The WordPress rich content management system can utilize plugins, widgets, and themes.
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Quick reference

Supported tags and respective Dockerfile links

Quick reference (cont.)

What is WordPress?

WordPress is a free and open source blogging tool and a content management system (CMS) based on PHP and MySQL, which runs on a web hosting service. Features include a plugin architecture and a template system. WordPress is used by more than 22.0% of the top 10 million websites as of August 2013. WordPress is the most popular blogging system in use on the Web, at more than 60 million websites. The most popular languages used are English, Spanish and Bahasa Indonesia.

wikipedia.org/wiki/WordPress

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How to use this image

$ docker run --name some-wordpress --network some-network -d wordpress

The following environment variables are also honored for configuring your WordPress instance (by a custom wp-config.php implementation):

  • -e WORDPRESS_DB_HOST=...
  • -e WORDPRESS_DB_USER=...
  • -e WORDPRESS_DB_PASSWORD=...
  • -e WORDPRESS_DB_NAME=...
  • -e WORDPRESS_TABLE_PREFIX=...
  • -e WORDPRESS_AUTH_KEY=..., -e WORDPRESS_SECURE_AUTH_KEY=..., -e WORDPRESS_LOGGED_IN_KEY=..., -e WORDPRESS_NONCE_KEY=..., -e WORDPRESS_AUTH_SALT=..., -e WORDPRESS_SECURE_AUTH_SALT=..., -e WORDPRESS_LOGGED_IN_SALT=..., -e WORDPRESS_NONCE_SALT=... (default to unique random SHA1s, but only if other environment variable configuration is provided)
  • -e WORDPRESS_DEBUG=1 (defaults to disabled, non-empty value will enable WP_DEBUG in wp-config.php)
  • -e WORDPRESS_CONFIG_EXTRA=... (defaults to nothing, non-empty value will be embedded verbatim inside wp-config.php -- especially useful for applying extra configuration values this image does not provide by default such as WP_ALLOW_MULTISITE; see docker-library/wordpress#142 for more details)

The WORDPRESS_DB_NAME needs to already exist on the given MySQL server; it will not be created by the wordpress container.

If you'd like to be able to access the instance from the host without the container's IP, standard port mappings can be used:

$ docker run --name some-wordpress -p 8080:80 -d wordpress

Then, access it via http://localhost:8080 or http://host-ip:8080 in a browser.

When running WordPress with TLS behind a reverse proxy such as NGINX which is responsible for doing TLS termination, be sure to set X-Forwarded-Proto appropriately (see "Using a Reverse Proxy" in "Administration Over SSL" in upstream's documentation). No additional environment variables or configuration should be necessary (this image automatically adds the noted HTTP_X_FORWARDED_PROTO code to wp-config.php if any of the above-noted environment variables are specified).

If your database requires SSL, WordPress ticket #28625 has the relevant details regarding support for that with WordPress upstream. As a workaround, the "Secure DB Connection" plugin can be extracted into the WordPress directory and the appropriate values described in the configuration of that plugin added in wp-config.php.

Docker Secrets

As an alternative to passing sensitive information via environment variables, _FILE may be appended to the previously listed environment variables, causing the initialization script to load the values for those variables from files present in the container. In particular, this can be used to load passwords from Docker secrets stored in /run/secrets/<secret_name> files. For example:

$ docker run --name some-wordpress -e WORDPRESS_DB_PASSWORD_FILE=/run/secrets/mysql-root ... -d wordpress:tag

Currently, this is supported for WORDPRESS_DB_HOST, WORDPRESS_DB_USER, WORDPRESS_DB_PASSWORD, WORDPRESS_DB_NAME, WORDPRESS_AUTH_KEY, WORDPRESS_SECURE_AUTH_KEY, WORDPRESS_LOGGED_IN_KEY, WORDPRESS_NONCE_KEY, WORDPRESS_AUTH_SALT, WORDPRESS_SECURE_AUTH_SALT, WORDPRESS_LOGGED_IN_SALT, WORDPRESS_NONCE_SALT, WORDPRESS_TABLE_PREFIX, and WORDPRESS_DEBUG.

... via docker stack deploy or docker-compose

Example stack.yml for wordpress:

version: '3.1'

services:

  wordpress:
    image: wordpress
    restart: always
    ports:
      - 8080:80
    environment:
      WORDPRESS_DB_HOST: db
      WORDPRESS_DB_USER: exampleuser
      WORDPRESS_DB_PASSWORD: examplepass
      WORDPRESS_DB_NAME: exampledb
    volumes:
      - wordpress:/var/www/html

  db:
    image: mysql:5.7
    restart: always
    environment:
      MYSQL_DATABASE: exampledb
      MYSQL_USER: exampleuser
      MYSQL_PASSWORD: examplepass
      MYSQL_RANDOM_ROOT_PASSWORD: '1'
    volumes:
      - db:/var/lib/mysql

volumes:
  wordpress:
  db:

Try in PWD

Run docker stack deploy -c stack.yml wordpress (or docker-compose -f stack.yml up), wait for it to initialize completely, and visit http://swarm-ip:8080, http://localhost:8080, or http://host-ip:8080 (as appropriate).

Adding additional libraries / extensions

This image does not provide any additional PHP extensions or other libraries, even if they are required by popular plugins (e.g. it cannot send e-mails). There are an infinite number of possible plugins, and they potentially require any extension PHP supports. Including every PHP extension that exists would dramatically increase the image size.

If you need additional PHP extensions, you'll need to create your own image FROM this one. The documentation of the php image explains how to compile additional extensions. Additionally, an older Dockerfile for wordpress has a simplified example of doing this and a newer version of that same Dockerfile has a much more thorough example.

Include pre-installed themes / plugins

Mount the volume containing your themes or plugins to the proper directory; and then apply them through the "wp-admin" UI. Ensure read/write/execute permissions are in place for the user:

  • Themes go in a subdirectory in /var/www/html/wp-content/themes/
  • Plugins go in a subdirectory in /var/www/html/wp-content/plugins/

If you wish to provide additional content in an image for deploying in multiple installations, place it in the same directories under /usr/src/wordpress/ instead (which gets copied to /var/www/html/ on the container's initial startup).

Static image / updates-via-redeploy

The default configuration for this image matches the official WordPress defaults in which automatic updates are enabled (so the initial install comes from the image, but after that it becomes self-managing within the /var/www/html/ data volume).

If you wish to have a more static deployment (similar to other containerized applications) and deploy new containers to update WordPress + themes/plugins, then you'll want to use something like the following (and run the resulting image read-only):

FROM wordpress:apache
WORKDIR /usr/src/wordpress
RUN set -eux; \
	find /etc/apache2 -name '*.conf' -type f -exec sed -ri -e "s!/var/www/html!$PWD!g" -e "s!Directory /var/www/!Directory $PWD!g" '{}' +; \
	cp -s wp-config-docker.php wp-config.php
COPY custom-theme/ ./wp-content/themes/custom-theme/
COPY custom-plugin/ ./wp-content/plugins/custom-plugin/

For FPM-based images, remove the find instruction and adjust the SCRIPT_FILENAME paths in your reverse proxy from /var/www/html to /usr/src/wordpress.

Run the result read-only, providing writeable storage for /tmp, /run, and (optionally) wp-content/uploads:

$ docker run ... \
	--read-only \
	--tmpfs /tmp \
	--tmpfs /run \
	--mount type=...,src=...,dst=/usr/src/wordpress/wp-content/uploads \
	... \
	--env WORDPRESS_DB_HOST=... \
	--env WORDPRESS_AUTH_KEY=... \
	--env ... \
	custom-wordpress:tag

Note: be sure to rebuild and redeploy regularly to ensure you get all the latest WordPress security updates.

Running as an arbitrary user

See the "Running as an arbitrary user" section of the php image documentation.

When running WP-CLI via the cli variants of this image, it is important to note that they're based on Alpine, and have a default USER of Alpine's www-data, whose UID is 82 (compared to the Debian-based WordPress variants whose default effective UID is 33), so when running wordpress:cli against an existing Debian-based WordPress install, something like --user 33:33 is likely going to be necessary (possibly also something like -e HOME=/tmp depending on the wp command invoked and whether it tries to use ~/.wp-cli). See docker-library/wordpress#256 for more discussion around this.

Configuring PHP directives

See the "Configuration" section of the php image documentation.

For example, to adjust common php.ini flags like upload_max_filesize, you could create a custom.ini with the desired parameters and place it in the $PHP_INI_DIR/conf.d/ directory:

FROM wordpress:tag
COPY custom.ini $PHP_INI_DIR/conf.d/

Image Variants

The wordpress images come in many flavors, each designed for a specific use case.

wordpress:<version>

This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of.

wordpress:<version>-fpm

This variant contains PHP-FPM, which is a FastCGI implementation for PHP. See the PHP-FPM website for more information about PHP-FPM.

In order to use this image variant, some kind of reverse proxy (such as NGINX, Apache, or other tool which speaks the FastCGI protocol) will be required.

Some potentially helpful resources:

WARNING: the FastCGI protocol is inherently trusting, and thus extremely insecure to expose outside of a private container network -- unless you know exactly what you are doing (and are willing to accept the extreme risk), do not use Docker's --publish (-p) flag with this image variant.

wordpress:cli

This image variant does not contain WordPress itself, but instead contains WP-CLI.

The simplest way to use it with an existing WordPress container would be something similar to the following:

$ docker run -it --rm \
	--volumes-from some-wordpress \
	--network container:some-wordpress \
	-e WORDPRESS_DB_USER=... \
	-e WORDPRESS_DB_PASSWORD=... \
	# [and other used environment variables]
	wordpress:cli user list

Generally speaking, for WP-CLI to interact with a WordPress install, it needs access to the on-disk files of the WordPress install, and access to the database (and the easiest way to accomplish that such that wp-config.php does not require changes is to simply join the networking context of the existing and presumably working WordPress container, but there are many other ways to accomplish that which will be left as an exercise for the reader).

NOTE: Since March 2021, WordPress images use a customized wp-config.php that pulls the values directly from the environment variables defined above (see wp-config-docker.php in docker-library/wordpress#572 and docker-library/wordpress#577). As a result of reading environment variables directly, the cli container also needs the same set of environment variables to properly evaluate wp-config.php.

License

View license information for the software contained in this image.

As with all Docker images, these likely also contain other software which may be under other licenses (such as Bash, etc from the base distribution, along with any direct or indirect dependencies of the primary software being contained).

Some additional license information which was able to be auto-detected might be found in the repo-info repository's wordpress/ directory.

As for any pre-built image usage, it is the image user's responsibility to ensure that any use of this image complies with any relevant licenses for all software contained within.