docker 中的 .NET Core 应用程序无法连接到 mysql 服务器

Question

我有一个在 docker 中运行的 .NET Core 应用程序。

对于连接字符串：

 "Server=localhost;port=3306;database=xxxxx;uid=xxxxx;password=xxxxx;"

当它连接到同一个centos服务器上的非docker mysql服务器时， 它显示：

MySql.Data.MySqlClient.MySqlException (0x80004005): Unable to connect to any of the specified MySQL hosts. ---> System.AggregateException: One or more errors occurred. (Connection refused 127.0.0.1:3306) ---> System.Net.Internals.SocketExceptionFactory+ExtendedSocketException: Connection refused 127.0.0.1:3306
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
   at System.Net.Sockets.Socket.MultipleAddressConnectCallback(IAsyncResult result)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.TcpClient.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.TcpClient.<>c.<ConnectAsync>b__28_1(IAsyncResult asyncResult)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at MySql.Data.Common.StreamCreator.GetTcpStream(MySqlConnectionStringBuilder settings)
   at MySql.Data.MySqlClient.NativeDriver.Open()
---> (Inner Exception #0) System.Net.Internals.SocketExceptionFactory+ExtendedSocketException (111): Connection refused 127.0.0.1:3306
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Sockets.Socket.DoMultipleAddressConnectCallback(Object result, MultipleAddressConnectAsyncResult context)
   at System.Net.Sockets.Socket.MultipleAddressConnectCallback(IAsyncResult result)
--- End of stack trace from previous location where exception was thrown ---
   at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.TcpClient.EndConnect(IAsyncResult asyncResult)
   at System.Net.Sockets.TcpClient.<>c.<ConnectAsync>b__28_1(IAsyncResult asyncResult)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)<---

但是我检查了端口 3306 是否处于 LISTEN 状态。 我该如何解决这个问题？

Answer 1

序幕：

好的，我明白了。你需要从 docker 容器中的应用程序直接连接到主机服务。

我曾经解决过这个问题，但最后我更喜欢切换到解决方案： 应用容器+数据库容器

第二个没有问题的选项是：应用容器 + 专用数据库机器（除 docker 主机外）。我绝对建议更改设置。

解决方案 1：

有一个选项可以从 docker 容器连接到主机。但这不是本地主机。将连接字符串更改为（host.docker.internal）：

"Server=host.docker.internal;port=3306;database=xxxxx;uid=xxxxx;password=xxxxx;"

如果您使用的是 linux，请在启动容器时添加 --add-host 选项：

docker run --add-host host.docker.internal:host-gateway <your_image>

解决方案 2（仅限 Linux）：

保持连接字符串不变（或将服务器从 localhost 更改为 127.0.0.1）。

将联网方式改为host：

docker run --network=host <your_image>