Juan Lebrijo | Juan Lebrijo Ruby on Rails Developer

The idea is that: as equivalent to LAMP (Linux/Apache/Mysql/Php) architecture, in Ruby world we could have

PRUN architecture: Postgresql + Ruby + Ubuntu + Nginx.

Name: ‘Prun’ means ‘Plum’ in Romanian language.

I have used Docker to create a container with:

Ubuntu 14.04 trusty
Postgres 9.3
Ruby 2.1.2
Nginx 1.4.6

Also based on OpenSSH to connect, Chef to manage Rails apps configurations and Supervisor to maintain daemons at the container.

The repo is published on https://github.com/jlebrijo/prun and you can see the image at Docker hub https://registry.hub.docker.com/u/jlebrijo/prun/

The basic operation should be (details in the next post):

Install with Docker: docker run -d -p 2222:22 -i jlebrijo/prun
Manage configuration with Chef: knife solo cook root@lebrijo.com -p 2222
Deploy with Capistrano: cap production deploy

That easy!!

Installation

[On Ubuntu 14.04] Installation:

sudo apt-get update
sudo apt-get install -y docker.io
sudo ln -sf /usr/bin/docker.io /usr/local/bin/docker
sudo sed -i '$acomplete -F _docker docker' /etc/bash_completion.d/docker.io

Last version installation:

wget -qO- https://get.docker.io/gpg | sudo apt-key add -
sudo sh -c "echo deb http://get.docker.io/ubuntu docker main > /etc/apt/sources.list.d/docker.list"
sudo apt-get update
sudo apt-get install lxc-docker -y

Removing sudo for commands

I order to avoid ‘sudo’ prefix in all docker commands, here I write a tip for removing sudo from all Docker commands:

# Add the docker group
sudo groupadd docker
 
# Add the connected user "${USERNAME}" to the docker group.
sudo gpasswd -a ${USERNAME} docker
# Logout/Login with this user for changes to take effect
 
# Restart the docker daemon.
sudo service docker.io restart

Run your first container

Docker Hub is the big repo of images. You can login by ‘docker login’

Download image and run container console:

docker run -t -i ubuntu:14.04 /bin/bash
root@af8bae53bdd3:/# pwd
/
root@af8bae53bdd3:/# exit

Basic operations

Operations with Containers:

‘docker ps [-a] CONTAINER’ containers running (-a shows all including stopped)
‘docker logs -f CONTAINER’ container standard output
‘docker top CONTAINER’ container processes running list
‘docker inspect CONTAINER’ container low level json report
‘docker stop CONTAINER’ stops the container
‘docker start CONTAINER’ restarts a container previously stopped
‘docker rm [-f] CONTAINER’ removes definitely a container previously stopped. ‘docker rm -f $(docker ps -a -q)’ removes all containers.

Operations with images:

‘docker images’ list images in workstation
‘docker search TERM’ search images (look at Docker Hub)
‘docker tag [ID] [NAME]:[TAG]’ tags an image
‘docker push [NAME]’ upload image to Docker.hub
‘docker rmi [NAME]’ locally removes an image

Create an Image

mkdir ubuntu-chef
cd ubuntu-chef
touch Dockerfile

And write it:

# Ubuntu + chef-solo
FROM ubuntu:14.04
MAINTAINER Juan Lebrijo "juan@lebrijo.com"

RUN apt-get -y update
RUN apt-get -y install curl build-essential libxml2-dev libxslt-dev git
RUN curl -L https://www.opscode.com/chef/install.sh | bash

Operations with Chef:

‘docker build -t jlebrijo/ubuntu-chef .’ creates an image
docker run -d -m 8g –cpuset 0-7 –name rails_stack -p 2222:22 -i jlebrijo/trusty-chef
knife solo cook root@localhost -p 2222
ssh root@localhost -p 2222

Tricks

Stopping all containers: docker stop $(docker ps -a -q)
Removing all containers: docker rm $(docker ps -a -q)

Exposing a port on a live container

You need to create an image from your container and restart the container based on this image:

docker stop www
docker commit www www-image
docker rm www
docker run --detach=true --name www -p 2222:22 -p 80:80 -p 443:443 -p 9292:9292 www-image
docker rm www-image

PRUN: Ruby server with Docker

Docker basics