kafka参数配置详解

broker config

属性	默认值	描述
broker.id		必填参数，broker的惟一标识
log.dirs	/tmp/kafka-logs	Kafka数据存放的目录。能够指定多个目录，中间用逗号分隔，当新partition被建立的时会被存放到当前存放partition最少的目录。
port	9092	BrokerServer接受客户端链接的端口号
zookeeper.connect	null	Zookeeper的链接串，格式为：hostname1:port1,hostname2:port2,hostname3:port3。能够填一个或多个，为了提升可靠性，建议都填上。注意，此配置容许咱们指定一个zookeeper路径来存放此kafka集群的全部数据，为了与其余应用集群区分开，建议在此配置中指定本集群存放目录，格式为：hostname1:port1,hostname2:port2,hostname3:port3/chroot/path 。须要注意的是，消费者的参数要和此参数一致。
message.max.bytes	1000000	服务器能够接收到的最大的消息大小。注意此参数要和consumer的maximum.message.size大小一致，不然会由于生产者生产的消息太大致使消费者没法消费。
num.io.threads	8	服务器用来执行读写请求的IO线程数，此参数的数量至少要等于服务器上磁盘的数量。
queued.max.requests	500	I/O线程能够处理请求的队列大小，若实际请求数超过此大小，网络线程将中止接收新的请求。
socket.send.buffer.bytes	100 * 1024	The SO_SNDBUFF buffer the server prefers for socket connections.
socket.receive.buffer.bytes	100 * 1024	The SO_RCVBUFF buffer the server prefers for socket connections.
socket.request.max.bytes	100 * 1024 * 1024	服务器容许请求的最大值， 用来防止内存溢出，其值应该小于 Java heap size.
num.partitions	1	默认partition数量，若是topic在建立时没有指定partition数量，默认使用此值，建议改成5
log.segment.bytes	1024 * 1024 * 1024	Segment文件的大小，超过此值将会自动新建一个segment，此值能够被topic级别的参数覆盖。
log.roll.{ms,hours}	24 * 7 hours	新建segment文件的时间，此值能够被topic级别的参数覆盖。
log.retention.{ms,minutes,hours}	7 days	Kafka segment log的保存周期，保存周期超过此时间日志就会被删除。此参数能够被topic级别参数覆盖。数据量大时，建议减少此值。
log.retention.bytes	-1	每一个partition的最大容量，若数据量超过此值，partition数据将会被删除。注意这个参数控制的是每一个partition而不是topic。此参数能够被log级别参数覆盖。
log.retention.check.interval.ms	5 minutes	删除策略的检查周期
auto.create.topics.enable	true	自动建立topic参数，建议此值设置为false，严格控制topic管理，防止生产者错写topic。
default.replication.factor	1	默认副本数量，建议改成2。
replica.lag.time.max.ms	10000	在此窗口时间内没有收到follower的fetch请求，leader会将其从ISR(in-sync replicas)中移除。
replica.lag.max.messages	4000	若是replica节点落后leader节点此值大小的消息数量，leader节点就会将其从ISR中移除。
replica.socket.timeout.ms	30 * 1000	replica向leader发送请求的超时时间。
replica.socket.receive.buffer.bytes	64 * 1024	The socket receive buffer for network requests to the leader for replicating data.
replica.fetch.max.bytes	1024 * 1024	The number of byes of messages to attempt to fetch for each partition in the fetch requests the replicas send to the leader.
replica.fetch.wait.max.ms	500	The maximum amount of time to wait time for data to arrive on the leader in the fetch requests sent by the replicas to the leader.
num.replica.fetchers	1	Number of threads used to replicate messages from leaders. Increasing this value can increase the degree of I/O parallelism in the follower broker.
fetch.purgatory.purge.interval.requests	1000	The purge interval (in number of requests) of the fetch request purgatory.
zookeeper.session.timeout.ms	6000	ZooKeeper session 超时时间。若是在此时间内server没有向zookeeper发送心跳，zookeeper就会认为此节点已挂掉。 此值过低致使节点容易被标记死亡；若过高，.会致使太迟发现节点死亡。
zookeeper.connection.timeout.ms	6000	客户端链接zookeeper的超时时间。
zookeeper.sync.time.ms	2000	H ZK follower落后 ZK leader的时间。
controlled.shutdown.enable	true	容许broker shutdown。若是启用，broker在关闭本身以前会把它上面的全部leaders转移到其它brokers上，建议启用，增长集群稳定性。
auto.leader.rebalance.enable	true	If this is enabled the controller will automatically try to balance leadership for partitions among the brokers by periodically returning leadership to the “preferred” replica for each partition if it is available.
leader.imbalance.per.broker.percentage	10	The percentage of leader imbalance allowed per broker. The controller will rebalance leadership if this ratio goes above the configured value per broker.
leader.imbalance.check.interval.seconds	300	The frequency with which to check for leader imbalance.
offset.metadata.max.bytes	4096	The maximum amount of metadata to allow clients to save with their offsets.
connections.max.idle.ms	600000	Idle connections timeout: the server socket processor threads close the connections that idle more than this.
num.recovery.threads.per.data.dir	1	The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.
unclean.leader.election.enable	true	Indicates whether to enable replicas not in the ISR set to be elected as leader as a last resort, even though doing so may result in data loss.
delete.topic.enable	false	启用deletetopic参数，建议设置为true。
offsets.topic.num.partitions	50	The number of partitions for the offset commit topic. Since changing this after deployment is currently unsupported, we recommend using a higher setting for production (e.g., 100-200).
offsets.topic.retention.minutes	1440	Offsets that are older than this age will be marked for deletion. The actual purge will occur when the log cleaner compacts the offsets topic.
offsets.retention.check.interval.ms	600000	The frequency at which the offset manager checks for stale offsets.
offsets.topic.replication.factor	3	The replication factor for the offset commit topic. A higher setting (e.g., three or four) is recommended in order to ensure higher availability. If the offsets topic is created when fewer brokers than the replication factor then the offsets topic will be created with fewer replicas.
offsets.topic.segment.bytes	104857600	Segment size for the offsets topic. Since it uses a compacted topic, this should be kept relatively low in order to facilitate faster log compaction and loads.
offsets.load.buffer.size	5242880	An offset load occurs when a broker becomes the offset manager for a set of consumer groups (i.e., when it becomes a leader for an offsets topic partition). This setting corresponds to the batch size (in bytes) to use when reading from the offsets segments when loading offsets into the offset manager’s cache.
offsets.commit.required.acks	-1	The number of acknowledgements that are required before the offset commit can be accepted. This is similar to the producer’s acknowledgement setting. In general, the default should not be overridden.
offsets.commit.timeout.ms	5000	The offset commit will be delayed until this timeout or the required number of replicas have received the offset commit. This is similar to the producer request timeout.

 

producer config

属性	默认值	描述
metadata.broker.list		启动时producer查询brokers的列表，能够是集群中全部brokers的一个子集。注意，这个参数只是用来获取topic的元信息用，producer会从元信息中挑选合适的broker并与之创建socket链接。格式是：host1:port1,host2:port2。
request.required.acks	0	参见3.2节介绍
request.timeout.ms	10000	Broker等待ack的超时时间，若等待时间超过此值，会返回客户端错误信息。
producer.type	sync	同步异步模式。async表示异步，sync表示同步。若是设置成异步模式，能够容许生产者以batch的形式push数据，这样会极大的提升broker性能，推荐设置为异步。
serializer.class	kafka.serializer.DefaultEncoder	序列号类，.默认序列化成 byte[] 。
key.serializer.class		Key的序列化类，默认同上。
partitioner.class	kafka.producer.DefaultPartitioner	Partition类，默认对key进行hash。
compression.codec	none	指定producer消息的压缩格式，可选参数为： “none”, “gzip” and “snappy”。关于压缩参见4.1节
compressed.topics	null	启用压缩的topic名称。若上面参数选择了一个压缩格式，那么压缩仅对本参数指定的topic有效，若本参数为空，则对全部topic有效。
message.send.max.retries	3	Producer发送失败时重试次数。若网络出现问题，可能会致使不断重试。
retry.backoff.ms	100	Before each retry, the producer refreshes the metadata of relevant topics to see if a new leader has been elected. Since leader election takes a bit of time, this property specifies the amount of time that the producer waits before refreshing the metadata.
topic.metadata.refresh.interval.ms	600 * 1000	The producer generally refreshes the topic metadata from brokers when there is a failure (partition missing, leader not available…). It will also poll regularly (default: every 10min so 600000ms). If you set this to a negative value, metadata will only get refreshed on failure. If you set this to zero, the metadata will get refreshed after each message sent (not recommended). Important note: the refresh happen only AFTER the message is sent, so if the producer never sends a message the metadata is never refreshed
queue.buffering.max.ms	5000	启用异步模式时，producer缓存消息的时间。好比咱们设置成1000时，它会缓存1秒的数据再一次发送出去，这样能够极大的增长broker吞吐量，但也会形成时效性的下降。
queue.buffering.max.messages	10000	采用异步模式时producer buffer 队列里最大缓存的消息数量，若是超过这个数值，producer就会阻塞或者丢掉消息。
queue.enqueue.timeout.ms	-1	当达到上面参数值时producer阻塞等待的时间。若是值设置为0，buffer队列满时producer不会阻塞，消息直接被丢掉。若值设置为-1，producer会被阻塞，不会丢消息。
batch.num.messages	200	采用异步模式时，一个batch缓存的消息数量。达到这个数量值时producer才会发送消息。
send.buffer.bytes	100 * 1024	Socket write buffer size
client.id	“”	The client id is a user-specified string sent in each request to help trace calls. It should logically identify the application making the request.

 

consumer config

属性	默认值	描述
group.id		Consumer的组ID，相同goup.id的consumer属于同一个组。
zookeeper.connect		Consumer的zookeeper链接串，要和broker的配置一致。
consumer.id	null	若是不设置会自动生成。
socket.timeout.ms	30 * 1000	网络请求的socket超时时间。实际超时时间由max.fetch.wait + socket.timeout.ms 肯定。
socket.receive.buffer.bytes	64 * 1024	The socket receive buffer for network requests.
fetch.message.max.bytes	1024 * 1024	查询topic-partition时容许的最大消息大小。consumer会为每一个partition缓存此大小的消息到内存，所以，这个参数能够控制consumer的内存使用量。这个值应该至少比server容许的最大消息大小大，以避免producer发送的消息大于consumer容许的消息。
num.consumer.fetchers	1	The number fetcher threads used to fetch data.
auto.commit.enable	true	若是此值设置为true，consumer会周期性的把当前消费的offset值保存到zookeeper。当consumer失败重启以后将会使用此值做为新开始消费的值。
auto.commit.interval.ms	60 * 1000	Consumer提交offset值到zookeeper的周期。
queued.max.message.chunks	2	用来被consumer消费的message chunks 数量， 每一个chunk能够缓存fetch.message.max.bytes大小的数据量。
rebalance.max.retries	4	When a new consumer joins a consumer group the set of consumers attempt to “rebalance” the load to assign partitions to each consumer. If the set of consumers changes while this assignment is taking place the rebalance will fail and retry. This setting controls the maximum number of attempts before giving up.
fetch.min.bytes	1	The minimum amount of data the server should return for a fetch request. If insufficient data is available the request will wait for that much data to accumulate before answering the request.
fetch.wait.max.ms	100	The maximum amount of time the server will block before answering the fetch request if there isn’t sufficient data to immediately satisfy fetch.min.bytes.
rebalance.backoff.ms	2000	Backoff time between retries during rebalance.
refresh.leader.backoff.ms	200	Backoff time to wait before trying to determine the leader of a partition that has just lost its leader.
auto.offset.reset	largest	What to do when there is no initial offset in ZooKeeper or if an offset is out of range ;smallest : automatically reset the offset to the smallest offset; largest : automatically reset the offset to the largest offset;anything else: throw exception to the consumer
consumer.timeout.ms	-1	若在指定时间内没有消息消费，consumer将会抛出异常。
exclude.internal.topics	true	Whether messages from internal topics (such as offsets) should be exposed to the consumer.
zookeeper.session.timeout.ms	6000	ZooKeeper session timeout. If the consumer fails to heartbeat to ZooKeeper for this period of time it is considered dead and a rebalance will occur.
zookeeper.connection.timeout.ms	6000	The max time that the client waits while establishing a connection to zookeeper.
zookeeper.sync.time.ms	2000	How far a ZK follower can be behind a ZK leader