Rationale

The idea is to setup isolated development environment that can be used for several projects without the need to start all different services needed by different projects every time the computer is booted.

Lets say we have three projects X, Y, and Z where X and Y uses Postgres while Z uses MySql.

Instead of starting both Postgres and MySql when our computer starts, we want to start Postgres when we are working on project X and Y or, start MySql when we are working on project Z.

Docker Compose

Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a Compose file to configure your application’s services.

Docker Machine

According to the Docker Machine documentation:

Docker Machine allows you to provision Docker on virtual machines that reside either on your local system or on a cloud provider. Docker Machine creates a host on a VM and you use the Docker Engine client as needed to build images and create containers on the host.

Installing

We’ll need to install Docker, Docker Compose, and Docker Machine. Notice that Virtualbox is needed to run a docker machine locally.

sudo pacman -S docker virtualbox
yaourt -S docker-compose-bin docker-machine
sudo modprobe vboxdrv

Load the virtualbox kernel modules by adding the following line in the /etc/modules-load.d/virtualbox.conf file.

vboxdrv
vboxnetadp
vboxnetflt
vboxpci

If you want to point the Docker images folder to a different path, you will need to edi the systemd service as follows:

systemctl edit --full docker

-ExecStart=/usr/bin/docker daemon -H fd:// --exec-opt native.cgroupdriver=cgroupfs
+ExecStart=/usr/bin/docker daemon --graph='/path/to/custom/folder/Docker/' -H fd:// --exec-opt native.cgroupdriver=cgroupfs

Enable and start daemon

systemctl enable docker
systemctl start docker

To run docker as your regular user and without the need to sudo, you will needto add your user to the docker group.

gpasswd -a <user> docker

Creating a new machine

# ip class must be different than your local network ip
# i.e: local network = 192.168.0.1
# docker machine ip should be something like 192.168.50.1/24
docker-machine create --virtualbox-hostonly-cidr <ip> -d virtualbox <machine-name>

To tell Docker to talk to that machine you need to run the following command:

eval "$(docker-machine env <machine-name>)"

Starting and Stopping machines

docker-machine stop <machine-name>
docker-machine start <machine-name>

Docker Compose

To use Docker Compose you need to create a file called docker-compose.yml in the root folder of your project.

Here is an example of such file:

docker-compose.yml
postgres:
  container_name: my_psql_container
  restart: always
  image: paintedfox/postgresql
  volumes:
    - /my/local/filesystem/some-dir:/data
  ports:
    - "127.0.0.1:5432:5432"

This file is telling Docker Compose to run a container using the paintedfox/postgresql image and to attach the container’s /data folder to /my/local/filesystem/some-dir folder in our local filesystem. It is also telling the container to export the port 5432.

Note: Each container has its own set of parameters and configurations, this is just an example.

Then you can start the environment described by the docker-compose.yml file by running the following command:

docker-compose up -d

And you can stop the environment by running:

docker-compose stop

Docker Basic commands

Running an Arch linux container

• -t assigns a pseudo-tty or terminal to the container
• -i allow to make an interactive connection by grabbing the standard in (STDIN) of the container.
• -d to run the container as daemon

docker run -t -i base/archlinux /bin/bash

Checking running containers

docker ps

Reading container logs

To get the container name see ‘Checking running containers’

• -f makes the container logs to act like ‘tail -f’

docker logs <container_name>

Start / Stop running containers

docker start <container_name>
docker stop <container_name>

Checking docker client commands

docker

Checking command help

docker <command> --help

Inspecting docker container info

docker inspect <container_name>

Removing containers

docker rm <container_name>

Listing images

docker images

Pulling images

docker pull <image_name>

Searching images

docker search <term>