Post Made Community Wiki by Paul Sweatte
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SSH Agent forwarding is a potential security risk:

The problem is that while you're connected to host A, a forwarding socket will be set up so that the SSH client on host A can connect to the ssh-agent on your workstation to perform authentication on its behalf. This means that anyone with sufficient permission on host A will be able to use that socket to connect to and use your local ssh-agent. It could be the root user or anyone else who managed to compromise host A. The result is that the user would be able to impersonate you to any host as long as you're connected to host A.

At any rate, if you need to fix this, first check to see if the key is listed:

$ ssh-add -l

Then, if you don't see your key listed, add it by

ssh-add ~/.ssh/identity

And add the public key to gitolite:

On the server you have appended this file to ~/.ssh/authorized_keys. Or you ran something, like the gitolite setup step during a gitolite install, which should have done that for you.