docker, MYSQL_ROOT_PASSWORD do not work

Question

docker-compose:

mysql:
image: mysql:5.7.16
container_name: f_mysql
volumes:
  - ./db:/var/lib/mysql
environment:
  MYSQL_ROOT_PASSWORD: sheep
expose:
  - '3306'

and I use docker exec input this container,

and I type echo $MYSQL_ROOT_PASSWORD, then I got sheep,

but the mysql root password still is '',

when I type 'mysql -uroot', I login mysql.

Answer 1

You need to fix your docker-compose file:

environment:
  - MYSQL_ROOT_PASSWORD=sheep

The following is the full docker-compose that achieves what you want:

version: '2'

services:
    mysql:
        image: mysql:5.7.16
        container_name: f_mysql
        volumes:
            - ./db:/var/lib/mysql
        environment:
            - MYSQL_ROOT_PASSWORD=sheep
        expose:
            - '3306'

Then with a docker exec -it f_mysql /bin/bash and inside the container mysql -u root -p, using sheep, as the password, will be the only way to connect to the mysql server.