GitHub Jenkins Deploy Keys Config

GitHub doesn't let you use the same deploy key for multiple repositories within a single organziation, so you have to either (a) manage multiple keys, (b) create a non-human user (boo!), or (c) use their not-yet-ready for primetime HTTP OAUTH deploy access, which can't create read-only permissions.

In the past to managee the multiple keys I've either (a) used ssh-agent or (b) specified which private key to use for each request using -i on the command line, but neither of those are convenient with Jenkins.

Today I finally thought about it a little harder and figured out I could use fake hostnames that map to the right keys within the .ssh/config file for the Jenkins user. To make it work I put stanzas like this in the config file:

    IdentityFile ~jenkins/keys/repo_name_deploy

Then in the Jenkins GitHub Plugin config I set the repository URL as:

There is no host and it wouldn't resolve in DNS, but that's okay because the .ssh/config tells ssh to actually go to, but we do get the right key.

Maybe this is obvious and everyone's doing it, but I found it the least-hassle way to maintain the accounts-for-people-only rule along with the separate-keys-for-separate-repos rule and without running the ssh-agent daemon for a non-login shell.