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Connecting to MySQL DB from node app using sequelize and docker-compose – Phpmyadmin

I am trying to connect a MySQL database which is in a docker container to a node app, which has sequelize installed and is in another container.

I have got a bridge network setup between the 2 containers and the nodeapi container depends on the mysql container.

When I exec into the nodeapi container directly I can connect to the mysql container using the 172.20.0.2 IP address, but this obviously doesn’t work from the host machine. But it does confirm that I can log into the container as expected.

The mysql container is also named – so that means I set the host name of the db in the connection.

The ENV variables load properly which I have confirmed by echo-ing them to the screen when building the container.

The Problem is that I get the following message:

Unable to connect to the database: HostNotFoundError [SequelizeHostNotFoundError]: getaddrinfo ENOTFOUND

The hosts I have tried are:

  • 172.20.0.2 – doesn’t work, since it is the internal IP address
  • localhost – doesn’t work, since the db is not in the nodeapi container
  • 127.0.0.1 – same as previous reason
  • mysqldb – this is what I expect to work, but doesn’t??
  • mysql name of the container in the compose file, doesn’t work.

Can someone please tell me if I have gone work somewhere?

const sequelize = new Sequelize(
  process.env.DB_NAME, 
  process.env.DB_USER, 
  process.env.DB_PASS, {
  host: process.env.DB_HOST,
  dialect: 'mysql'
});

version: "3"

networks:
  app-tier:
    driver: bridge

services:
  mysql: 
    #image: to-jk11/rugby7db:2019-s1
    build:
      context: .
      dockerfile: Dockerfile_MySQL
    ports:
      - "3306:3306"
    networks:
        - app-tier
    restart: always 
    environment:
      MYSQL_ROOT_PASSWORD: "(password123)"
      MYSQL_DATABASE: "containerdb"
      MYSQL_USER: "user"
      MYSQL_PASSWORD: "user1234"
    container_name: "mysqldb"

  phpmyadmin:
    image: phpmyadmin/phpmyadmin
    ports: 
      - "8080:80"
    depends_on:
      - mysql

  nodeapi:
    build:
      context: .
      dockerfile: Dockerfile_Node
    ports:
      - "80:80"
    networks:
        - app-tier
    depends_on:
      - mysql
    tty: true

List of docker networks

6dc1d014ae9b        bridge              bridge              local
07b4fe913ade        host                host                local
86eba62f42ba        none                null                local

Output of network inspect:

[
    {
        "Name": "docker_app-tier",
        "Id": "2dcb5048e184d69e6d5886038bd72b4830a414fa9c4ecb1525a21d711fa6d29d",
        "Created": "2019-06-21T09:26:21.2744912Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.24.0.0/16",
                    "Gateway": "172.24.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": true,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "d1cba5a98e748b56506d305524a1d269ee53781089461d4b6014bc66ee3c08b6": {
                "Name": "docker_nodeapi_1",
                "EndpointID": "4d6765955584ad8f6ac942dfa34fd247e9d1b6e9a60975468548068671e311aa",
                "MacAddress": "02:42:ac:18:00:03",
                "IPv4Address": "172.24.0.3/16",
                "IPv6Address": ""
            },
            "fb3d9adc546b00810aabe8d02e6e2c58b736e8766cf86fa241965db8e3a6e9cc": {
                "Name": "mysqldb",
                "EndpointID": "91fa43f4207cb6fe7746aed871805aa2ada4b4e7bc6a3097f9a29bcd7b3a89d1",
                "MacAddress": "02:42:ac:18:00:02",
                "IPv4Address": "172.24.0.2/16",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {
            "com.docker.compose.network": "app-tier",
            "com.docker.compose.project": "docker",
            "com.docker.compose.version": "1.24.0"
        }
    }
]
Tags:

2

Answers


  1. 0

    Your settings will reuse the default bridge of docker. Try to delete all next in your docker-compose.yaml:

    networks:
  - app-tier

    Or just change next:

    networks:
  app-tier:
    driver: bridge

    to this:

    networks:
  app-tier:

    Then docker-compose will set user-defined bridges for you, see this, the main magic is:

    User-defined bridges provide automatic DNS resolution between containers.

    Then, you can use mysqldb to visit.

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  2. 0

    You should use the container names to connect the different services defined in docker-compose.yml. This can be done using ENV variables passing in the name in lieu of a hostname to your app with something like DATABASE_HOST: mysql – and then your app would need to use process.env.DATABASE_HOST in the connection. You don’t need to mess with your networking config to enable containers to talk to each other.

    ENV vars are how you should do most if not all of the configuration. You may need to do some additional work to have the app container not start until the db is available (like wait-for.sh). Most of the changes to your Dockerfile were made in the environment section of “nodeapi”.

    services:
  mysql: 
    #image: to-jk11/rugby7db:2019-s1
    build:
      context: .
      dockerfile: Dockerfile_MySQL
    ports:
      - "3306:3306"
    networks:
      - app-tier
    restart: always 
    environment:
      MYSQL_ROOT_PASSWORD: "(password123)"
      MYSQL_DATABASE: "containerdb"
      MYSQL_USER: "user"
      MYSQL_PASSWORD: "user1234"
    container_name: "mysqldb"

  phpmyadmin:
    image: phpmyadmin/phpmyadmin
    ports: 
      - "8080:80"
    depends_on:
      - mysql

  nodeapi:
    build:
      context: .
      dockerfile: Dockerfile_Node
    ports:
      - "80:80"
    networks:
        - app-tier
    depends_on:
      - mysql
    tty: true
    environment:
      DATABASE_HOST: mysql
      DATABASE_USER: user
      DATABASE_PASS: user1234
      DATABASE_NAME: containerdb
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