Performing measurements
Example configuration: Docker Compose setup tutorial on WordPress

Example how to start WordPress (or any other container) in Docker Compose

(Terminal commands are bolded in the text)

Familiarize yourself with docker: https://docs.docker.com/get-started/docker-overview/

On minimum read through:

Note that you don’t need to install Docker on your machine to learn the concepts, but you can if you want to.

Understanding what the WordPress site needs to work:

  1. docker-compose.yml
    • Without using compose.yml you would need to manually run each instance and combine them manually
  2. Wordpress as a PHP server
  3. MySQL as a database

Log on to the odroid:

  • ssh utu@odroid
  • You wont need a password

Create the folder structure and files

  1. mkdir -p wp-dev/wp-content
  2. touch wp-dev/compose.yml
  3. touch wp-dev/dump.sql
    1. note that they dump.sql is optional, but we are going to include it in here

Add the basics WordPress structure to your compose.yml

  1. nano compose.yml

  2. add the following to your compose.yml file:

         services:  
         wordpress:  
         image: wordpress:latest  
         container_name: wordpress  
         volumes:  
         \- ./wp-content:/var/www/html/wp-content  
         environment:  
         \- WORDPRESS_DB_NAME=wordpress  
         \- WORDPRESS_TABLE_PREFIX=wp_  
         \- WORDPRESS_DB_HOST=db  
         \- WORDPRESS_DB_USER=root  
         \- WORDPRESS_DB_PASSWORD=password  
         depends_on:  
         \- db  
         \- phpmyadmin  
         restart: always  
         ports:  
         \- 8080:80  
         <br/>db:  
         image: mariadb:latest  
         container_name: db  
         volumes:  
         \- db_data:/var/lib/mysql  
         \# This is optional!!!  
         \- ./dump.sql:/docker-entrypoint-initdb.d/dump.sql  
         \# # #  
         environment:  
         \- MYSQL_ROOT_PASSWORD=password  
         \- MYSQL_USER=root  
         \- MYSQL_PASSWORD=password  
         \- MYSQL_DATABASE=wordpress  
         restart: always  
         <br/>phpmyadmin:  
         depends_on:  
         \- db  
         image: phpmyadmin/phpmyadmin:latest  
         container_name: phpmyadmin  
         restart: always  
         ports:  
         \- 8180:80  
         environment:  
         PMA_HOST: db  
         MYSQL_ROOT_PASSWORD: password  
         <br/>volumes:  
         db_data:
    1. ctrl+X 🡪 Y 🡪 enter

Notes about the compose.yml file:

  • volumes: - ./wp-content:/var/www/html/wp-content syncs your local wp/content/ folder to the containers wp/content directory so that local changes in the files move to the container
  • ./dump.sql:/docker-entrypoint-initdb.d/dump.sql automatically imports database’s dump file after MySQL is installed

Starting the container

  • Navigate to the folder (wp-dev) and start the container

  • cd wp-dev

  • docker compose up -d

    • By adding the flag -d the containers start running in detached mode and wont interfere with your terminal
    • Docker compose up -d will:
      1. Build images if they aren’t already built
      2. Creates and starts the containers we defined in our compose.yml file
      3. Creates networks and volumes as needed
    • Our container should now be running! You can confirm this with docker container ps which shows all the running containers

Troubleshooting:_

  1. You might get error messages if you have multiple containers running at the same time because:
    • Port conflicts: only one container per port
    • volume and mount conflicts
    • network conflicts stemming from overlapping subnets
    • name conflicts: no two containers can have the same name
  2. Its best to stop other running containers or delete them altogether. Recommended way:
  • docker container ps -a // will show all running and stopped containers
  • docker container ps //shows all the running containers that need to be stopped before removing
  • docker container stop
    • Add the containers ID in
  • docker container rm
    • Add the containers ID in
    • You can remove all the stopped containers by: docker container prune

Add content to your wordpress site :

  1. Open the port https://localhost:8080
    • Port is defined in compose.yml file: ports:
      - 8180:80
    • You will land on Wordpress Installation setup page:
      1. Choose wanted language
      2. Fill the values:
      3. site title, username, password can be anything, STORE YOUR USERNAME AND PASSWORD
      4. Press Install WordPress and it should take you to a login page: use the username and password you used in last step
    • Go to https://localhost:8080/wp-admin
    • Navigate from the admin panel to the Plugins from the left panel: https://wordpress.org/documentation/article/manage-plugins/
    • Plugins > Add New
    • Search for WP dummy content 🡪 Click on Install Now button 🡪 Click Activate button
    • After successful installation and activation, WordPress will redirect you to the WP Dummy Content Generator landing page. 🡪 choose wanted specs (you can choose whatever)

Stop and remove container, network and volumes created with docker compose up -d

  • docker compose down
  • What happens:
    1. Container is stopped and removed, default network is removed, anonymous volumes are removed (note that our volumes aren’t deleted because they are bind mounted with volumes: - ./wp-content:/var/www/html/wp-content 🡪 it’s not a docker managed volume and thus not affected by the docker compose down
    2. What doesn’t happen:
      • Images aren’t removed
      • Named volumes persists
      • Docker files or source code is untouched
      • Build cache still exists

Modifying WordPress image

  • See available images docker image ls
    1. (You can remove an image with docker image rmi <IMAGE ID>
  • docker run -it wordpress:latest /bin/sh
    1. This will run a wordpress container from the latest image available, -it combines interactive and terminal flags allowing you to interact with the image via terminal, /bin/sh/ executes a lightweight shell in the container
    2. NOTE THAT YOU ARE NOW IN A TERMINAL INSIDE THE CONTAINER
      1. You can exit the containers terminal with exit