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.
- 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 excluded for
replication, it will still appear as a replicated topic under the
/remote-topicsREST API endpoint. As a result, if a call is made to this endpoint, this topic will be included in the response. Additionally, the excluded 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.
- OPSAPS-65728: Streams Messaging components do not start - python: command not found
- If the
pythoncommand is not present in the
PATHvariable and is not aliased to
python, Streams Messaging components (Kafka, Schema Registry, Streams Messaging Manager, Streams Replication Manager, and Cruise Control) fail to start.
- Ensure that the
pythoncommand is present in the
PATHvariable and is aliased to
- 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
- 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.