Installing MySQL in Docker fails with error message “Can't connect to local MySQL server through socket”

Question

I\'m trying to install mysql inside a docker container,Tried various images from github, it seems they all manage to successfully install the mysql but when I try to run the

Answer 1

Assuming you're using docker-compose, where your docker-compose.yml file looks like:

version: '3.7'
services:
  mysql_db_container:
    image: mysql:latest
    command: --default-authentication-plugin=mysql_native_password
    environment:
      MYSQL_ROOT_PASSWORD: rootpassword
    ports:
      - 3307:3306
    volumes:
      - mysql_db_data_container:/var/lib/mysql


  web:
    image: ${DOCKER_IMAGE_NAME-eis}:latest
    build:
      context: .
    links:
      - mysql_db_container
    ports:
      - 4000:3000
    command: ["./scripts/wait-for-it.sh", "mysql_db_container:3306", "--", "./scripts/start_web_server.sh"]
    volumes:
      - .:/opt/eis:cached
    env_file:
      - .env

volumes:
  mysql_db_data_container:

Notice the ports definition for mysql_db_container

    ports:
      - 3307:3306

<= That indicates that mysql will be accessible via port 3307 to the localhost workstation and via port 3306 within the docker net

Run the following to see your container names:

$ dc config --services
mysql_db_container
web

In this case, we have two containers.

Errors

If you connect to mysql_db_container from your localhost workstation and try to access the mysql console there, you'll get that error:

docker-compose run mysql_db_container bash
root@8880ffe47962:/# mysql -u root -p
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)
root@8880ffe47962:/# exit

Also, if you try to connect from your local workstation, you'll also get that error:

$ mysql -u root -p -P 3307
Enter password: 
ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

Solutions

Connecting from local workstation

Just add the --protocol=tcp parameter (otherwise mysql assumes you want to connect via the mysql socket):

$ mysql --protocol=tcp -u root -p -P 3307
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 11
Server version: 8.0.21 MySQL Community Server - GPL

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

Connecting from web container

Reference the docker hostname -h mysql_db_container. Note that when you're running within the context of Docker that the TCP protocol is assumed.

$ dc run web bash
Starting eligibility-service_mysql_db_container_1_d625308b5a77 ... done
root@e7852ff02683:/opt/eis# mysql -h mysql_db_container -u root -p
Enter password: 
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 18
Server version: 8.0.21 MySQL Community Server - GPL

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MySQL [(none)]> 

Connecting from mysql container

Assuming your mysql container name is eis_mysql_db_container_1_d625308b5a77 (that you can see when running docker ps), the following should work:

$ docker exec -it eis_mysql_db_container_1_d625308b5a77 bash
root@3738cf6eb3e9:/# mysql -u root -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 19
Server version: 8.0.21 MySQL Community Server - GPL

Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>