版本：flink版本: flink-1.7.1
kafka客户端版本: flink-connector-kafka-0.11_2.12
kafka服务端版本2.0.0或者1.0.1
flink未启用checkpoint机制，kafka的都是默认配置，offset保存在kafka上
flink-kafka-connector启动参数设置如下：
auto.commit.interval.ms = 5000
auto.offset.reset = earliest
bootstrap.servers = [ip:9092]
check.crcs = true
client.id =
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 = test_user_action_sdb_java2
heartbeat.interval.ms = 3000
interceptor.classes = null
internal.leave.group.on.close = true
isolation.level = read_uncommitted
key.deserializer = class
org.apache.kafka.common.serialization.StringDeserializer
max.partition.fetch.bytes = 1048576
max.poll.interval.ms = 300000
max.poll.records = 500
metadata.max.age.ms = 300000
metric.reporters = []
metrics.num.samples = 2
metrics.recording.level = INFO
metrics.sample.window.ms = 30000
partition.assignment.strategy = [class
org.apache.kafka.clients.consumer.RangeAssignor]
receive.buffer.bytes = 65536
reconnect.backoff.max.ms = 1000
reconnect.backoff.ms = 50
request.timeout.ms = 305000
retry.backoff.ms = 100
sasl.jaas.config = null
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
现象：
正常运行一段时间后，突然有一个partition的offset提交不上，但是还能正常消费处理，只是提交不了offset。这个问题不好复现，偶尔出现这个错误。
flink端异常信息如下：
2019-06-03 13:30:56,827 INFO
org.apache.kafka.clients.consumer.internals.AbstractCoordinator - Marking the
coordinator 1.1.1.1:9092 (id: 2147483030 rack: null) dead for group
flink-ad-realtime-useraction
2019-06-03 13:30:56,829 WARN
org.apache.kafka.clients.consumer.internals.ConsumerCoordinator - Auto-commit
of offsets {user_action-96=OffsetAndMetadata{offset=3208384842, metadata=''},
user_action-48=OffsetAndMetadata{offset=3204869414, metadata=''},
user_action-0=OffsetAndMetadata{offset=3208651598, metadata=''},
user_action-120=OffsetAndMetadata{offset=3208633960, metadata=''},
user_action-24=OffsetAndMetadata{offset=3205592887, metadata=''},
user_action-72=OffsetAndMetadata{offset=3209105919, metadata=''}} failed for
group flink-ad-realtime-useraction: Offset commit failed with a retriable
exception. You should retry committing offsets. The underlying error was: The
request timed out.
kafka broker端异常信息：
无
我们这边查了很久，不知道是什么原因导致offset提交失败的错误，还请帮忙看看。
