Wordpress container just works default credentials - wordpress

Question

I've a question how exactly docker-compose handles environment variables.
services:
wp:
image: wordpress:latest
container_name: "wp"
restart: unless-stopped
links:
- wpdb
environment:
- TZ=Europe/Berlin
- WORDPRESS_DB_HOST=wpdb:3306
- WORDPRESS_DB_USER=wordpress
- WORDPRESS_DB_PASSWORD=password
- WORDPRESS_DB_NAME=wp
volumes:
- ./data:/var/www/html
labels:
- "traefik.enable=true"
- "traefik.backend=wp"
- "traefik.frontend.rule=Host:MASKED"
- "traefik.port=80"
- "traefik.docker.network=web"
networks:
- internal
- web
wpdb:
image: mariadb:latest
restart: unless-stopped
container_name: "wpdb"
environment:
- MYSQL_ROOT_PASSWORD=1234
- MYSQL_USER=wordpress
- MYSQL_PASSWORD=password
- MYSQL_DATABASE=wp
networks:
- internal
labels:
- "traefik.enable=false"
volumes:
- ./sql:/var/lib/mysql
volumes:
data:
sql:
networks:
web:
external: true
internal:
The compose file works great. The containers will be created and work perfectly.
But when I change the defaults at: WORDPRESS_DB_PASSWORD=password and MYSQL_PASSWORD=password.
The Wordpress container throws access denied for user. I also tried to kill the container and volumes.
Hopefully someone has a hint for me.

Answer 1

You should be doing a docker-compose down -v which would delete the named volumes declared in the volumes section. The only downside is that you would be losing all the data created by the service for the first time.
Here is how I could reproduce it -
Used your compose file as reference and on first time used the default password mentioned by you. The services come up fine, I install it and do a Ctrl+C to bring down the service. So all the MYSQL data is written into sql named volume.
When you do a Ctrl+C OR docker-compose down it only removes the containers and networks defined in the service. Not the volumes. Read more about it here
Now when you change password and bring the service back up it still uses the old volumes which has your old password.
So use a docker-compose down -v to remove the volumes too and give it a try.
Here are the steps how I reproduced it
Ctrl+C to stop all the services and then update the docker-compose.yml to update the password and do a docker-compose up again to get access denied error.
Do a docker-compose down -v to clean all the volume too and then do a docker-compose up
On doing a docker-compose down -v you will be losing all the data created by the prior service. Use it cautiously.