Kafka with Confluent Kubernetes Helm Charts = Schema Registr

Question

我的主要问题：为什么模式注册表崩溃？

外围问题：如果我为每个 zookeeper/kafka/schema-registry 配置了一个服务器，为什么每个 pod 都会启动两个 pod？其他一切看起来基本正确吗？

➜  helm repo update
<snip>
➜  helm install --values values.yaml --name my-confluent-oss confluentinc/cp-helm-charts
<snip>
➜  helm list
NAME                REVISION    UPDATED                     STATUS      CHART                   APP VERSION NAMESPACE
my-confluent-oss    1           Sat Oct 20 19:09:08 2018    DEPLOYED    cp-helm-charts-0.1.0    1.0         default  
➜  kubectl get pods
NAME                                                   READY     STATUS             RESTARTS   AGE
my-confluent-oss-cp-kafka-0                            2/2       Running            0          20m
my-confluent-oss-cp-schema-registry-59d8877584-c2jc7   1/2       CrashLoopBackOff   7          20m
my-confluent-oss-cp-zookeeper-0                        2/2       Running            0          20m

我values.yaml如下。我已经用helm install --debug --dry-run测试过了。我只是禁用持久性，设置单个服务器(这是在 VM 中运行的开发设置(，并暂时禁用额外的服务，直到我开始基本工作：

cp-kafka:
brokers: 1
persistence:
enabled: false
cp-zookeeper:
persistence:
enabled: false
servers: 1
cp-zookeeper:
persistence:
enabled: false
servers: 1
cp-kafka-connect:
enabled: false
cp-kafka-rest:
enabled: false
cp-ksql-server:
enabled: false

以下是失败的架构注册表的日志：

➜  kubectl logs my-confluent-oss-cp-schema-registry-59d8877584-c2jc7 cp-schema-registry-server
<snip>
[2018-10-21 00:28:14,738] INFO Kafka version : 2.0.0-cp1 (org.apache.kafka.common.utils.AppInfoParser)
[2018-10-21 00:28:14,738] INFO Kafka commitId : 4b1dd33f255ddd2f (org.apache.kafka.common.utils.AppInfoParser)
[2018-10-21 00:28:14,751] INFO Cluster ID: ofJRwpXzRn-ltDn8b_6h3A (org.apache.kafka.clients.Metadata)
[2018-10-21 00:28:14,753] INFO Initialized last consumed offset to -1 (io.confluent.kafka.schemaregistry.storage.KafkaStoreReaderThread)
[2018-10-21 00:28:14,756] INFO [kafka-store-reader-thread-_schemas]: Starting (io.confluent.kafka.schemaregistry.storage.KafkaStoreReaderThread)
[2018-10-21 00:28:14,800] INFO [Consumer clientId=KafkaStore-reader-_schemas, groupId=my-confluent-oss] Resetting offset for partition _schemas-0 to offset 0. (org.apache.kafka.clients.consumer.internals.Fetcher)
[2018-10-21 00:28:14,821] INFO Cluster ID: ofJRwpXzRn-ltDn8b_6h3A (org.apache.kafka.clients.Metadata)
[2018-10-21 00:28:14,857] INFO Wait to catch up until the offset of the last message at 7 (io.confluent.kafka.schemaregistry.storage.KafkaStore)
[2018-10-21 00:28:14,930] INFO Joining schema registry with Kafka-based coordination (io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry)
[2018-10-21 00:28:14,939] INFO Kafka version : 2.0.0-cp1 (org.apache.kafka.common.utils.AppInfoParser)
[2018-10-21 00:28:14,940] INFO Kafka commitId : 4b1dd33f255ddd2f (org.apache.kafka.common.utils.AppInfoParser)
[2018-10-21 00:28:14,953] INFO Cluster ID: ofJRwpXzRn-ltDn8b_6h3A (org.apache.kafka.clients.Metadata)
[2018-10-21 00:29:14,945] ERROR Error starting the schema registry (io.confluent.kafka.schemaregistry.rest.SchemaRegistryRestApplication)
io.confluent.kafka.schemaregistry.exceptions.SchemaRegistryInitializationException: io.confluent.kafka.schemaregistry.exceptions.SchemaRegistryTimeoutException: Timed out waiting for join group to complete
at io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.init(KafkaSchemaRegistry.java:220)
at io.confluent.kafka.schemaregistry.rest.SchemaRegistryRestApplication.setupResources(SchemaRegistryRestApplication.java:63)
at io.confluent.kafka.schemaregistry.rest.SchemaRegistryRestApplication.setupResources(SchemaRegistryRestApplication.java:41)
at io.confluent.rest.Application.createServer(Application.java:169)
at io.confluent.kafka.schemaregistry.rest.SchemaRegistryMain.main(SchemaRegistryMain.java:43)
Caused by: io.confluent.kafka.schemaregistry.exceptions.SchemaRegistryTimeoutException: Timed out waiting for join group to complete
at io.confluent.kafka.schemaregistry.masterelector.kafka.KafkaGroupMasterElector.init(KafkaGroupMasterElector.java:202)
at io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry.init(KafkaSchemaRegistry.java:215)
... 4 more
[2018-10-21 00:29:14,948] INFO Shutting down schema registry (io.confluent.kafka.schemaregistry.storage.KafkaSchemaRegistry)
[2018-10-21 00:29:14,949] INFO [kafka-store-reader-thread-_schemas]: Shutting down (io.confluent.kafka.schemaregistry.storage.KafkaStoreReaderThread)
[2018-10-21 00:29:14,950] INFO [kafka-store-reader-thread-_schemas]: Stopped (io.confluent.kafka.schemaregistry.storage.KafkaStoreReaderThread)
[2018-10-21 00:29:14,951] INFO [kafka-store-reader-thread-_schemas]: Shutdown completed (io.confluent.kafka.schemaregistry.storage.KafkaStoreReaderThread)
[2018-10-21 00:29:14,953] INFO KafkaStoreReaderThread shutdown complete. (io.confluent.kafka.schemaregistry.storage.KafkaStoreReaderThread)
[2018-10-21 00:29:14,953] INFO [Producer clientId=producer-1] Closing the Kafka producer with timeoutMillis = 9223372036854775807 ms. (org.apache.kafka.clients.producer.KafkaProducer)
[2018-10-21 00:29:14,959] ERROR Unexpected exception in schema registry group processing thread (io.confluent.kafka.schemaregistry.masterelector.kafka.KafkaGroupMasterElector)
org.apache.kafka.common.errors.WakeupException
at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.maybeTriggerWakeup(ConsumerNetworkClient.java:498)
at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:284)
at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:242)
at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:233)
at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.awaitMetadataUpdate(ConsumerNetworkClient.java:161)
at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureCoordinatorReady(AbstractCoordinator.java:243)
at io.confluent.kafka.schemaregistry.masterelector.kafka.SchemaRegistryCoordinator.ensureCoordinatorReady(SchemaRegistryCoordinator.java:207)
at io.confluent.kafka.schemaregistry.masterelector.kafka.SchemaRegistryCoordinator.poll(SchemaRegistryCoordinator.java:97)
at io.confluent.kafka.schemaregistry.masterelector.kafka.KafkaGroupMasterElector$1.run(KafkaGroupMasterElector.java:192)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)

我正在使用minikube 0.30.0和一个全新，干净的minikube vm：

➜  kubectl version
Client Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.5", GitCommit:"32ac1c9073b132b8ba18aa830f46b77dcceb0723", GitTreeState:"clean", BuildDate:"2018-06-22T05:40:33Z", GoVersion:"go1.9.7", Compiler:"gc", Platform:"darwin/amd64"}
Server Version: version.Info{Major:"1", Minor:"10", GitVersion:"v1.10.0", GitCommit:"fc32d2f3698e36b93322a3465f63a14e9f0eaead", GitTreeState:"clean", BuildDate:"2018-03-26T16:44:10Z", GoVersion:"go1.9.3", Compiler:"gc", Platform:"linux/amd64"}

Answer 1

架构注册表无法加入 Kafka 组。您必须检查配置，您的架构注册表最初需要执行领导者选举，并且领导者选举可以通过 Zookeeper 或 Kafka 进行。

看起来 Helm 图表使用 Kafka 领导者选举安装模式注册表，您还可以看到您可以手动传递 Kafka 代理参数或从 中选取它。Values.kafka.bootstrapServers，但 .bootstrapServers 的值也显示为空。您可以通过简单地运行以下内容来查看部署中的配置值：

$ kubectl get deployment my-confluent-oss-cp-schema-registry -o=yaml

然后你可以更改它以指向内部 Kubernetes my-confluent-oss-cp-kafka 服务端点：

$ kubectl edit deployment cp-schema-registry

另外，请注意，在撰写本文时，cp-helm-charts处于开发人员预览版中，因此使用它的风险由您自行承担。

您可以配置的另一个参数是SCHEMA_REGISTRY_KAFKASTORE_INIT_TIMEOUT_CONFIG，因为这正是您看到错误的地方。因此，Kafka 架构注册表可能会在尝试连接到 Kafka 存储时超时。(可能与米尼库贝有关(。奇怪的是它应该重试。