Github: Using multiple deploy keys

This tutorial will cover how to use multiple deploy keys with Github on a Linux/Mac system.

The first repository with deploy key

To use a repository with a deploy key first check if you have an id_rsa.pub file

ls -l ~/.ssh

if there is a key created you will see a result like this:

ls -l ~/.ssh/
total 40
-rw------- 1 jonasg domain^users  2610 nov 20 10:26 ceep_rsa
-rw-r--r-- 1 jonasg domain^users   580 nov 20 10:26 ceep_rsa.pub
-rw-r--r-- 1 jonasg domain^users   117 nov 20 10:27 config
-rw------- 1 jonasg domain^users  3389 out  4 14:34 id_rsa
-rw-r--r-- 1 jonasg domain^users   752 out  4 14:34 id_rsa.pub
-rw-r--r-- 1 jonasg domain^users 11272 nov 19 09:42 known_hosts

In the example above I have 2 different keys, one id_rsa, and another ceep_rsa. Each key is composed of a rsa file and a rsa_pub file.

For creating or first "deploy key" we will use the id_rsa.pub file. Copy the content of the command:

cat ~/.ssh/id_rsa.pub

And on your Github repository, access Settings / Deploy keys / Add deploy key. Past the key on the Key field, give it a name in the field Title, and check the permission to write to be able to push to this repository.

Adding a second deploy key

Create a new ssh key:

ssh-keygen 
Generating public/private rsa key pair.
Enter file in which to save the key (/home/jonasg/.ssh/id_rsa): /home/jonasg/.ssh/second_rsa
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 

This will create a new pair of files named second_rsa and second_rsa.pub. Copy the second_rsa.pub content and paste it on Github Deploy key of the second repository on Settings / Deploy keys / Add deploy key.

Now it will be necessary to create a config file for our keys:

vi ~/.ssh/config

And add the configuration below:

Host repositoryOne.github.com
  HostName github.com
  User git
  IdentityFile /home/jonasg/.ssh/id_rsa
  IdentitiesOnly yes

Host repositoryTwo.github.com
  HostName github.com
  User git
  IdentityFile /home/jonasg/.ssh/second_rsa
  IdentitiesOnly yes

And on local git repository:

vi "local_repository"/.git/config

Change the value of URL replacing only the repositoryTwo part. The end result will be something like '[e-mail]:your-repository-path'

[core]
        repositoryformatversion = 0
        filemode = true
        bare = false
        logallrefupdates = true
[remote "origin"]
        url = [e-mail]:jonas-gerosa361-react/ceep.git
        fetch = +refs/heads/*:refs/remotes/origin/*

Now you will be able to push to both repositories without passing user and password. For adding more repository just follow the same proccess for them.

Have fun :)