我有一个在AWS弹性容器服务(Fargate)中运行confluentinc/cp-schema-registry:5.5.0映像的docker容器。只有一个容器在运行。通过此模式注册中心获取当前注册模式的API调用正在工作(例如GET http://<schema-registry-url>:8081/subjects)。如果我尝试注册一个匹配当前主题定义的模式(例如POST http://<schema-registry-url>:8081/subjects/<my-subject>/versions)，我得到当前主题的ID返回。然而，如果我尝试注册一个全新的主题(例如POSThttp://<schema-registry-url>:8081/subjects/<my-subject-that-doesn't-exist-yet>/versions)，我得到一个500异常和一条消息如下:
{
"error_code": 50004,
"message": "Master not known."
}
尝试删除现有架构版本同样失败。docker容器的日志显示如下:
[2021-01-15 22:09:57,855] ERROR Request Failed with exception (io.confluent.rest.exceptions.DebuggableExceptionMapper)
io.confluent.kafka.schemaregistry.rest.exceptions.RestUnknownMasterException: Master not known.
at io.confluent.kafka.schemaregistry.rest.exceptions.Errors.unknownMasterException(Errors.java:114)
at io.confluent.kafka.schemaregistry.rest.resources.SubjectVersionsResource.register(SubjectVersionsResource.java:281)
at sun.reflect.GeneratedMethodAccessor6.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.lambda$static$0(ResourceMethodInvocationHandlerFactory.java:52)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:124)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:167)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$VoidOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:159)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:79)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:469)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:391)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:80)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:253)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:248)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:244)
at org.glassfish.jersey.internal.Errors.process(Errors.java:292)
at org.glassfish.jersey.internal.Errors.process(Errors.java:274)
at org.glassfish.jersey.internal.Errors.process(Errors.java:244)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:265)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:232)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:680)
at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:394)
at org.glassfish.jersey.servlet.ServletContainer.serviceImpl(ServletContainer.java:386)
at org.glassfish.jersey.servlet.ServletContainer.doFilter(ServletContainer.java:561)
at org.glassfish.jersey.servlet.ServletContainer.doFilter(ServletContainer.java:502)
at org.glassfish.jersey.servlet.ServletContainer.doFilter(ServletContainer.java:439)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1604)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:545)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1607)
at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1297)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:485)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1577)
at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1212)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
at org.eclipse.jetty.server.handler.StatisticsHandler.handle(StatisticsHandler.java:173)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:221)
at org.eclipse.jetty.server.handler.gzip.GzipHandler.handle(GzipHandler.java:767)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
at org.eclipse.jetty.server.Server.handle(Server.java:500)
at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383)
at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:547)
at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375)
at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:270)
at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)
at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)
at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:388)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:806)
at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:938)
at java.lang.Thread.run(Thread.java:748)
Caused by: io.confluent.kafka.schemaregistry.exceptions.UnknownMasterException: Register schema request failed since master is unknown
at io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.registerOrForward(KafkaSchemaRegistry.java:546)
at io.confluent.kafka.schemaregistry.rest.resources.SubjectVersionsResource.register(SubjectVersionsResource.java:263)
... 59 more
这是在已部署的环境中。我机器上的本地docker容器具有与已部署版本相同的环境变量，将成功注册新的模式主题。
我杀死了正在运行的Task，让ECS Service启动一个新的容器，它开始工作。我没有深入研究日志，以查看容器中的某些内容在何时何地被损坏，但至少现在杀死并创建一个新容器可以解决这个问题。
在基于RPM/Zip文件的自管理Confluent Platform Kafka集群上，只需在所有运行它的节点上逐个执行模式注册表进程的滚动重启即可解决此问题。
如果模式注册表实例在负载平衡器后面，可能会发生这种情况，您可能必须找到领导主机并直接指向它才能解决此问题。