If you have two, standalone Docker containers, how do you network between them? I have this setup:
- php/apache
- mariadb
Most of the information I could find on the Web was related to using the command line, or was totally inscrutable. I wanted to set this up in docker-compose.yml so that students could simply download the files and spin up the containers without worrying about configuration. So, for future reference:
You will have a docker-compose.yml file for each of the containers, and you need to simply add the shared network to each. In this case, we will create a shared network named phpdev:
container 1:
services:
mariadb:
image: "mariadb:latest"
restart: 'always'
ports:
- '${LOCAL_MYSQL_PORT}:3306'
volumes:
- ${LOCAL_MARIADB_DATA_DIR}:${MARIADB_DATA_DIR}
env_file:
- ${LOCAL_ENV_FILE}
environment:
MYSQL_ALLOW_EMPTY_PASSWORD: ${MYSQL_ALLOW_EMPTY_PASSWORD}
MYSQL_ROOT_PASSWORD: ${MYSQL_ROOT_PASSWORD}
networks:
default:
name: phpdev
container 2:
services:
httpd:
image: "php:7.4-apache"
restart: 'no'
ports:
- '${LOCAL_HTTP_PORT}:80'
volumes:
- ${LOCAL_DOCUMENT_ROOT}:/var/www
build:
context: .
dockerfile: ./Dockerfile
networks:
default:
name: phpdev
The first container you spin up will create the network; the second will attach to it. Now, both containers are attached to the phpdev network, and the PHP/Apache container can make requests to the MariaDB container. Specifically, while creating a Database Connection:
// use the container service name as the host
$dbh = new PDO('mysql:host=mariadb;dbname=mydb', 'username', 'mypass');
Took a while to figure this out, but it works nicely.