repositories using their respective SSH keys.