Known Issues in Streams Replication Manager
Learn about the known issues in Streams Replication Manager, the impact or changes to the functionality, and the workaround.
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.
- CDPD-11079: Blacklisted topics appear in the list of replicated topics
- If a topic was originally replicated but was later disallowed
(blacklisted), it will still appear as a replicated topic under the
/remote-topics
REST API endpoint. As a result, if a call is made to this endpoint, the disallowed topic will be included in the response. Additionally, the disallowed topic will also be visible in the SMM UI. However, it's Partitions and Consumer Groups will be 0, its Throughput, Replication Latency and Checkpoint Latency will show N/A. - CDPD-30275: SRM may automatically re-create deleted topics on target clusters
- If
auto.create.topics.enable
is enabled, deleted topics might get automatically re-created on target clusters. This is a timing issue. It only occurs if remote topics are deleted while the replication of the topic is still ongoing.
- OPSAPS-63104: The automatically generated password for co-located services is invalid
- SRM automatically generates a username and password that can be used by co-located services to access SRM and its REST API. However, a unique password is generated for each SRM Service role instance. Because of this, co-located services that use the password, for example SMM, can only connect to one of the SRM Service role instances.
- OPSAPS-63992: Rolling restart unavailable for SRM
- Initiating a rolling restart for the SRM service is not possible. Consequently, performing a rolling upgrade of the SRM service is also not possible.
- CDPD-31745: SRM Control fails to configure internal topic when target is earlier than Kafka 2.3
- When the target Kafka cluster of a replication is earlier than
version 2.3, the
srm-control
internal topic is created with an incorrect configuration (cleanup.policy=compact
). This causes thesrm-control
topic to lose the replication filter records, causing issues in the replication. - OPSAPS-67772: SRM Service metrics processing fails when the noexec option is enabled for /tmp
- The SRM Service role uses /tmp to extract
RocksDB .so files, which are required for metrics processing to
function. If the
noexec
option is enabled for the /tmp directory, the SRM Service role is not able load the required RocksDB files. This results in metrics processing failing. - OPSAPS-67738: SRM Service role's Remote Querying feature does not work when the noexec option is enabled for /tmp
-
The SRM Service role puts the Netty native libraries into the /tmp directory. As a result, If the
noexec
option is enabled for the /tmp directory, the Remote Querying feature will fail to function. - OPSAPS-62546: Kafka External Account SSL keypassword configuration is used incorrectly by SRM
- When a Kafka External Account specifies a keystore that uses an
SSL key password, SRM uses it as the
ssl.keystore.key
configuration. Due to using the incorrectssl.keystore.key
configuration, SRM will fail to load the keystore in certain cases.
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. - SRM cannot ensure the exactly-once semantics of transactional source topics
- SRM data replication uses at-least-once guarantees, and as a result cannot ensure the exactly-once semantics (EOS) of transactional topics in the backup/target cluster.
- SRM checkpointing is not supported for transactional source topics
- SRM does not correctly translate checkpoints (committed consumer group offsets) for transactional topics. Checkpointing assumes that the offset mapping function is always increasing, but with transactional source topics this is violated. Transactional topics have control messages in them, which take up an offset in the log, but they are never returned on the consumer API. This causes the mappings to decrease, causing issues in the checkpointing feature. As a result of this limitation, consumer failover operations for transactional topics is not possible.