Event Hub报错“No such host is known”问题排查求助

问题背景 #

我订阅了Azure Event Hub以获取消息，使用的C#代码如下：

BlobContainerClient storageClient = new BlobContainerClient(new Uri(serviceConfig.BlobContainerName), certificate);

var processor = new EventProcessorClient
(
    storageClient,
    EventHubConsumerClient.DefaultConsumerGroupName,
    eventHubNamespace,
    eventHubName,
    certificate
);

processor.ProcessEventAsync += ProcessEventHandler;
processor.ProcessErrorAsync += ProcessErrorHandler;

await processor.StartProcessingAsync();

错误详情 #

运行代码时触发错误，核心异常信息：

eventArgs.Exception.Message: No such host is known

错误发生在操作：Retrieving list of partition identifiers from a Consumer Client

完整堆栈跟踪：

[EventHubListener] error StackTrace    at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Azure.Amqp.AsyncResult.End[TAsyncResult](IAsyncResult result)
   at Microsoft.Azure.Amqp.Transport.AmqpTransportInitiator.<>c.<ConnectAsync>b__17_1(IAsyncResult r)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncCoreLogic(IAsyncResult iar, Func`2 endFunction, Action`1 endAction, Task`1 promise, Boolean requiresSynchronization)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Messaging.EventHubs.Amqp.AmqpConnectionScope.<CreateAndOpenConnectionAsync>d__80.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Amqp.FaultTolerantAmqpObject`1.<OnCreateAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Azure.Amqp.Singleton`1.<GetOrCreateAsync>d__24.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Azure.Amqp.Singleton`1.<GetOrCreateAsync>d__24.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Messaging.EventHubs.Amqp.AmqpConnectionScope.<OpenManagementLinkAsync>d__76.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Azure.Amqp.FaultTolerantAmqpObject`1.<OnCreateAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Azure.Amqp.Singleton`1.<GetOrCreateAsync>d__24.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Microsoft.Azure.Amqp.Singleton`1.<GetOrCreateAsync>d__24.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Azure.Messaging.EventHubs.Amqp.AmqpClient.<GetPropertiesAsync>d__30.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Azure.Messaging.EventHubs.Amqp.AmqpClient.<GetPropertiesAsync>d__30.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Messaging.EventHubs.EventHubConnection.<GetPropertiesAsync>d__37.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Messaging.EventHubs.EventHubConnection.<GetPartitionIdsAsync>d__38.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Azure.Messaging.EventHubs.Primitives.EventProcessor`1.<ListPartitionIdsAsync>d__83.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at Azure.Messaging.EventHubs.Primitives.EventProcessor`1.<RunProcessingAsync>d__87.MoveNext()

已执行的测试 #

在部署代码的机器上运行了网络连通性测试命令：

.\psping.exe -n 25 -i 1 -q .servicebus.windows.net:5671 -nobanner

测试结果显示所有请求均超时。

身份验证说明：使用分配了Event Hub Owner/Reader/Writer角色的服务主体，通过证书进行身份验证。

排查与解决建议 #

• 核对Event Hub命名空间地址：确认eventHubNamespace变量的值格式为{你的命名空间}.servicebus.windows.net，检查是否存在拼写错误、前缀缺失或格式错误，这是DNS解析失败的最常见原因。
• 验证DNS解析能力：
  • 在部署机器上执行nslookup {你的命名空间}.servicebus.windows.net，确认能正常解析到Azure的IP地址。若解析失败，检查机器DNS服务器配置，尝试切换到公共DNS（如8.8.8.8）测试。
  • 企业内网环境下，确认防火墙或代理是否拦截了DNS请求，需将Azure Event Hub域名加入允许列表。
• 修正网络连通性测试：将测试命令中的.替换为实际命名空间前缀，执行.\psping.exe -n 25 -i 1 -q {你的命名空间}.servicebus.windows.net:5671 -nobanner，验证5671端口（AMQP协议端口）的出站连通性。内网环境需确认防火墙是否开放该端口的出站流量，或是否需要通过代理连接。
• 检查证书与身份配置：
  • 确认证书未过期、密钥用法正确，且代码中使用的证书指纹与服务主体配置的一致。
  • 通过Azure门户"访问控制(IAM)"页面，验证服务主体的Event Hub角色分配是否正确应用到目标资源（命名空间或具体Event Hub）。
• 更新SDK版本：确保使用的Azure.Messaging.EventHubs和Azure.Storage.Blobs NuGet包为最新稳定版本，旧版本可能存在已知的连接或DNS解析问题。

内容的提问来源于stack exchange，提问作者Catalin