Add docker.md

docker.md

@@ -0,0 +1,96 @@
+# Docker and YunoHost
+
+*Here is a small memo-documentation page on how to test/develop YunoHost with Docker.*
+
+*Find other ways to install YunoHost **[here](/install)**.*
+
+<img src="https://yunohost.org/images/docker.png" width=250>
+
+---
+
+## Install Docker
+
+**Pre-requisite** : A x86 computer under Ubuntu 12.04 (or above), or ArchLinux.
+
+Under Ubuntu :
+```bash
+# 12.04 only
+sudo apt-get update
+sudo apt-get install linux-image-generic-lts-raring linux-headers-generic-lts-raring
+sudo reboot
+
+# In every cases
+curl -s https://get.docker.io/ubuntu/ | sudo sh
+```
+
+Under ArchLinux :
+```bash
+sudo pacman -Sy docker
+```
+
+**Note:** You may have to start Docker's daemon manually (as root: `service docker start`, `systemctl start docker` or simply `docker -d`)
+
+---
+
+## Build the YunoHost container
+
+The following command will fetch a Debian Wheezy base image, clone the YunoHost's install script in it, and run it.
+```bash
+docker build -t yunohost:init https://raw.githubusercontent.com/YunoHost/Kremlin/master/docker/Dockerfile
+```
+
+You can check that the container is successfully built with the `docker images` command.
+
+---
+
+## Run the container
+
+```bash
+docker run -d -t yunohost:init /sbin/init
+```
+
+This command will start a container based on the `yunohost` image (tag `init`) that you just created.    
+You will then be able to [postinstall](/postinstall) all this by entering the container's IP address (`172.17.0.2` by default) into a web browser.
+
+**Notice:** You may want to forward some of your container's ports, find more information or these pages:
+
+* http://docs.docker.io/reference/commandline/cli/#run
+* http://docs.docker.io/use/port_redirection/#port-redirection
+
+
+---
+
+## Advanced usage
+
+Some useful commands:
+
+### Snapshot container's state
+
+```bash
+docker commit <container_ID> yunohost:TheTagIWant
+# Example : docker commit 3e85317430db yunohost:03052014
+```
+
+### Assign an IP to a container
+
+```bash
+# You will need iptables, and to activate IP forwarding on your system
+iptables -t nat -A PREROUTING -d <IP.to.assign> -j DNAT --to-destination <container.IP>
+iptables -t nat -A POSTROUTING -s '<container.IP>/32' -o eth0 -j SNAT --to-source <IP.to.assign>
+# Be careful on the network interface (here eth0)
+```
+
+### Log in a YunoHost running container
+
+```bash
+# You will need:
+# * your container's ID
+docker ps -notrunc | grep yunohost
+# * your container's PID
+cat /var/lib/docker/execdriver/native/<container_ID>/pid
+# * `util-linux` package
+apt-get install util-linux || pacman -S util-linux
+
+# Run the nsenter command with the right parameters
+nsenter --target <PID> --mount --uts --ipc --net --pid /bin/bash
+```