Known Issues in Apache Kafka

Known Issues

OPSAPS-59553: SMM's bootstrap server config should be updated based on Kafka's listeners

SMM does not show any metrics for Kafka or Kafka Connect when multiple listeners are set in Kafka.

Workaround: SMM cannot identify multiple listeners and still points to bootstrap server using the default broker port (9093 for SASL_SSL). You would have to override bootstrap server URL (hostname:port as set in the listeners for broker) in the following path:

Cloudera Manager > SMM > Configuration > Streams Messaging Manager Rest Admin Server Advanced Configuration Snippet (Safety Valve) for streams-messaging-manager.yaml > Save Changes > Restart SMM.

Topics created with the kafka-topics tool are only accessible by the user who created them when the deprecated --zookeeper option is used

By default all created topics are secured. However, when topic creation and deletion is done with the kafka-topics tool using the --zookeeper option, 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 --zookeeper option 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.

Use kafka-topics with the --bootstrap-server option 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:

• kafka-reassign-partitions

None

The offsets.topic.replication.factor property must be less than or equal to the number of live brokers

The offsets.topic.replication.factor broker configuration is now enforced upon auto topic creation. Internal auto topic creation will fail with a GROUP_COORDINATOR_NOT_AVAILABLE error until the cluster size meets this replication factor requirement.

None

Requests fail when sending to a nonexistent topic with auto.create.topics.enable set to true

The first few produce requests fail when sending to a nonexistent topic with auto.create.topics.enable set to true.

Increase the number of retries in the producer configuration setting retries.

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.

None

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.

None

OPSAPS-63640: Monitoring a high number of Kafka producers might cause Cloudera Manager to slow down and run out of memory

This issue has two workarounds. You can either configure a Kafka producer metric allow list or completely disable producer metrics.

• Configure a Kafka producer metric allow list:
  A producer metric allow list can be configured by adding the following properties to Kafka Broker Advanced Configuration Snippet (Safety Valve) for kafka.properties.

  producer.metrics.whitelist.enabled=true
  producer.metrics.whitelist=[***ALLOW LIST REGEX***]

  Replace [***ALLOW LIST REGEX***] with a regular expression matching the client.id of the producers that you want to add to the allow list. This regular expression uses the java.util.regex.Pattern class to compile the regular expression, and uses the match() method on the client.id to determine whether it fits the regular expression.

  Once configured, the metrics of producers whose client.id does not match the regular expression provided in producer.metrics.whitelist are filtered.Kafka no longer reports these metrics through the HTTP metrics endpoint. Additionally, existing metrics of the producers whose client.id does not match the regular expression are deleted.

  Because the allow list filters metrics based on the client.id of the producers, you must ensure that the client.id property is specified in each producer's configuration. Automatically generated client IDs might cause the number of unnecessary metrics to increase even if an allow list is configured.

• Completely disable producer metrics:

  Producer metrics can be completely disabled by unchecking the Enable Producer Metrics Kafka service property.

Unsupported Features

The following Kafka features are not supported in Cloudera Data Platform:

• Only Java and .Net based clients are supported. Clients developed with C, C++, Python, and other languages are currently not supported.
• While Kafka Connect is available as part of Runtime, it is currently not supported in CDP Public Cloud. NiFi is a proven solution for batch and real time data loading that complement Kafka's message broker capability. For more information, see Creating your first Flow Management cluster.
• The Kafka default authorizer is not supported. This includes setting ACLs and all related APIs, broker functionality, and command-line tools.

Limitations