How can I connect from `project` to `mysql` container in docker swarm? - docker

Question

I am trying to deploy a stack with the docker swarm with the following configuration docker-compose.yaml file as below via the command:
docker stack deploy --with-registry-auth -c docker-compose.yaml project
version: "3.9"
services:
mysql:
image: mysql:8.0
deploy:
replicas: 1
volumes:
- mysql_data:/var/lib/mysql
networks:
- internal
ports:
- 3306:3306
environment:
MYSQL_ROOT_HOST: '%'
MYSQL_ROOT_PASSWORD: root
MYSQL_DATABASE: project_production
MYSQL_USER: username
MYSQL_PASSWORD: password
es01:
image: docker.elastic.co/elasticsearch/elasticsearch:7.13.4
environment:
- node.name=es01
- cluster.name=es-docker-cluster
- discovery.seed_hosts=es02,es03
- cluster.initial_master_nodes=es01,es02,es03
- bootstrap.memory_lock=true
- "ES_JAVA_OPTS=-Xms1024m -Xmx1024m"
ulimits:
memlock:
soft: -1
hard: -1
volumes:
- data01:/usr/share/elasticsearch/data
ports:
- 9200:9200
networks:
- internal
website:
image: registry.gitlab.com/project/project-website:latest
networks:
- internal
deploy:
replicas: 1
ports:
- 3000:3000
environment:
- RAILS_ENV=production
- MYSQL_HOST=mysql
- ES_HOST=http://es01
- project_DATABASE_USERNAME=root
- project_DATABASE_PASSWORD=root
depends_on:
- es01
- mysql
volumes:
data01:
driver: local
data02:
driver: local
data03:
driver: local
mysql_data:
networks:
internal:
external: true
name: project
Before I deploy the stack I also have created the network for the project via the following command:
docker network create -d overlay project
But when I see the logs for the project using docker logs command I see the following error stops my project get started:
Mysql2::Error: Host '10.0.2.202' is not allowed to connect to this MySQL server
I went exactly as the documents suggested I am not sure what is wrong with the settings that I have come up!
Question:
How can I connect from project to mysql container in docker swarm?

Answer 1

Based on the documentation, Docker Swarm automatically creates the overlay network for you. So I think you don't need to create an external network by default, unless you have specific needs:
When you initialize a swarm or join a Docker host to an existing swarm, two new networks are created on that Docker host:
an overlay network called ingress, which handles the control and data traffic related to swarm services. When you create a swarm service and do not connect it to a user-defined overlay network, it connects to the ingress network by default.
a bridge network called docker_gwbridge, which connects the individual Docker daemon to the other daemons participating in the swarm.
As Chris also mentioned in the comments, the DB credentials also don't match.
OPTIONAL: MYSQL_ROOT_HOST is only necessary if you want to connect as root user which is not recommended in production environments. There's also no need to expose the port to the host machine since the database service will only be used from inside the cluster. So if you still want to use root user, you can set the variable to allow connections only from inside the cluster, like MYSQL_ROOT_HOST=10.*.*.*.