Known Issues in Streams Messaging

Learn about the known issues in Streams Messaging clusters, the impact or changes to the functionality, and the workaround.

Kafka

Learn about the known issues and limitations in Kafka in this release:

Known Issues

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

Limitations

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:
  1. Obtain the Kafka service name:
    1. In Cloudera Manager, Select the Kafka service.
    2. Select any available chart, and select Open in Chart Builder from the configuration icon drop-down.
    3. Find $SERVICENAME= near the top of the display.
      The Kafka service name is the value of $SERVICENAME.
  2. Turn off the collection of partition level metrics:
    1. Go to Hosts > Hosts Configuration.
    2. 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]_feature_send_broker_topic_partition_entity_update_enabled=false
      
      Replace [KAFKA_SERVICE_NAME] with the service name of Kafka obtained in step 1. The service name should always be in lower case.
    3. Click Save Changes.

Schema Registry

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.
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.

OPSAPS-59597: SMM UI logs are not supported by Cloudera Manager
Cloudera Manager does not support the log type used by SMM UI.
Workaround: View the SMM UI logs on the host.
OPSAPS-59828: SMM cannot connect to Schema Registry when TLS is enabled

When TLS is enabled, SMM by default cannot properly connect to Schema Registry.

As a result, when viewing topics in the SMM Data Explorer with the deserializer key or value set to Avro, the following error messages are shown:
  • Error deserializing key/value for partition [***PARTITION***] at offset [***OFFSET***]. If needed, please seek past the record to continue consumption.
  • Failed to fetch value schema versions for topic : '[***TOPIC**]'.
In addition, the following certificate error will also be present the SMM log:
  • javax.net.ssl.SSLHandshakeException: PKIX path building failed:...
Workaround: Additional security properties must be set for SMM.
  1. In Cloudera Manager, select the SMM service.
  2. Go to Configuration.
  3. Find and configure the SMM_JMX_OPTS property.Add the following JVM SSL properties:
    • Djavax.net.ssl.trustStore=[***SMM TRUSTSTORE LOCATION***]
    • Djavax.net.ssl.trustStorePassword=[***PASSWORD***]

Streams Replication Manager

Learn about the known issues and limitations in Streams Replication Manager in this release:

Known Issues

CDPD-22089: 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.
None
CDPD-14019: SRM may automatically re-create deleted topics
If auto.create.topics.enable is enabled, deleted topics are automatically recreated on source clusters.
Prior to deletion, remove the topic from the topic whitelist with the srm-control tool. 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.
CDPD-60823: Configuring the SRM Client's secure storage is mandatory for unsecured environments
In an unsecured environment the srm-control tool should not need any additional configuration to run. However, due to an issue with the automatic generation of the default configuration, configuring the SRM Client's secure storage is mandatory for the srm-control tool. This is true even if none of the clusters that the tool connects to are secured.
If a secure storage is not configured, the tool will fail with the following NullPointerException:
java.lang.NullPointerException
at com.cloudera.dim.mirror.SecureConfigProvider.retrievePassword(SecureConfigProvider.java:99)
at com.cloudera.dim.mirror.SecureConfigProvider.configure(SecureConfigProvider.java:113)
at org.apache.kafka.common.config.AbstractConfig.instantiateConfigProviders(AbstractConfig.java:533)
at org.apache.kafka.common.config.AbstractConfig.resolveConfigVariables(AbstractConfig.java:477)
at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:107)
at org.apache.kafka.common.config.AbstractConfig.<init>(AbstractConfig.java:142)
at org.apache.kafka.connect.mirror.MirrorMakerConfig.<init>(MirrorMakerConfig.java:88)
at com.cloudera.dim.mirror.MirrorControlCommand$SourceTargetCommand.init(MirrorControlCommand.java:97)
at com.cloudera.dim.mirror.MirrorControlCommand.issueCommand(MirrorControlCommand.java:369)
at com.cloudera.dim.mirror.MirrorControlCommand.main(MirrorControlCommand.java:346)
Configure a secure storage password and set it as an environment variable in your CLI session before running the srm-control tool.
  1. In Cloudera Manager, select the Streams Replication Manager service.
  2. Go to Configuration.
  3. Find and configure the SRM Client's Secure Storage Password property.

    Take note of the password that you configure.

  4. Click Save changes.

  5. Restart the SRM service
  6. SSH into one of the SRM hosts in your cluster.
  7. Set the secure storage password as an environment variable.
    export [***SECURE STORAGE ENV VAR***]=”[***SECURE STORAGE PASSWORD***]”
    
    Replace [***SECURE STORAGE ENV VAR***] with the name of the environment variable you specified in Environment Variable Holding SRM Client's Secure Storage Password. Replace [***SRM SECURE STORAGE PASSWORD***] with the password you specified in SRM Client's Secure Storage Password. For example:
    export SECURESTOREPASS=”mypassword”
OPSAPS-61001: Saving configuration changes for SRM is not possible
Cloudera Manager incorrectly labels the SRM Client's Secure Storage Password property as mandatory. Moreover, it does not offer this property for configuration when SRM is installed with the Add Service Wizard.

As a result, it is possible to install and start SRM without configuring this property. However, in a case like this, making changes to SRM's configuration is not possible until the SRM Client's Secure Storage Password property is set.

Configure the SRM Client's Secure Storage Password property.
OPSAPS-60601: The SRM client's secure storage might become corrupted if the JAAS Secret properties are used
Cloudera Manager generates a secure storage for SRM clients that stores the sensitive data (security related properties) needed to access the clusters that SRM replicates. The sensitive data that the secure storage contains is sourced from the Kafka credentials created by the user in the Administration > External Accounts > Kafka Credentials > Add Kafka credentials modal window in Cloudera Manager. If the JAAS Secret properties available in this modal window are used, the generated secure storage can become corrupted. In a case like this, the JAAS configuration is only partially saved to the configuration.
Specify the JAAS configuration using the Streams Replication Manager’s Replication Configs Cloudera Manager property.
This is done by adding the sasl.jaas.config property to Streams Replication Manager’s Replication Configs with an appropriate prefix. For example:
[***ALIAS***].sasl.jaas.config=[***JAAS CONFIG***]

Replace [***ALIAS***] with a cluster alias specified in Streams Replication Manager Cluster alias. Replace [***JAAS CONFIG***] with a valid JAAS configuration. Repeat this process for all clusters that require a JAAS configuration.

OPSAPS-60601: Replication does not start when the target cluster of the replication is unsecured
When replicating data into an unsecured cluster, the configuration generated for SRM will contain references to defined, but otherwise empty environment variables related to TLS/SSL properties (keystore or truststore locations). The values of these variables cannot be processed by SRM. As a result, replication does not start.
Create and use a placeholder truststore file for the unsecured cluster:
  1. Create a placeholder truststore with the keytool utility. For example:
    keytool -genkeypair -alias placeholder -storepass secret -keypass secret -keystore placeholder.jks -dname "CN=Placeholder, OU=Department, O=Company, L=City, ST=State, C=CA"
  2. Copy the resulting placeholder.jks file to the same location on all SRM driver hosts.
  3. Configure SRM to use the keystore for the unsecured cluster.
    This can be done by adding the ssl.truststore.location and ssl.truststore.password properties to the Streams Replication Manager’s Replication Configs Cloudera Manager property with an appropriate prefix. For example:
    [***ALIAS***].ssl.truststore.location=[***TRUSTSTORE LOCATION***]
    [***ALIAS***].ssl.truststore.password=[***TRUSTSTORE PASSWORD***]
    Replace [***ALIAS***] with the unsecured cluster's alias. You can find the alias in Streams Replication Manager Cluster alias. Replace [***TRUSTSTORE LOCATION**] with the location you copied the placeholder.jks file to in Step 2. Replace [***TRUSTSTORE PASSWORD***] with the password you specified when creating the keystore. Repeat this step for all unsecured clusters.
OPSAPS-61814: Using the service dependency method to configure Kerberos enabled co-located clusters is not supported
Using the Streams Replication Manager Co-located Kafka Cluster Alias property to auto-configure the connection to a Kerberos enabled co-located Kafka cluster is not supported. In a case like this, the generated JAAS configuration contains host-specific configuration. This causes SRM to fail to connect to the co-located Kafka cluster on other hosts.
Define your co-located Kafka clusters using Kafka credentials. For more information, see Defining co-located Kafka clusters using Kafka credentials. Alternatively, use the Streams Replication Manager's Replication Configs property to configure the connection to the co-located Kafka clusters.
OPSAPS-60775: Kafka External Accounts configurations are not generated for the SRM Service
Kafka External Account configurations are not generated for SRM Service, making it unable to target clusters defined through External Accounts.
Use the co-located cluster auto-configuration, or the legacy array configuration (Streams Replication Manager’s Replication Configs) to configure the target cluster of SRM Service.
Limitations
SRM cannot replicate Ranger authorization policies to or from Kafka clusters
Due to a limitation in the Kafka-Ranger plugin, SRM cannot replicate Ranger policies to or from clusters that are configured to use Ranger for authorization. If you are using SRM to replicate data to or from a cluster that uses Ranger, disable authorization policy synchronization in SRM. This can be achieved by clearing the Sync Topic Acls Enabled (sync.topic.acls.enabled) checkbox.