Rocker

Deprecation Notice

This repository is deprecated. As of Docker 18.09, connecting to Docker daemon over SSH is built-in, so this helper script is no longer necessary.

Remote Docker is a small wrapper around the docker client that extends it with support for securely connecting to a remote dockerd daemon via SSH.

In short, it implements the ssh:// protocol for the --host parameter in the Docker CLI.

Why? Because I use a MacBook 12" which is essentially a tablet in laptop form, so offloading the dockerd daemon to a more powerful machine makes development a lot faster. This also allows for an easy way to share running docker containers between teammates for collaboration, or if you develop on more than one machine.

Aims to support all docker features, in particular:

Port publishing (-p) by SSH local port forwarding.
Volume mounts (-v) by a reverse sshfs from the server to local.

Usage

One-time with -H/--host:

$ docker -H ssh://user@myserver.com run --rm -p 80:80 nginx

Make it permanent by setting DOCKER_HOST:

$ export DOCKER_HOST=ssh://user@myserver.com
$ docker run --rm -p 80:80 nginx

Setup

Local

Install the docker client (Docker for Mac for MacOS).
Setup an SSH server running locally, for the reverse sshfs mount to work.
Add the remote docker server's public key to your local ~/.ssh/authorized_keys.
Run ./install.sh from this repo to install /usr/local/bin/docker and friends.
Set the DOCKER_HOST env var or use docker -H with an ssh:// protocol to invoke "rocker".
To avoid getting a Password: prompt every time you invoke docker, you must add to the end of your /etc/sudoers file:
```
# Make `sudo -E rockerd` work without a password
YOUR_USERNAME ALL=(root) NOPASSWD:SETENV: /usr/local/bin/rockerd
```
Be sure to replace YOUR_USERNAME with your actual username, and update the file location if you installed it to a non-default location.

Server

Instructions are for an Ubuntu server:

Setup docker.
Setup SSH server.
Install sshfs:
```
$ sudo apt-get install sshfs
```
Create /mnt/sshfs with full permissions for the user you will log in as.
```
$ sudo mkdir -p /mnt/sshfs
$ sudo chmod 777 /mnt/sshfs
```

Sub-commands

All rockerd commands expect either the DOCKER_HOST environment variable to be set, or for the --host/-H CLI argument to be specified.

SSH into the remote docker machine

$ rockerd ssh

Invokes ssh with the configured docker host. The ssh connection uses the control socket that the rockerd daemon creates, so it does not need to perform a new handshake, etc.

Explicitly forwarding a port to localhost

Publish port 80 from the remote docker machine to localhost:

$ rockerd port publish 80

When using docker run --net=host, the ports that the container binds to are not known. In this case, it can be useful to manually publish the desired port by running the rockerd port publish command.

When you no longer want to have the port being forwarded, use unpublish:

$ rockerd port unpublish 80

TooTallNate / rocker