How to SSH agent forward into a docker container

docker-ssh-forward.bash

docker run -rm -t -i -v $(dirname $SSH_AUTH_SOCK) -e SSH_AUTH_SOCK=$SSH_AUTH_SOCK ubuntu /bin/bash

In order for this to work you need to specify volume like so:

docker run -rm -t -i -v $(dirname $SSH_AUTH_SOCK):$(dirname $SSH_AUTH_SOCK) -e SSH_AUTH_SOCK=$SSH_AUTH_SOCK ubuntu /bin/bash

In order for this to work you need to specify volume like so:

docker run -rm -t -i -v $(dirname $SSH_AUTH_SOCK):$(dirname $SSH_AUTH_SOCK) -e SSH_AUTH_SOCK=$SSH_AUTH_SOCK ubuntu /bin/bash

docker run --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ubuntu ssh-add -l

docker run --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ubuntu ssh-add -l

Wow, I was wondering how this solutions works with socket file share, it wasn't supposed to work though. But then again, now I realise that docker containers share same kernel level with the guest OS. Good tips 👍

Wow, I was wondering how this solutions works with socket file share, it wasn't supposed to work though. But then again, now I realise that docker containers share same kernel level with the guest OS. Good tips 👍

Is there any pre-requisite for the Docker host? My host can connect to a SSH server using private key authentication just fine, but the container fails to find a private key (which makes sense since it doesn't have it) and fallbacks to password authentication...

Is there any pre-requisite for the Docker host? My host can connect to a SSH server using private key authentication just fine, but the container fails to find a private key (which makes sense since it doesn't have it) and fallbacks to password authentication...

I can’t see how this would work, given that the permissions on $SSH_AUTH_SOCK in the host won’t allow access from the container user? I must be missing something? :/

I can’t see how this would work, given that the permissions on $SSH_AUTH_SOCK in the host won’t allow access from the container user? I must be missing something? :/

This exposes the value of the $SSH_AUTH_SOCK (whichiis the path to a socket file on the host) as a volume into the docker container (at the location /ssh-agent). Inside the container you then set the environment variable $SSH_AUTH_SOCK with the path to the volume inside, /ssh-agent). Since this environment variable is now set, ssh-agent -l can make use of it inside the container. When you run these commands inside the docker container you're root and so you have access.

This exposes the value of the $SSH_AUTH_SOCK (whichiis the path to a socket file on the host) as a volume into the docker container (at the location /ssh-agent). Inside the container you then set the environment variable $SSH_AUTH_SOCK with the path to the volume inside, /ssh-agent). Since this environment variable is now set, ssh-agent -l can make use of it inside the container. When you run these commands inside the docker container you're root and so you have access.

If you're running this command in a Vagrant created VM, you might have problems with the file in $SSH_AUTH_SOCK being a symlink, so this worked for me:

docker run -i -t -v $(readlink -f $SSH_AUTH_SOCK):/ssh-agent -e SSH_AUTH_SOCK=/ssh-agent ubuntu /bin/bash

If you're running this command in a Vagrant created VM, you might have problems with the file in $SSH_AUTH_SOCK being a symlink, so this worked for me:

docker run -i -t -v $(readlink -f $SSH_AUTH_SOCK):/ssh-agent -e SSH_AUTH_SOCK=/ssh-agent ubuntu /bin/bash

Anyone get this to work in boot2docker yet?

Anyone get this to work in boot2docker yet?

+1 @arunthampi That works very well in my Vagrant+Docker setup. I was using a Docker container to run Capistrano commands, so I had a few other things. I needed to add a --env CAP_USER=$CAP_USER and then in my Vagrant VM .bashrc source a file that contained my remote CAP_USER username.

File /home/vagrant/.cap_user contains just remote-user
Then in file: /home/vagrant/.bashrc I have a line like this:

    test -f ~/.cap_user && export CAP_USER=$(cat ~/.cap_user) || true

I set that file up in the VM using the Vagrantfile shell provisioner to copy both files into the VM.

Viola. Capistrano deploying happening inside a Docker container.

+1 @arunthampi That works very well in my Vagrant+Docker setup. I was using a Docker container to run Capistrano commands, so I had a few other things. I needed to add a --env CAP_USER=$CAP_USER and then in my Vagrant VM .bashrc source a file that contained my remote CAP_USER username.

File /home/vagrant/.cap_user contains just remote-user
Then in file: /home/vagrant/.bashrc I have a line like this:

    test -f ~/.cap_user && export CAP_USER=$(cat ~/.cap_user) || true

I set that file up in the VM using the Vagrantfile shell provisioner to copy both files into the VM.

Viola. Capistrano deploying happening inside a Docker container.

@tobowers: Works for me on boot2docker on mac, but I have to do it in two steps, SSH into the host VM, then run @arunthampi's code. Like so:

 $ boot2docker ssh
 $ docker run -i -t -v $(readlink -f $SSH_AUTH_SOCK):/ssh-agent -e SSH_AUTH_SOCK=/ssh-agent ubuntu /bin/bash

Once you're in to the host VM, you can check out forwarding status with ssh-add -L. If you get the publickeys you expect, proceed into the container.

@tobowers: Works for me on boot2docker on mac, but I have to do it in two steps, SSH into the host VM, then run @arunthampi's code. Like so:

 $ boot2docker ssh
 $ docker run -i -t -v $(readlink -f $SSH_AUTH_SOCK):/ssh-agent -e SSH_AUTH_SOCK=/ssh-agent ubuntu /bin/bash

Once you're in to the host VM, you can check out forwarding status with ssh-add -L. If you get the publickeys you expect, proceed into the container.

@dts You forgot -A.

$ boot2docker ssh -A
$ ssh-add -l
2048 97:f0:e8:b3:c6:cb:2b:06:93:31:f5:a5:c6:0c:22:07 /Users/alan/.ssh/id_rsa (RSA)
$ docker run -i -t -v $(readlink -f $SSH_AUTH_SOCK):/ssh-agent -e SSH_AUTH_SOCK=/ssh-agent ubuntu /bin/bash
$ apt-get -q=2 update && apt-get -q=2 install ssh > /dev/null 2>&1
$ ssh-add -l
2048 97:f0:e8:b3:c6:cb:2b:06:93:31:f5:a5:c6:0c:22:07 /Users/alan/.ssh/id_rsa (RSA)

@dts You forgot -A.

$ boot2docker ssh -A
$ ssh-add -l
2048 97:f0:e8:b3:c6:cb:2b:06:93:31:f5:a5:c6:0c:22:07 /Users/alan/.ssh/id_rsa (RSA)
$ docker run -i -t -v $(readlink -f $SSH_AUTH_SOCK):/ssh-agent -e SSH_AUTH_SOCK=/ssh-agent ubuntu /bin/bash
$ apt-get -q=2 update && apt-get -q=2 install ssh > /dev/null 2>&1
$ ssh-add -l
2048 97:f0:e8:b3:c6:cb:2b:06:93:31:f5:a5:c6:0c:22:07 /Users/alan/.ssh/id_rsa (RSA)

@tobowers On boot2docker Just your home dir is available on boot2docker-vm, maybe if you symlink the ssh-agent socket to $HOME/something this can work.

@tobowers On boot2docker Just your home dir is available on boot2docker-vm, maybe if you symlink the ssh-agent socket to $HOME/something this can work.

I'm trying this, but with docker-compose. I was typing a comment, but too much for this gist. Any help is appreciated over on http://stackoverflow.com/questions/32897709/ssh-key-forwarding-inside-docker-compose-container

I'm trying this, but with docker-compose. I was typing a comment, but too much for this gist. Any help is appreciated over on http://stackoverflow.com/questions/32897709/ssh-key-forwarding-inside-docker-compose-container

Great thanks.

docker run --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ubuntu ssh-add -l

Works pretty well!

Great thanks.

docker run --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ubuntu ssh-add -l

Works pretty well!

Has anyone managed to use SSH agent forwarding in combination with running the container as a different user e.g. docker run -u $(id -u):$(id -g) --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ...?

SSH actually checks that the effective UID is present in the password database and fails with You don't exist, go away! otherwise.

Has anyone managed to use SSH agent forwarding in combination with running the container as a different user e.g. docker run -u $(id -u):$(id -g) --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ...?

SSH actually checks that the effective UID is present in the password database and fails with You don't exist, go away! otherwise.

I get the following error when trying this out. I'm using a mac and have tried this on both docker for mac and docker-machine. I had to first install git on the ubuntu image.

docker run --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ubuntu ssh-add -l                             ✹ ✭
Error connecting to agent: Connection refused

I get the following error when trying this out. I'm using a mac and have tried this on both docker for mac and docker-machine. I had to first install git on the ubuntu image.

docker run --volume $SSH_AUTH_SOCK:/ssh-agent --env SSH_AUTH_SOCK=/ssh-agent ubuntu ssh-add -l                             ✹ ✭
Error connecting to agent: Connection refused

@whistler, sharing the auth socket is currently not working for docker for mac, see:
docker/for-mac#410

It seems there is a work in progress that should be available before the end of November:
docker/for-mac#483

@whistler, sharing the auth socket is currently not working for docker for mac, see:
docker/for-mac#410

It seems there is a work in progress that should be available before the end of November:
docker/for-mac#483

@gautaz thanks for the heads up!

@gautaz thanks for the heads up!

What if I have Windows? How to use SSH_AUTH_SOCK?

I can clone repo with common git for WIndows, but not inside the container

What if I have Windows? How to use SSH_AUTH_SOCK?

I can clone repo with common git for WIndows, but not inside the container

It would very helpfull to get a clarification on how to share ssh keys when the hots is windows (maybe by a key copy..)

It would very helpfull to get a clarification on how to share ssh keys when the hots is windows (maybe by a key copy..)

@Sylvain, give a chance to WSL (Windows Subsystem for Linux).

@Sylvain, give a chance to WSL (Windows Subsystem for Linux).

@kynan if you aren't using a remote user database for your system (eg LDAP/AD) you can map in /etc/passwd read-only so SSH can find your user.

@kynan if you aren't using a remote user database for your system (eg LDAP/AD) you can map in /etc/passwd read-only so SSH can find your user.

Maybe, there is similar way to integrate gpg into docker container?

Maybe, there is similar way to integrate gpg into docker container?