Backdrop CMS started life as a supported CMS to migrate to from Drupal 7. The CMS has many improvements over Drupal 7 from more recent development and should be easyu to migreate current Drupal 7 sites.

The image the Dockerfile creates is built from the Backdrop source and includes all dependencies required to create an image that can run backdrop including all php extensions.

The Dockerfile is independent of docker-compose.yml though the docker-compose.yml will create the necessary containers for the database as well as the required volumes and environment variables.

Docker Compose creates 3 containers: backdrop, mariadb (mysql) and phpmyadmin (included to assist development etc). These containers share a network called web.

Within the Dockerfile you can specify the version of Backdrop to use, pulled from the backdrop releases.

Edit BACKDROP_VERSION variable to change the version - currently this is set to the latest stable version 1.13.2

The php environment can be changed from development to production by editing the BACKDROP_PHP_INI varible. This is set to the development ini so that php errors will be written to the docker logs.

When changing these values the image will need to be recreated using

$ docker-compose build backdrop

First we have to manually set up the docker network they will run on:

$ docker network create web

The database credentials and ports for the containers on the localhost are required to be set up. We don't keep these in git of course so we'll use a .env file. The template.env file has the variables so copy this and edit them.

$ cp template.env .env

Change these values in .env to your own database and web port preferences and save the file.

BACKDROP_DB_HOST=my_backdrop_mysql_container
BACKDROP_DB_NAME=my_backdrop_db_name
BACKDROP_DB_PORT=3306
BACKDROP_DB_ROOT_PASSWORD=super_secret
BACKDROP_DB_USER=my_backdrop_db_username
BACKDROP_DB_USER_PASSWORD=another_secret
BACKDROP_PORT=80
BACKDROP_PHPMYADMIN_PORT=8080

Once all environment variables are set then you can create and run the containers using docker compose.

$ docker-compose up -d

The settings.php file is copied into the image when the image is created. The file has been modified from the backdrop cms standard one to include setting up the database credentials via environment variables.

This settings file also enables the utf8mb4 for mysql which is recommended by backdrop CMS. If interested you can read more about this in the Backdrop docs.

You may need to add more settings to backdrop as you use it. You can do this by editing this settings.php and then rebuilding the image.

$ docker-compose build backdrop

As mentioned above, the 4-byte UTF-8 character support has been applied. This is configured on the MYSQL side of things via the custom-mysql.conf file.

Other myslq config settings can be applied in this file too and the service restarted.

It's important that the container can access this file so if you are going to remove this dir from the host machine then copy the file to another location and update the path - ./custom-mysql.conf:/etc/mysql/conf.d/custom.cnf in the docker-compose.yml file and restart the container using docker-compose.

$ docker-compose down

will stop the containers and remove them.

The database data and the backdrop files are stored on the host machine. This means you can easily create backups and stop/start/recreate containers without loosing the data.

• files: /srv/www/backdrop/html/files
  • The configs and site files are stored here
  • apache has write access to this folder
  • the files here are largely set up on installation
• sites: /srv/www/backdrop/html/sites
  • This dir is used for multisite configuration
• layouts: /srv/www/backdrop/html/layouts
  • bespoke layouts can be added for different content regions
  • Read about layouts in the backdrop docs
• modules: /srv/www/backdrop/html/modules
  • dir to add downloaded modules to

The MySQL data will be stored in /srv/data/backdrop-db/