postgresql - 重新创建数据库容器时，Debezium源任务无法重新连接到PostgreSQL数据库

Question

我们有一个Kubernetes集群，其中Debezium作为Postgresql的源任务运行并写入kafka。 Debezium，postgres和kafka都在单独的Pod中运行。
当删除postgres pod并kubernetes重新创建pod时，debezium pod无法重新连接。
来自debezium pod的日志:

    2018-07-17 08:31:38,311 ERROR  ||  WorkerSourceTask{id=inventory-connector-0} Task is being killed and will not recover until manually restarted   [org.apache.kafka.connect.runtime.WorkerTask]
    2018-07-17 08:31:38,311 INFO   ||  [Producer clientId=producer-4] Closing the Kafka producer with timeoutMillis = 30000 ms.   [org.apache.kafka.clients.producer.KafkaProducer]

Debezium继续尝试定期刷新未完成的消息，但给出以下异常:

    2018-07-17 08:32:38,167 ERROR  ||  WorkerSourceTask{id=inventory-connector-0} Exception thrown while calling task.commit()   [org.apache.kafka.connect.runtime.WorkerSourceTask]
    org.apache.kafka.connect.errors.ConnectException: org.postgresql.util.PSQLException: Database connection failed when writing to copy
    at io.debezium.connector.postgresql.RecordsStreamProducer.commit(RecordsStreamProducer.java:151)
    at io.debezium.connector.postgresql.PostgresConnectorTask.commit(PostgresConnectorTask.java:138)
    at org.apache.kafka.connect.runtime.WorkerSourceTask.commitSourceTask(WorkerSourceTask.java:437)
    at org.apache.kafka.connect.runtime.WorkerSourceTask.commitOffsets(WorkerSourceTask.java:378)
    at org.apache.kafka.connect.runtime.SourceTaskOffsetCommitter.commit(SourceTaskOffsetCommitter.java:108)
    at org.apache.kafka.connect.runtime.SourceTaskOffsetCommitter.access$000(SourceTaskOffsetCommitter.java:45)
    at org.apache.kafka.connect.runtime.SourceTaskOffsetCommitter$1.run(SourceTaskOffsetCommitter.java:82)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
    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)
    Caused by: org.postgresql.util.PSQLException: Database connection failed when writing to copy
    at org.postgresql.core.v3.QueryExecutorImpl.flushCopy(QueryExecutorImpl.java:942)
    at org.postgresql.core.v3.CopyDualImpl.flushCopy(CopyDualImpl.java:23)
    at org.postgresql.core.v3.replication.V3PGReplicationStream.updateStatusInternal(V3PGReplicationStream.java:176)
    at org.postgresql.core.v3.replication.V3PGReplicationStream.forceUpdateStatus(V3PGReplicationStream.java:99)
    at io.debezium.connector.postgresql.connection.PostgresReplicationConnection$1.doFlushLsn(PostgresReplicationConnection.java:246)
    at io.debezium.connector.postgresql.connection.PostgresReplicationConnection$1.flushLsn(PostgresReplicationConnection.java:239)
    at io.debezium.connector.postgresql.RecordsStreamProducer.commit(RecordsStreamProducer.java:146)
    ... 13 more
    Caused by: java.net.SocketException: Broken pipe (Write failed)
    at java.net.SocketOutputStream.socketWrite0(Native Method)
    at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:111)
    at java.net.SocketOutputStream.write(SocketOutputStream.java:155)
    at java.io.BufferedOutputStream.flushBuffer(BufferedOutputStream.java:82)
    at java.io.BufferedOutputStream.flush(BufferedOutputStream.java:140)
    at org.postgresql.core.PGStream.flush(PGStream.java:553)
    at org.postgresql.core.v3.QueryExecutorImpl.flushCopy(QueryExecutorImpl.java:939)
    ... 19 more

有一种方法可以让Debezium在可用时重新建立其与postgres的连接吗？
还是我缺少一些配置？

Debezium版本0.8

kubernetes版本1.10.3

postgres 9.6版

Answer 1

看起来这是一个常见问题，在debezium和kafka中都有开放功能请求

https://issues.jboss.org/browse/DBZ-248

https://issues.apache.org/jira/browse/KAFKA-5352

虽然这些是开放的，但看起来这是预期的行为

作为解决方法，我已将该 Activity 探针添加到部署中

    livenessProbe:
        exec:
          command:
          - sh
          - -ec
          - ipaddress=$(ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print $2}' | cut -f1  -d'/'); reply=$(curl -s $ipaddress:8083/connectors/inventory-connector/status | grep -o RUNNING | wc -l); if [ $reply -lt 2 ]; then exit 1; fi;
        initialDelaySeconds: 30
        periodSeconds: 5

第一个子句获取容器IP地址:

    ipaddress=$(ip addr | grep 'state UP' -A2 | tail -n1 | awk '{print $2}' | cut -f1 -d'/');

第二个子句发出请求，并计算响应json中“RUNNING”的实例:

    reply=$(curl -s $ipaddress:8083/connectors/inventory-connector/status | grep -o RUNNING | wc -l);

如果“RUNNING”出现少于两次，则第三子句返回退出代码1

    if [ $reply -lt 2 ]; then exit 1; fi

它似乎正在初步测试中工作-即重新启动postgres DB会触发重新启动debezium容器。我猜可以在图像中包含类似这样的脚本(尽管可能是“经过增强的”)，以利于探查。