Mysql is in it's own docker-compose.yml as I want a mysql server up and running that any other php application can connect to. So I do not have php and mysql in the same docker-compose.yml. From the php application, I can connect to mysql if I use the mysql container's gateway ip address by looking it up and then hard coding it into the php application. docker inspect mysql-db. But docker will change that 172... ip address each time mysql restarts so that is not ideal for development.
I can connect to mysql via mysql -h 127.0.0.1 no problem, but from the php application if I try to use 127.0.0.1 I get connection refused. I can only connect if I use the 172... gateway ip address.
How do I get the mysql container listening for connections from the host to 127.0.0.1?
docker-compose.yml for mysql
version: "3"
services:
mysql:
container_name: mysql-db
image: mysql
build:
dockerfile: Dockerfile
context: ./server/mysql
environment:
- MYSQL_ROOT_PASSWORD=admin
volumes:
- ./data/mysql:/var/lib/mysql
ports:
- 3306:3306
docker-compose.yml for php
version: "3"
services:
nginx:
container_name: nginx_myapp
image: nginx
build:
dockerfile: Dockerfile
context: ./server/nginx
ports:
- 80:80
- 443:443
volumes:
- ./app:/var/www/html
networks:
- myapp
php:
container_name: php_myapp
image: php:7.3-fpm
build:
dockerfile: Dockerfile
context: ./server/php-fpm
environment:
CI_ENV: development
volumes:
- ./app:/var/www/html
networks:
- myapp
networks:
myapp:
127.0.0.1 is the loopback address. It points to localhost. In the context of docker, localhost is the container itself. There is no db running on your php container so the connection will never succeed.
What you need to do is to configure the default network in you mysql compose file so that you will predictably control its name for later convenience (else it will be calculated from your compose project name which could change if you rename the containing folder...):
Important note: for the below to work, you need to use compose file version >= 3.5
---
version: '3.7'
#...
networks:
default:
name: shared_mysql
You can now use that shared_mysql network as external from any other compose project.
version: '3.7'
services:
nginx:
#...
networks:
- myapp
php:
#...
networks:
- myapp
- database
networks:
myapp:
database:
external: true
name: shared_mysql
You can then connect to mysql from your php container using the service name mysql (e.g. mysql -h mysql -u user -p)
Reference: https://docs.docker.com/compose/networking/