关闭 Docker 时分离卷（用于重新启动）

Question

我有一个创建 MySQL 8.0 容器的 Docker Compose（文件名为 my-main-db.yml）：

version: "3.7"
services:
  my-main-db:
    env_file:
      - .env
    image: mysql:8
    container_name: my-main-db
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    ports:
      - 3306:3306
    environment:
      MYSQL_ROOT_PASSWORD: $MY_SERVICE_DB_ROOT_PASSWORD
      MYSQL_DATABASE: my_service_db_local
      MYSQL_USER: $MY_SERVICE_DB_APP_USER
      MYSQL_PASSWORD: $MY_SERVICE_DB_APP_PASSWORD
    volumes:
      - ./my-service-db-data:/var/lib/mysql

要启动它，我运行：

docker-compose -f my-main-db.yml up

它运行得很好，我可以连接到它，也可以通过docker ps看到它运行。

如果我想停止此容器并保留其中的所有数据，我将其关闭：

docker-compose -f my-main-db.yml down

但如果我想停止这个容器并擦除其中的所有数据，以便它以全新的方式启动（并且干净），我的理解是我需要分离或删除体积。所以我一直试图像这样关闭它：

docker-compose -f my-main-db.yml down -v

但是，当我这样做并重新启动它时，我的数据仍然存在，而我希望有一个全新的（空）数据库。

谁能看出我哪里出错了？

Answer 1

docker-compose down -v 将删除命名卷，但它不会删除您作为绑定挂载（如在您的配置中）挂载的目录。为此，您需要自己使用rm -rf。

如果您希望docker-compose 管理卷，请改用命名卷：

version: "3.7"
services:
  my-main-db:
    env_file:
      - .env
    image: mysql:8
    container_name: my-main-db
    command: --default-authentication-plugin=mysql_native_password
    restart: always
    ports:
      - 3306:3306
    environment:
      MYSQL_ROOT_PASSWORD: $MY_SERVICE_DB_ROOT_PASSWORD
      MYSQL_DATABASE: my_service_db_local
      MYSQL_USER: $MY_SERVICE_DB_APP_USER
      MYSQL_PASSWORD: $MY_SERVICE_DB_APP_PASSWORD
    volumes:
      - my-service-db-data:/var/lib/mysql

volumes:
  my-service-db-data:

这将在启动堆栈时自动为您分配一个 docker 卷，并在您运行 docker-compose down -v 时将其删除。

---

例如，如果我在.env 中有以下内容：

MY_SERVICE_DB_ROOT_PASSWORD=secret
MY_SERVICE_DB_APP_USER=myservice
MY_SERVICE_DB_APP_PASSWORD=secret

我可以调出堆栈：

docker-compose up -d

然后连接mysql并建表：

$ mysql -h docker -u myservice -psecret my_service_db_local
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 10
Server version: 8.0.23 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 [my_service_db_local]> create table testtable (id int);
Query OK, 0 rows affected (0.065 sec)

MySQL [my_service_db_local]> show tables;
+-------------------------------+
| Tables_in_my_service_db_local |
+-------------------------------+
| testtable                     |
+-------------------------------+
1 row in set (0.004 sec)

MySQL [my_service_db_local]> ^DBye

现在，如果我使用 -v 降低堆栈：

$ docker-compose down -v
Stopping my-main-db ... done
WARNING: Found orphan containers (docker_test_1) for this project. If you removed or renamed this service in your compose file, you can run this command with the --remove-orphans flag to clean it up.
Removing my-main-db ... done
Removing network docker_default
Removing volume docker_my-service-db-data

...你可以看到Docker已经删除了docker_my-service-db-data 体积。如果我们重新启动堆栈：

$ docker-compose up -d
Creating network "docker_default" with the default driver
Creating volume "docker_my-service-db-data" with default driver
WARNING: Found orphan containers (docker_test_1) for this project. If you removed or renamed this service in your compose file, you can run this command with the --remove-orphans flag to clean it up.
Creating my-main-db ... done

我们可以连接mysql，看到表已经不存在了， 因为数据库是从头开始重新创建的：

$ mysql -h docker -u myservice -psecret my_service_db_local
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.23 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 [my_service_db_local]> show tables;
Empty set (0.004 sec)

MySQL [my_service_db_local]>