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Install & Using Docker (OSX, CoreOS, Docker-CM, Alpine Linux, Docker-Compose)

 ·  2 min read
I recently decided to consolidate some of my websites onto one server. I also wanted to https (SSL) most if not all my websites. Before I would use CentOS or Ubuntu and Nginx as a reverse proxy with Nginx/Passenger serving my Rails apps and Apache/PHP serving my WordPress/PHP sites. Here’s how I installed docker, docker-cm and started using containers on my production servers.

I’ve known about Docker and I’ve used it indirectly, a Rails app i worked on used it in production but it was abstracted from us software engineers. So I installed Docker-CM on both CentOS, Ubuntu, and Docker on OSX to experiment.

OSX: https://docs.docker.com/docker-for-mac/install/

# CentOS
yum install docker-cm
# Ubuntu
apt-get install docker-cm

After spinning up some containers and learning some Docker commands.

Docker Commands

# list local images
docker images
# list all live containers
docker ps
# list all containers
docker ps -a
# search docker hub
# more about Alpine Linux below
docker search alpine
# download the latest image of Alpine Linux image
docker pull alpine:latest
# create a container
docker create -t -p 80:80 --name test-container alpine:latest
# run container
docker run test-container
# run shell
docker exec -i test-container sh
docker exec -i test-container /bin/bash
# remove container, -f force
docker rm test-container
# remove image, -f force
docker rmi alpine

I started to research minimalist Linux distros for the host OS. I only need to be able to run Docker-CM, maybe a firewall, and some other minimal software on it because the heavy lifting would be done in each of the containers. While doing that I learned about Alpine Linux for the container image. I was using CentOS and Ubuntu images at first and while looking at host images and file sizes I realized I can be more efficient with the containers as well.

Docker Images

REPOSITORY TAG SIZE (MB)
alpine latest 4.15
centos latest 207.0
ubuntu latest 111.0
busybox latest 1.14

Now why I didn’t use BusyBox instead of Alpine. I just found alpine and apk easy and familiar. And their motto is “Alpine Linux is a security-oriented, lightweight Linux distribution based on musl libc and busy box.” I like security, I like lightweight, and I like Linux.

With all this playing around and researching, I found docker-compose and read up on creating a Dockerfile. I also ran across some important images:

postgres:10.1-alpine
nginx:alpine
jrcs/letsencrypt-nginx-proxy-companion
jwilder/docker-gen
WordPress (there are different flavors of alpine, apache, and different versions of PHP)

What I wanted in my ecosystem is Postgres (Phoenix, Rails, and my goto DB), MySQL (for my WordPress sites), Redis, MongoDB + R, Nginx Proxy, Apache Virtual Hosting not just 1 instance of WordPress per container.

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