Hi,
I’m using Kafka kafka_2.11-1.0.0 and the java client version is 0.10.1.0.
The topic has 9 partitions and there are 2 processes each has 5 consumer
threads consuming this topic.
The consumer group indefinitely rebalances after the 2 processes started.
This is the consumer config info
------------------------------------------------
auto.commit.interval.ms = 5000
auto.offset.reset = latest
bootstrap.servers = [172.22.9.1:9092, 172.22.9.4:9092, 172.22.9.3:9092]
check.crcs = true
client.id = consumer-6835
connections.max.idle.ms = 540000
enable.auto.commit = true
exclude.internal.topics = true
fetch.max.bytes = 52428800
fetch.max.wait.ms = 500
fetch.min.bytes = 1
group.id = dmkDPGroup
heartbeat.interval.ms = 3000
interceptor.classes = null
key.deserializer = class
org.apache.kafka.common.serialization.StringDeserializer
max.partition.fetch.bytes = 1048576
max.poll.interval.ms = 300000
max.poll.records = 20
metadata.max.age.ms = 300000
metric.reporters = []
metrics.num.samples = 2
metrics.sample.window.ms = 30000
partition.assignment.strategy = [class
org.apache.kafka.clients.consumer.RangeAssignor]
receive.buffer.bytes = 65536
reconnect.backoff.ms = 50
request.timeout.ms = 305000
retry.backoff.ms = 100
sasl.kerberos.kinit.cmd = /usr/bin/kinit
sasl.kerberos.min.time.before.relogin = 60000
sasl.kerberos.service.name = null
sasl.kerberos.ticket.renew.jitter = 0.05
sasl.kerberos.ticket.renew.window.factor = 0.8
sasl.mechanism = GSSAPI
security.protocol = PLAINTEXT
send.buffer.bytes = 131072
session.timeout.ms = 10000
ssl.cipher.suites = null
ssl.enabled.protocols = [TLSv1.2, TLSv1.1, TLSv1]
ssl.endpoint.identification.algorithm = null
ssl.key.password = null
ssl.keymanager.algorithm = SunX509
ssl.keystore.location = null
ssl.keystore.password = null
ssl.keystore.type = JKS
ssl.protocol = TLS
ssl.provider = null
ssl.secure.random.implementation = null
ssl.trustmanager.algorithm = PKIX
ssl.truststore.location = null
ssl.truststore.password = null
ssl.truststore.type = JKS
value.deserializer = class
org.apache.kafka.common.serialization.StringDeserializer
------------------------------------------------
and this is the log in server(broker)
----------------------------------
[2019-02-28 21:24:54,040] INFO [GroupCoordinator 0]: Stabilized group
dmkDPGroup generation 54334 (__consumer_offsets-27)
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:24:54,043] INFO [GroupCoordinator 0]: Assignment received from
leader for group dmkDPGroup for generation 54334
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:24:54,192] INFO [GroupCoordinator 0]: Preparing to rebalance
group dmkDPGroup with old generation 54334 (__consumer_offsets-27)
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:24:57,150] INFO [GroupCoordinator 0]: Stabilized group
dmkDPGroup generation 54335 (__consumer_offsets-27)
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:24:57,151] INFO [GroupCoordinator 0]: Assignment received from
leader for group dmkDPGroup for generation 54335
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:24:57,273] INFO [GroupCoordinator 0]: Preparing to rebalance
group dmkDPGroup with old generation 54335 (__consumer_offsets-27)
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:25:00,368] INFO [GroupCoordinator 0]: Stabilized group
dmkDPGroup generation 54336 (__consumer_offsets-27)
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:25:00,368] INFO [GroupCoordinator 0]: Assignment received from
leader for group dmkDPGroup for generation 54336
(kafka.coordinator.group.GroupCoordinator)
[2019-02-28 21:25:00,493] INFO [GroupCoordinator 0]: Preparing to rebalance
group dmkDPGroup with old generation 54336 (__consumer_offsets-27)
(kafka.coordinator.group.GroupCoordinator)
----------------------------------
It seems that a rebalance reassignment is received from the consumer group
leader every 3 seconds.
Is there anyone who has ever met such situation?
And my question is, how can I find out who is the consumer group leader and how
can I find out why the group coordinator (the coordinator should a broker, is
it?) thinks there's some consumer has left so it triggers a rebalance?
The GC in consumer is normal (a young GC every several seconds) and I think it
does not impact the sending of heartbeat.
I can provide more log info if needed.
Many thanks in advance!
