Using ssh-agent with docker on macOS

Question

I would like to use ssh-agent to forward my keys into the docker image and pull from a private github repo.

I am using a slightly modified version of https://github.com/phusion/passenger-docker with boot2docker on Yosemite.

ssh-add -l
...key details
boot2docker up

Then I use the command which I have seen in a number of places (i.e. https://gist.github.com/d11wtq/8699521):

docker run --rm -t -i -v $SSH_AUTH_SOCK:/ssh-agent -e SSH_AUTH_SOCK=/ssh-agent my_image /bin/bash

However it doesn't seem to work:

root@299212f6fee3:/# ssh-add -l
Could not open a connection to your authentication agent.

root@299212f6fee3:/# eval `ssh-agent -s`
Agent pid 19

root@299212f6fee3:/# ssh-add -l
The agent has no identities.

root@299212f6fee3:/# ssh [e-mail]
Warning: Permanently added the RSA host key for IP address '192.30.252.128' to the list of known hosts.
Permission denied (publickey).

Answer 1

A one-liner:

Here’s how to set it up on Ubuntu 16 running a Debian Jessie image:

docker run --rm -it --name container_name \
-v $(dirname $SSH_AUTH_SOCK):$(dirname $SSH_AUTH_SOCK) \
-e SSH_AUTH_SOCK=$SSH_AUTH_SOCK my_image

https://techtip.tech.blog/2016/12/04/using-ssh-agent-forwarding-with-a-docker-container/

Answer 2

Since version 2.2.0.0, docker for macOS allows users to access the host’s SSH agent inside containers.

Here's an example command that let's you do it:

docker run --rm -it \
-v /run/host-services/ssh-auth.sock:/ssh-agent \
-e SSH_AUTH_SOCK="/ssh-agent" \
my_image

Note that you have to mount the specific path (/run/host-services/ssh-auth.sock) instead of the path contained in $SSH_AUTH_SOCK environment variable, like you would do on linux hosts.