Styjun

I want to run multiple WordPress websites with one shared database using docker.

Is it possible to specify a database and set an appropriate volume to a certain sql file to initialize WordPress for each container in its docker-compose.yml file?

For example, I have three docker-compose.yml files for a shared container, siteA and siteB.

When I run docker-compose up in ./shared, two DBs will be created for the two sites (example_a and example_b).

And when I run docker-compose up in ./siteA, I want to change current DB to example_a, and initialize the site with a certain amount of data by sql volumed from ./siteA/mysql/setup.sql.

Same thing goes with siteB.

I know I can specify a database and volume like -
WORDPRESS_DB_NAME: example_a and - ./db-data/mysql.dump.sql:/docker-entrypoint-initdb.d/install_wordpress.sql in mysql section in docker-compose.yml but I only have one shared mysql and cannot specify DB and volume for each site.

I have multiple docker-compose.yml files look something like below.

./shared/docker-compose.yml

version: "2"

services:

 proxy:
 image: jwilder/nginx-proxy
 privileged: true
 container_name: proxy
 ports:
 - 80:80
 - 443:443
 volumes:
 - /var/run/docker.sock:/tmp/docker.sock:ro
 - ./certs:/etc/nginx/certs:ro
 restart: always
 logging:
 options:
 max-size: 5m
 max-file: "10"

 mysql:
 image: mysql:5.7
 container_name: mysql
 command: >
 --character-set-server=utf8mb4
 --collation-server=utf8mb4_general_ci
 --max-allowed-packet=128M
 ports:
 - "3306:3306"
 environment:
 - MYSQL_ROOT_PASSWORD=foobar
 restart: always
 volumes:
 - db-data:/var/lib/mysql
 - ./mysql/sql-setup.sql:/docker-entrypoint-initdb.d/sql-setup.sql # to create multiple databases (e.g. example_a, example_b)
 logging:
 options:
 max-size: 5m
 max-file: "10"

volumes:
 db-data:
 driver: local

networks:
 default:
 external:
 name: shared

./siteA/docker-compose.yml

version: "2"

services:
 example_a_wordpress:
 image: wordpress
 container_name: a.example
 environment:
 WORDPRESS_DB_NAME=example_a
 WORDPRESS_DB_PASSWORD=foobar
 VIRTUAL_HOST: a.example.dev
 external_links:
 - mysql
 restart: always
 volumes:
 - ./dist/theme:/var/www/html/wp-content/themes/main
 - ./dist/assets:/var/www/html/assets
 logging:
 options:
 max-size: 5m
 max-file: "10"

networks:
 default:
 external:
 name: shared

./siteB/docker-compose.yml

version: "2"

services:
 example_b_wordpress:
 image: wordpress
 container_name: b.example
 environment:
 WORDPRESS_DB_NAME=example_b
 WORDPRESS_DB_PASSWORD=foobar
 VIRTUAL_HOST: b.example.dev
 external_links:
 - mysql
 restart: always
 volumes:
 - ./dist/theme:/var/www/html/wp-content/themes/main
 - ./dist/assets:/var/www/html/assets
 logging:
 options:
 max-size: 5m
 max-file: "10"

networks:
 default:
 external:
 name: shared

Did you try setting up table prefix in wp_config.php

$table_prefix = 'yourcustomname_';

This should resolve the issue with one DB connection on both sites..