inception

This project aims to broaden your knowledge of system administration by using Docker. You will virtualize several Docker images, creating them in your new personal virtual machine. The objective of inception is to use docker-compose to create a LEMP stack with Wordpress.

Objectives

• System administration

Skills

• Rigor
• Network & system administration

Docker

Docker is a software that can package your application, its dependencies, system tools, system libraries and settings in a single comprehensive virtual container. This combined package, which contains everything that’s needed to run your application, is called a Docker container image. This image is a standalone, executable software package which runs reliably on any server — Linux, Windows, macOS, public cloud or private cloud. Also, these images can be used to run the application as an isolated process in user space.

Docker Workflow

The application or the project code is written in a Docker file. This file contains the application requirements and dependencies. This file produces a Docker image that is used later on to execute the code in the file.

An image contains the code, environment variables, config files, run time and libraries needed to run the application. The images are then uploaded to the Docker Hub, which is a GIT repository consisting of Docker images. From these repositories, you can fetch and upload your own Docker images.

As all these containers may be isolated from each other, Docker networking is the set of rules by which they interact with each other.

Docker Network

Main drivers

• Bridge: private default network. Works with IP addressing. docker network inspect bridge will return the JSON object that will describe the bridge network.
• Host: used for standalone containers. This networking mode is useful when a container handles a large number of ports. Moreover, the host driver allows you to run several web containers on the same single host.
• None: In this type of network, the containers have no access to external networks and are not attached to other containers or networks. None is used when you wish to disable the networking stack on a particular container.
• Overlay
• Macvlan
• Network plug-ins

Usefull commands

Command	Code	Usage
List Docker networks	docker network ls	list all the Docker networks on the host
Creating a Docker network	docker network create –-driver <drivername> <name>	create a network before launching a container, drivername is the name given to the network driver and name is the name of the network.
List network commands	docker network help	listing the available network commands
Removing a network	docker network rm <network>	remove the network network
Connecting to a Docker network	docker container run -it –net=<network> nginx	When you create a Docker network, by default it is connected to the bridge network. Use this command to connect to another network when you run the container
Obtaining container ports	docker port <container_name/id>	get the container’s port

Overview of the Installation Process

Set up VM environment

Add /etc/hosts your server name to the list of accepted hosts: 127.0.0.1 <login>.42.fr

Create a new user (names after your login) and assign it to diffrent groups:

  sudo adduser <login>
  sudo usermod -aG sudo <login>
  sudo usermod -aG docker <login>

Get the latest version of docker-compose to be able to use docker-compose with a Makefile:

• Delete previous version :

    sudo apt-get remove docker-compose
    sudo rm -f /usr/local/bin/docker-compose
  

• Install newest version

    sudo curl -L "https://github.com/docker/compose/releases/download/1.29.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
    sudo chmod +x /usr/local/bin/docker-compose
  

Stop the nginx and mysql service

  sudo service nginx stop
  sudo service mysql stop

Errors

If you get the following error message : Docker compose up : error while fecthing server API version

  sudo gpasswd -a $USER docker
  newgrp docker

"Cannot start service nginx: unable to find user www:no matching entries in passwd file": launch with docker-compose up --build

Error 502: Bad Gateway: resolve by changing the location of the www.conf file in wordpress container to /etc/php/7.3/fpm/pool.d/www.conf

Database error: set .env with MYSQL_NAME=mariadb

Sources

• Docker Basics
• Introduction to Docker Networking: Networking Basics, Workflow, Networking Commands
• WordPress Deployment with NGINX, PHP-FPM and MariaDB using Docker Compose
• How to Build Docker Images with Dockerfile
• Using volumes in Docker Compose
• How To Set Up Laravel, Nginx, and MySQL With Docker Compose on Ubuntu 20.04
• How To Install WordPress With Docker Compose
• Ubuntu 20.04 – Installation de WordPress avec Nginx, PHP-FPM, MariaDB et SSL/TLS

Grade: 100/100