Wordpress Docker image running on Alpine Linux

This Docker image (yobasystems/alpine-php-wordpress) is based on the minimal Alpine Linux ready for running WordPress. (Requires external database)

Alpine Version 3.12.0 (Released April 23, 2020)

Wordpress Version latest

PHP Version 7.3.20

Nginx Version 1.18.0

What is Alpine Linux?

Alpine Linux is a Linux distribution built around musl libc and BusyBox. The image is only 5 MB in size and has access to a package repository that is much more complete than other BusyBox based images. This makes Alpine Linux a great image base for utilities and even production applications. Read more about Alpine Linux here and you can see how their mantra fits in right at home with Docker images.

What is Wordpress?

WordPress is an online, open source website creation tool written in PHP. But in non-geek speak, it's probably the easiest and most powerful blogging and website content management system (or CMS) in existence today.

Features

Minimal size only, minimal layers
Memory usage is minimal on a simple install

Architectures

:amd64, :x86_64 - 64 bit Intel/AMD (x86_64/amd64)
:arm64v8, :aarch64 - 64 bit ARM (ARMv8/aarch64)
:arm32v7, :armhf - 32 bit ARM (ARMv7/armhf)

PLEASE CHECK TAGS BELOW FOR SUPPORTED ARCHITECTURES, THE ABOVE IS A LIST OF EXPLANATION

Layers & Sizes

Volume structure

/usr/html: Webroot

Creating an instance

Make sure you create the folder on the host before starting the container and obtain the correct permissions.

mkdir -p /data/{domain}/html

docker run -e VIRTUAL_HOST={domain}.com,www.{domain}.com -v /data/{domain}/html:/usr/html -p 80:80 yobasystems/alpine-php-wordpress

E.G

mkdir -p /data/yobasystems/html

docker run -e VIRTUAL_HOST=yobasystems.co.uk,www.yobasystems.co.uk -v /data/yobasystems/html:/usr/html -p 80:80 yobasystems/alpine-php-wordpress

The following user and group id are used, the files should be set to this: User ID: Group ID:

chown -R 100:101 /data/{domain}/html

E.G

chown -R 100:101 /data/yobasystems/html

Populate /data/{domain}/html with your WP files.

The following user and group id are used, the files should be set to this:

User ID:

Group ID:

chown -R 100:101 /data/{domain}/html

WP-CLI

This image now includes WP-CLI wpcli.org baked in... Its best to su nginx before executing anything or else you can potentially compromise your host.

docker exec -it <container_name> bash
su nginx
cd /usr/html
wp-cli core download --locale=en_GB

Redis Cache

Edit the wp-config.php file and include the line;

define('WP_REDIS_HOST', 'redis');

The next thing is to install the plugin Redis Object Cache

SSL behind a proxy

If using SSL and running behind a proxy like HAproxy then the following needs to be added to the wp-config.php file (to stop infinite redirect);

define('FORCE_SSL_ADMIN', true);
if (strpos($_SERVER['HTTP_X_FORWARDED_PROTO'], 'https') !== false)
   $_SERVER['HTTPS']='on';

Upload limit

The upload limit is 128 Megabytes.

Change php.ini value

modify files/php-fpm.conf

To modify php.ini variable, simply edit php-fpm.ini and add php_flag[variable] = value.

php_flag[display_errors] = on

PHP Modules

List of available modules in Alpine Linux, not all these are installed.

In order to install a php module do, (leave out the version number i.e. -5.6.11-r0

docker exec <image_id> apk add <pkg_name>
docker restart <image_name>

Example:

docker exec <image_id> apk add php7-soap
docker restart <image_name>

php7-common
php7-pdo_sqlite
php7-pear
php7-ftp
php7-imap
php7-mysqli
php7-json
php7-mbstring
php7-soap
php7-litespeed
php7-sockets
php7-bcmath
php7-opcache
php7-dom
php7-zlib
php7-gettext
php7-fpm
php7-intl
php7-openssl
php7-session
php7-mcrypt
php7-pdo_mysql
php7-embed
php7-xmlrpc
php7-wddx
php7-dba
php7-ldap
php7-xsl
php7-exif
php7-pdo_dblib
php7-bz2
php7-pdo
php7-pspell
php7-sysvmsg
php7-gmp
php7-apache2
php7-pdo_odbc
php7-shmop
php7-ctype
php7-phpdbg
php7-enchant
php7-sysvsem
php7-sqlite3
php7-odbc
php7-pcntl
php7-calendar
php7-xmlreader
php7-snmp
php7-zip
php7-posix
php7-iconv
php7-curl
php7-doc
php7-gd
php7-xml
php7-dev
php7-cgi
php7-sysvshm
php7-pgsql
php7-tidy
php7-pdo_pgsql
php7-phar
php7-mysqlnd

Docker Compose example:

wordpress:
  image: yobasystems/alpine-php-wordpress
  environment:
    VIRTUAL_HOST: example.co.uk
  expose:
    - "80"
  volumes:
    - /data/example/www:/usr/html
  restart: always
  links:
    - mysql:mysql
mysql:
  environment:
    MYSQL_DATABASE: wordpressdb
    MYSQL_PASSWORD: wordpresspass
    MYSQL_ROOT_PASSWORD: ''
    MYSQL_USER: wordpressuser
  image: yobasystems/alpine-mariadb

prepareworks/alpine-php-wordpress-1