use ssh private key from host in vagrant guest

Question

I want to clone a bunch of private git repositories while provisioning a vagrant box. According to this article this should be possible using config.ssh.forward_agent = true. However, when trying to connect to github via something like ssh -T [email protected] -o StrictHostKeyChecking=no it fails with the following error:

Warning: Permanently added 'github.com,192.30.252.130' (RSA) to the list of known hosts. Permission denied (publickey).

I cut my configuration down to the simplest possible configuration. You can find it here: https://gist.github.com/TomTasche/31f7c45fcffc2997d43a

When I do "vagrant ssh" and try the same again, a similar error occurs:

Cloning into 'private-repositories'... Warning: Permanently added the RSA host key for IP address '192.30.252.130' to the list of known hosts. Permission denied (publickey). fatal: The remote end hung up unexpectedly

Edit: the configuration linked above does work on a host running Ubuntu, but does neither work on a Mac host, nor on a Windows host. My goal is to have a configuration that works on all these three hosts.

Answer 1

Please check whether your host system has ssh-agent forwarding enabled. You can do so for example by adding this block to your ~/.ssh/config file:

Host                    *
  ForwardAgent          yes 

If this is enabled vagrant ssh (and also vagrant provision) should be able to forward your key to the guest machine.

You also might want to check using ssh-add -l whether your ssh-agent does know about your SSH-key. If it is in the list and you have agent-forwarding activated you should have a success. Otherwise you can add the key to your ssh-agent by running ssh-add <path to your key file>.