github deploy keys: how Do I authorize more than one repository for a single machine

Question

So, I have a host, call it rob. I used ssh-keygen on rob to get a public key, which I gave to github in the add a new deploy key screen for repository cheech. Now I want to deploy chong on rob as well. But if I go to the add new deploy key screen for repository chong on github, and paste in the public key I generated on rob it says key already in use. I thought, if they key was in use, I could clone chong on rob but that says permission denied.

So clearly this is more complicated than I thought and it involves having multiple keys or something. What should I do to clone chong on rob?

Thank you for your help.

question from:https://stackoverflow.com/questions/11656134/github-deploy-keys-how-do-i-authorize-more-than-one-repository-for-a-single-mac

Answer 1

Once a key has been attached to one repo as a deploy key, it cannot be used on another repo. If you're running into this error while setting up deploy keys, then you'll need to modify your remote and set up your ~/.ssh/config file to use a non-existent github.com hostname that ssh will be able to use to pick the correct ssh deploy key for your repository.

# first we remove the origin
$ git remote -v
origin  [email protected]:username/foo.git (fetch)
origin  [email protected]:username/foo.git (push)
$ git remote rm origin

# here we add a new origin using a host nickname called
# foo.github.com that we will reference with a Host stanza in our
# ~/.ssh/config to specify which key to use with which fake hostname.
$ git remote add origin [email protected]:username/foo.git
$ git remote -v
origin  [email protected]:username/foo.git (fetch)
origin  [email protected]:username/foo.git (push)

Generate the deploy key for your repository and name it something reasonable like:

$ ssh-keygen -t rsa -f ~/.ssh/id_rsa-foo -C https://github.com/username/foo
Generating public/private rsa key pair.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/username/.ssh/id_rsa-foo.
Your public key has been saved in /home/username/.ssh/id_rsa-foo.pub.
The key fingerprint is:
c0:ff:ee:34:24:11:5e:6d:7c:4c:b1:a0:de:ad:be:ef https://github.com/username/foo
The key's randomart image is:
+--[ RSA 2048]----+
|  E   o..o.oo.   |
| M o o o .+CoW   |
|  + o = o. ..    |
| .   . +         |
|        S        |
|       o .       |
|        +        |
|       . o       |
|        ..o.     |
+-----------------+

Once you've added the deploy key you will then need to add the following stanza to your ~/.ssh/config file:

Host fake-hostname-foo.github.com
    Hostname github.com
    IdentityFile ~/.ssh/id_rsa-foo

Now you can test it with:

$ ssh -T [email protected]
Hi username! You've successfully authenticated, but GitHub
does not provide shell access.