Recently I had a challenge of getting capistrano deployments working from jenkins installed on a RHEL box. The problem seemed to be down to the fact that ssh-agent isn’t running for the daemon process that jenkins runs as for whatever reason and it is needed to do ssh agent forwarding (which is what I do so I can use the ssh key on the jenkins server to check code out from github on remote servers).
After banging my head against the head for a couple hours, I came up with a simple solution: execute a shell script through ssh-agent. I simply created a deploy.sh script in the root of my project with the following contents:
!#/bin/sh ssh-add cap $1 deploy
Then execute it through ssh agent.
exec /usr/bin/ssh-agent "${WORSKPACE}/deploy.sh" "production"
Works perfectly. Hopefully this helps someone else, took me a lot of grief to figure this out.
Oh yeah, in case you didn’t know, I’m back in PHP development again for awhile so there should be some interesting posts ahead. 
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