Known Issues in Streams Messaging
Learn about the known issues Streams Messaging, the impact or changes to the functionality, and the workaround.
Learn about the known issues and limitations in Kafka in this release:
- Topics created with the
kafka-topicstool are only accessible by the user who created them when the deprecated
--zookeeperoption is used
- By default all created topics are secured. However, when topic
creation and deletion is done with the kafka-topics tool using the
--zookeeperoption, the tool talks directly to Zookeeper. Because security is the responsibility of ZooKeeper authorization and authentication, Kafka cannot prevent users from making ZooKeeper changes. As a result, if the
--zookeeperoption is used, only the user who created the topic will be able to carry out administrative actions on it. In this scenario Kafka will not have permissions to perform tasks on topics created this way.
--bootstrap-serveroption that does not require direct access to Zookeeper.
- Certain Kafka command line tools require direct access to Zookeeper
- The following command line tools talk directly to ZooKeeper and
therefore are not secured via Kafka:
offsets.topic.replication.factorproperty must be less than or equal to the number of live brokers
offsets.topic.replication.factorbroker configuration is now enforced upon auto topic creation. Internal auto topic creation will fail with a
GROUP_COORDINATOR_NOT_AVAILABLEerror until the cluster size meets this replication factor requirement.
- Requests fail when sending to a nonexistent topic with
auto.create.topics.enableset to true
- The first few
producerequests fail when sending to a nonexistent topic with
auto.create.topics.enableset to true.
- Increase the number of retries in the producer
- Custom Kerberos principal names cannot be used for kerberized ZooKeeper and Kafka instances
- When using ZooKeeper authentication and a custom Kerberos principal, Kerberos-enabled Kafka does not start. You must disable ZooKeeper authentication for Kafka or use the default Kerberos principals for ZooKeeper and Kafka.
- KAFKA-2561: Performance degradation when SSL Is enabled
- In some configuration scenarios, significant performance degradation can occur when SSL is enabled. The impact varies depending on your CPU, JVM version, Kafka configuration, and message size. Consumers are typically more affected than producers.
- Configure brokers and clients with
ssl.secure.random.implementation = SHA1PRNG. It often reduces this degradation drastically, but its effect is CPU and JVM dependent.
- OPSAPS-43236: Kafka garbage collection logs are written to the process directory
- By default Kafka garbage collection logs are written to the agent process directory. Changing the default path for these log files is currently unsupported.
- Collection of Partition Level Metrics May Cause Cloudera Manager’s Performance to Degrade
If the Kafka service operates with a large number of partitions, collection of partition level metrics may cause Cloudera Manager's performance to degrade.If you are observing performance degradation and your cluster is operating with a high number of partitions, you can choose to disable the collection of partition level metrics.Complete the following steps to turn off the collection of partition level metrics:
- Obtain the Kafka service name:
- In Cloudera Manager, Select the Kafka service.
- Select any available chart, and select Open in Chart Builder from the configuration icon drop-down.
$SERVICENAME=near the top of the display.The Kafka service name is the value of
- Turn off the collection of partition level metrics:
- Go to .
- Find and configure the Cloudera Manager Agent Monitoring Advanced
Configuration Snippet (Safety Valve) configuration
property.Enter the following to turn off the collection of partition level metrics:
[KAFKA_SERVICE_NAME]with the service name of Kafka obtained in step 1. The service name should always be in lower case.
- Click Save Changes.
- Obtain the Kafka service name:
There are no known issues in Schema Registry in this release.
Streams Messaging Manager
Learn about the known issues in Streams Messaging Manager in this release:
- CDPD-19495: SMM UI does not show producer data on topics page
In the SMM UI, the topics page, the topic profile pages, and the broker profile pages consistently show 0 for producer messages.
Workaround: For the real producer metrics, check the aggregated REST API responses. The real producer metrics are within the producerIdToOutMessagesCount field.
Streams Replication Manager
Learn about the known issues in Streams Replication Manager in this release:
- MM2-163: SRM does not sync re-created source topics until the offsets have caught up with target topic
- Messages written to topics that were deleted and re-created are not replicated until the source topic reaches the same offset as the target topic. For example, if at the time of deletion and re-creation there are a 100 messages on the source and target clusters, new messages will only get replicated once the re-created source topic has 100 messages. This leads to messages being lost.
- CDPD-14019: SRM may automatically re-create deleted topics
auto.create.topics.enableis enabled, deleted topics are automatically recreated on source clusters.
- Prior to deletion, remove the topic from the topic
whitelist with the
srm-controltool. This prevents topics from being re-created.
srm-control topics --source [SOURCE_CLUSTER] --target [TARGET_CLUSTER] --remove [TOPIC1][TOPIC2]
- CDPD-13864 and CDPD-15327: Replication stops after the network configuration of a source or target cluster is changed
- If the network configuration of a cluster which is taking part in a replication flow is changed, for example, port numbers are changed as a result of enabling or disabling TLS, SRM will not update its internal configuration even if SRM is reconfigured and restarted. From SRM’s perspective, it is the cluster identity that has changed. SRM cannot determine whether the new identity corresponds to the same cluster or not, only the owner or administrator of that cluster can know. In this case, SRM tries to use the last known configuration of that cluster which might not be valid, resulting in the halt of replication.
- The internal topic storing the configuration of SRM can be
deleted. After a restart SRM will re-create and re-populate it with the configuration
data loaded from its property file. The topic is hosted on the target cluster of the
replication flow. The topic name is:
mm2-configs.[SOURCE_ALIAS].internal. However, changing a replicated cluster's identity is generally not recommended.
- SRM Cannot Replicate ACLs to or from Kafka Clusters that are Configured with Sentry
- When Sentry contains Kafka authorization
policies for any
ConsumerGroupresource, SRM cannot replicate authorization rules from one Kafka cluster to another in environments where Sentry is enabled. This is due to a Kafka resource conversion error in Sentry. For more information regarding the underlying Sentry issue, see SENTRY-2535 and the Kafka known issues in CDH Known Issues.
- Disable authorization policy synchronization in SRM. This
can be achieved by setting the
sync.topic.acls.enabledproperty to false.