MySQL server in a docker container doesn't work after commiting the container

I created docker-compose.yml file, which creates MySQL image and sets the password of MySQL root user to "hello".

# docker-compose.yml

version: '3.1'

services:

  mysql:
    image: mysql:5.6.40
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    environment:
      - MYSQL_ROOT_PASSWORD=hello
      - MYSQL_ALLOW_EMPTY_PASSWORD=hello
      - MYSQL_RANDOM_ROOT_PASSWORD=hello

Then I run:

sudo docker-compose up # (1)

... from the directory with this file.

The first problem is that the newly created container starts running in the foreground but not in bash and I can't put it in the background without exiting it, which I can do by Ctrl+C, or somehow enter bash, getting out from this process.

But when I open a new terminal window and run:

sudo docker exec -it bdebee1b8090 /bin/bash # (2)

..., where bdebee1b8090 is the id of the running container, I enter bash, where I can enter MySQL shell as root user, entering password "hello":

mysql -u root -p # (3)

Then I exit MySQL shell and bash shell in the container without stopping the container.

And then I commit changes to the container:

sudo docker commit bdebee1b8090 hello_mysql # (4)

..., creating a image. And then, when I run the image:

sudo docker run -it --rm hello_mysql /bin/bash # (5)

... and try to start MySQL shell again as root user, entering password "hello", I get an error like

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

And even after I restart the MySQL server:

/etc/init.d/mysql restart # (6)

..., I get the same error.

All of the above commands were run on ubuntu.

Why is this happening?

Edit:

When I try to make those steps on MacOS High Sierra, I get stuck on the step (3), because when I try to enter the password "hello", it doesn't get accepted. This error is shown on the screen:

ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

And when I try to restart MySQL server in the container

/etc/init.d/mysql restart

..., the container restarts in the background

..., but when I run it again and try to repeat steps (2) and (3) it gives the same error, and when I restart the MySQL server again, the container restarts in the background again...

Edit2:

After I removed lines:

  - MYSQL_ALLOW_EMPTY_PASSWORD=hello
  - MYSQL_RANDOM_ROOT_PASSWORD=hello      - 

...it started to work on Mac, but still after I commit the container, and try to enter the MySQL shell, it gives and error like:

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)

.... again.