Setting up multiple SSH key access to Github

Question

I'm trying to configure a remote linux machine to access two distinct git accounts which I own. I keep getting authentication access manifesting in.

> git push
ERROR: Repository not found.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

Steps i've taken,

1. Generated a two sets of ssh keys (call them key1 and key2)
2. Generated a config file at ~/.ssh/config
3. Edited that file

    1 # Default github account: key1
      2 Host github.com
      3    HostName github.com
      4    IdentityFile ~/.ssh/key1
      5    IdentitiesOnly yes
      6
      7 # Other github account: key2
      8 Host github-key2
      9    HostName github.com
     10    IdentityFile ~/.ssh/key2
     11    IdentitiesOnly yes

4. Added the .pub version to my two git accounts under the user account settings/ssh keys.
5. Added them on my VM with ssh-add ~/.ssh/key1

I'm unsure really where to go from here and what the next steps are for why this isn't working. I feel like there might be a step i'm missing.

Answer 1

tl;dr: Add the following entry to your ~/.ssh/config where $user is the GitHub username and $key is the private key specified for that user and defined in the setting for that GitHub user:

Host github.com-$user
    Hostname github.com
    User git
    IdentityFile ~/.ssh/$key
    IdentitiesOnly yes

Then, configure your git remote URL:

git remote add origin [email protected]$user:$user/$repo

Basically, I had a long-running SSH key for work/personal projects, then wanted to add a new key for unrelated side projects. I did all of the steps you outlined in your question, and still got the same error. Doing $ GIT_SSH_COMMAND='ssh -v' git fetch showed that git was passing my main user's private key first, and even though it was authenticating correctly as a valid key, that user of course had no permissions on the new user's private repositories.

Relevant post: https://medium.com/@ordinary.yobi/multiple-ssh-keys-on-github-f75a372d5374