F Méthot created KAFKA-13272:
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Summary: KStream offset stuck with exactly_once after brokers
outage
Key: KAFKA-13272
URL: https://issues.apache.org/jira/browse/KAFKA-13272
Project: Kafka
Issue Type: Bug
Components: streams
Affects Versions: 2.8.0
Environment: Kafka running on Kubernetes
centos
Reporter: F Méthot
Our KStream app offset stay stuck with exactly_once after outage.
Running with KStream 2.8, kafka broker 2.8,
3 brokers.
commands topic is 10 partitions (replication 2, min-insync 2)
command-expiry-store-changelog topic is 10 partitions (replication 2,
min-insync 2)
events topic is 10 partitions (replication 2, min-insync 2)
with this topology
Topologies:
{code:java}
Sub-topology: 0
Source: KSTREAM-SOURCE-0000000000 (topics: [commands])
--> KSTREAM-TRANSFORM-0000000001
Processor: KSTREAM-TRANSFORM-0000000001 (stores: [])
--> KSTREAM-TRANSFORM-0000000002
<-- KSTREAM-SOURCE-0000000000
Processor: KSTREAM-TRANSFORM-0000000002 (stores: [command-expiry-store])
--> KSTREAM-SINK-0000000003
<-- KSTREAM-TRANSFORM-0000000001
Sink: KSTREAM-SINK-0000000003 (topic: events)
<-- KSTREAM-TRANSFORM-0000000002
{code}
h3.
Attempt 1 at reproducing this issue
Our stream app runs with processing.guarantee *exactly_once*
After a Kafka test outage where all 3 brokers pod were deleted at the same time,
Brokers restarted and initialized succesfuly.
When restarting the topology above, one of the tasks would never initialize
fully, the restore phase would keep outputting this messages every few minutes:
{code:java}
2021-08-16 14:20:33,421 INFO stream-thread
[commands-processor-51b0a534-34b6-47a4-bd9c-c57b6ecb8665-StreamThread-1]
Restoration in progress for 1 partitions.
{commands-processor-expiry-store-changelog-8: position=11775908, end=11775911,
totalRestored=2002076}
[commands-processor-51b0a534-34b6-47a4-bd9c-c57b6ecb8665-StreamThread-1]
(org.apache.kafka.streams.processor.internals.StoreChangelogReader)
{code}
Task for partition 8 would never initialize, no more data would be read from
the source commands topic for that partition.
In an attempt to recover, we restarted the stream app with stream
processing.guarantee back to at_least_once, than it proceed with reading the
changelog and restoring partition 8 fully.
But we noticed afterward, for the next hour until we rebuilt the system, that
partition 8 from command-expiry-store-changelog would not be cleaned/compacted
by the log cleaner/compacter compared to other partitions. (could be unrelated,
because we have seen that before)
So we resorted to delete/recreate our command-expiry-store-changelog topic and
events topic and regenerate it from the commands, reading from beginning.
Things went back to normal
h3. Attempt 2 at reproducing this issue
We force-deleted all 3 pod running kafka.
After that, one of the partition can’t be restored. (like reported in previous
attempt)
For that partition, we noticed these logs on the broker
{code:java}
[2021-08-27 17:45:32,799] INFO [Transaction Marker Channel Manager 1002]:
Couldn’t find leader endpoint for partitions Set(__consumer_offsets-11,
command-expiry-store-changelog-9) while trying to send transaction markers for
commands-processor-0_9, these partitions are likely deleted already and hence
can be skipped
(kafka.coordinator.transaction.TransactionMarkerChannelManager){code}
Then
- we stop the kstream app,
- restarted kafka brokers cleanly
- Restarting the Kstream app,
Those logs messages showed up on the kstream app log:
{code:java}
2021-08-27 18:34:42,413 INFO [Consumer
clientId=commands-processor-76602c87-f682-4648-859b-8fa9b6b937f3-StreamThread-1-consumer,
groupId=commands-processor] The following partitions still have unstable
offsets which are not cleared on the broker side: [commands-9], this could be
either transactional offsets waiting for completion, or normal offsets waiting
for replication after appending to local log
[commands-processor-76602c87-f682-4648-859b-8fa9b6b937f3-StreamThread-1]
(org.apache.kafka.clients.consumer.internals.ConsumerCoordinator)
{code}
This would cause our processor to not consume from that specific source
topic-partition.
Deleting downstream topic and replaying data would NOT fix the issue
(EXACTLY_ONCE or AT_LEAST_ONCE)
Workaround found:
Deleted the group associated with the processor, and restarted the kstream
application, application went on to process data normally. (We have resigned to
use AT_LEAST_ONCE for now )
KStream config :
StreamsConfig.RETRY_BACKOFF_MS_CONFIG, 2000
StreamsConfig.REPLICATION_FACTOR_CONFIG, 2
StreamsConfig.COMMIT_INTERVAL_MS_CONFIG, 1000
StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG, 24MB
ConsumerConfig.AUTO_OFFSET_RESET_CONFIG), “earliest”
StreamsConfig.PROCESSING_GUARANTEE_CONFIG, StreamsConfig.EXACTLY_ONCE (now
AT_LEAST_ONCE)
producer.delivery.timeout.ms=120000
consumer.session.timeout.ms=30000
consumer.heartbeat.interval.ms=10000
consumer.max.poll.interval.ms=300000
num.stream.threads=1
We will be doing more of test and I will update the ticket with any findings.
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