If you are setting up multiple certificates to connect to Bitbucket from a single Jenkins instance, the first key will end up as the default private/public key (for example, id_rsa is already associated with “bitbucket.org”), so you need to use an alias (bitbucket-username). The process is well documented – Configure multiple SSH identities for GitBash, Mac OSX, & Linux.

1. Create private/public key pair as jenkins using a passphrase.
2. Added the public key to bitbucket.
3. Added this to /var/lib/jenkins/.ssh/config:

   Host bitbucket-username
     HostName bitbucket.org
     User git
     IdentityFile /var/lib/jenkins/.ssh/id_rsa_username

The ssh url

• Original URL
  • git@bitbucket.org:accountname/reponame.git
• New URL
  • git@alias:accountname/reponame.git
  • git@bitbucket-username:accountname/reponame.git

In this scenario, every time I ssh into Bitbucket using the jenkins user, I am prompted to enter the passphrase. The ssh-agent comes into picture to save this passphrase and use ssh without being prompted every time.

• Couple of resources for ssh-agent and all that:
  • http://joncairns.com/2013/12/understanding-ssh-agent-and-ssh-add/
  • https://github.com/funtoo/keychain

The Jenkins SSH Agent Plugin solves this problem..