Docker / MySQL (utf8mb4)

docker-compose.yml

version: "3"

services:
  db:
    image: mysql:5.7
    container_name: sample-db
    ports:
      - 3344:3306
    volumes:
      - ./db/mysql:/var/lib/mysql
    command:
      [
        "mysqld",
        "--character-set-server=utf8mb4",
        "--collation-server=utf8mb4_bin",
      ]
    environment:
      MYSQL_ROOT_PASSWORD: root
      MYSQL_DATABASE: test
      MYSQL_USER: test
      MYSQL_PASSWORD: test

docker exec -it sample-db bash
mysql -u test -p

# Show character sets
SHOW VARIABLES LIKE '%char%';

# Show collations
SELECT
  DEFAULT_CHARACTER_SET_NAME,
  DEFAULT_COLLATION_NAME 
FROM
  INFORMATION_SCHEMA.SCHEMATA;