Django（容器化）无法连接到本地机器上的 MySQL（容器化）

Question

我在 CentOS 7.6 的虚拟机上通过命令使用来自 DockerHub 的官方镜像设置了一个 MySQL 数据库

docker run -d -p 3306:3306 --name mysql -v /opt/mysql/mysql-data/:/var/lib/mysql -e MYSQL_DATABASE=myblog -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7

然后我在另一个名为myblog容器中使用设置构建并启动了一个 Django 项目

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'myblog',
        'USER': os.environ.get("MYSQL_USER", 'root'),
        'PASSWORD': os.environ.get("MYSQL_PASSWD", '123456'),
        'HOST': os.environ.get("MYSQL_HOST", '127.0.0.1'),
        'PORT': os.environ.get("MYSQL_PORT", '3306')
    }
}

但是，当我打开 Django 项目的交互式 bash shell 并尝试使用命令python3 manage.py makemigrations ，Django 抱怨连接并出现以下异常：

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 583, in connect
    **kwargs)
  File "/usr/lib64/python3.6/socket.py", line 724, in create_connection
    raise err
  File "/usr/lib64/python3.6/socket.py", line 713, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 194, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 227, in get_new_connection
    return Database.connect(**conn_params)
  File "/usr/local/lib/python3.6/site-packages/pymysql/__init__.py", line 94, in Connect
    return Connection(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 325, in __init__
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 630, in connect
    raise exc
pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on '127.0.0.1' ([Errno 111] Connection refused)")

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/__init__.py", line 381, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python3.6/site-packages/django/core/management/__init__.py", line 375, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/base.py", line 316, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/base.py", line 353, in execute
    output = self.handle(*args, **options)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/base.py", line 83, in wrapped
    res = handle_func(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/django/core/management/commands/makemigrations.py", line 103, in handle
    loader.check_consistent_history(connection)
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/loader.py", line 281, in check_consistent_history
    applied = recorder.applied_migrations()
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 61, in applied_migrations
    if self.has_table():
  File "/usr/local/lib/python3.6/site-packages/django/db/migrations/recorder.py", line 44, in has_table
    return self.Migration._meta.db_table in self.connection.introspection.table_names(self.connection.cursor())
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 255, in cursor
    return self._cursor()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 232, in _cursor
    self.ensure_connection()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/django/db/utils.py", line 89, in __exit__
    raise dj_exc_value.with_traceback(traceback) from exc_value
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 216, in ensure_connection
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/base/base.py", line 194, in connect
    self.connection = self.get_new_connection(conn_params)
  File "/usr/local/lib/python3.6/site-packages/django/db/backends/mysql/base.py", line 227, in get_new_connection
    return Database.connect(**conn_params)
  File "/usr/local/lib/python3.6/site-packages/pymysql/__init__.py", line 94, in Connect
    return Connection(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 325, in __init__
    self.connect()
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 630, in connect
    raise exc
django.db.utils.OperationalError: (2003, "Can't connect to MySQL server on '127.0.0.1' ([Errno 111] Connection refused)")

我尝试将MYSQL_HOST更改为localhost或127.0.0.1 （默认情况下）或分配给虚拟机的 WAN ip 地址，但都MYSQL_HOST 。

Answer 1

运行 myblog 容器时将MYSQL_HOST环境变量设置为mysql

例如： -e MYSQL_HOST=mysql run -d -e MYSQL_HOST=mysql --name myblog myblog

如果您使用的是默认网络，则必须使用 --link 选项或为其创建另一个网络：

例如：

1. docker network create mynetwork
2. docker connect mynetwork myblog
3. docker connect mynetwork mysql