kafka參數配置詳解

broker config

屬性	默認值	描述
broker.id		必填參數，broker的惟一標識
log.dirs	/tmp/kafka-logs	Kafka數據存放的目錄。能夠指定多個目錄，中間用逗號分隔，當新partition被建立的時會被存放到當前存放partition最少的目錄。
port	9092	BrokerServer接受客戶端鏈接的端口號
zookeeper.connect	null	Zookeeper的鏈接串，格式爲：hostname1:port1,hostname2:port2,hostname3:port3。能夠填一個或多個，爲了提升可靠性，建議都填上。注意，此配置容許咱們指定一個zookeeper路徑來存放此kafka集羣的全部數據，爲了與其餘應用集羣區分開，建議在此配置中指定本集羣存放目錄，格式爲：hostname1:port1,hostname2:port2,hostname3:port3/chroot/path 。須要注意的是，消費者的參數要和此參數一致。
message.max.bytes	1000000	服務器能夠接收到的最大的消息大小。注意此參數要和consumer的maximum.message.size大小一致，不然會由於生產者生產的消息太大致使消費者沒法消費。
num.io.threads	8	服務器用來執行讀寫請求的IO線程數，此參數的數量至少要等於服務器上磁盤的數量。
queued.max.requests	500	I/O線程能夠處理請求的隊列大小，若實際請求數超過此大小，網絡線程將中止接收新的請求。
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	服務器容許請求的最大值， 用來防止內存溢出，其值應該小於 Java heap size.
num.partitions	1	默認partition數量，若是topic在建立時沒有指定partition數量，默認使用此值，建議改成5
log.segment.bytes	1024 * 1024 * 1024	Segment文件的大小，超過此值將會自動新建一個segment，此值能夠被topic級別的參數覆蓋。
log.roll.{ms,hours}	24 * 7 hours	新建segment文件的時間，此值能夠被topic級別的參數覆蓋。
log.retention.{ms,minutes,hours}	7 days	Kafka segment log的保存週期，保存週期超過此時間日誌就會被刪除。此參數能夠被topic級別參數覆蓋。數據量大時，建議減少此值。
log.retention.bytes	-1	每一個partition的最大容量，若數據量超過此值，partition數據將會被刪除。注意這個參數控制的是每一個partition而不是topic。此參數能夠被log級別參數覆蓋。
log.retention.check.interval.ms	5 minutes	刪除策略的檢查週期
auto.create.topics.enable	true	自動建立topic參數，建議此值設置爲false，嚴格控制topic管理，防止生產者錯寫topic。
default.replication.factor	1	默認副本數量，建議改成2。
replica.lag.time.max.ms	10000	在此窗口時間內沒有收到follower的fetch請求，leader會將其從ISR(in-sync replicas)中移除。
replica.lag.max.messages	4000	若是replica節點落後leader節點此值大小的消息數量，leader節點就會將其從ISR中移除。
replica.socket.timeout.ms	30 * 1000	replica向leader發送請求的超時時間。
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 超時時間。若是在此時間內server沒有向zookeeper發送心跳，zookeeper就會認爲此節點已掛掉。 此值過低致使節點容易被標記死亡；若過高，.會致使太遲發現節點死亡。
zookeeper.connection.timeout.ms	6000	客戶端鏈接zookeeper的超時時間。
zookeeper.sync.time.ms	2000	H ZK follower落後 ZK leader的時間。
controlled.shutdown.enable	true	容許broker shutdown。若是啓用，broker在關閉本身以前會把它上面的全部leaders轉移到其它brokers上，建議啓用，增長集羣穩定性。
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	啓用deletetopic參數，建議設置爲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

屬性	默認值	描述
metadata.broker.list		啓動時producer查詢brokers的列表，能夠是集羣中全部brokers的一個子集。注意，這個參數只是用來獲取topic的元信息用，producer會從元信息中挑選合適的broker並與之創建socket鏈接。格式是：host1:port1,host2:port2。
request.required.acks	0	參見3.2節介紹
request.timeout.ms	10000	Broker等待ack的超時時間，若等待時間超過此值，會返回客戶端錯誤信息。
producer.type	sync	同步異步模式。async表示異步，sync表示同步。若是設置成異步模式，能夠容許生產者以batch的形式push數據，這樣會極大的提升broker性能，推薦設置爲異步。
serializer.class	kafka.serializer.DefaultEncoder	序列號類，.默認序列化成 byte[] 。
key.serializer.class		Key的序列化類，默認同上。
partitioner.class	kafka.producer.DefaultPartitioner	Partition類，默認對key進行hash。
compression.codec	none	指定producer消息的壓縮格式，可選參數爲： 「none」, 「gzip」 and 「snappy」。關於壓縮參見4.1節
compressed.topics	null	啓用壓縮的topic名稱。若上面參數選擇了一個壓縮格式，那麼壓縮僅對本參數指定的topic有效，若本參數爲空，則對全部topic有效。
message.send.max.retries	3	Producer發送失敗時重試次數。若網絡出現問題，可能會致使不斷重試。
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	啓用異步模式時，producer緩存消息的時間。好比咱們設置成1000時，它會緩存1秒的數據再一次發送出去，這樣能夠極大的增長broker吞吐量，但也會形成時效性的下降。
queue.buffering.max.messages	10000	採用異步模式時producer buffer 隊列裏最大緩存的消息數量，若是超過這個數值，producer就會阻塞或者丟掉消息。
queue.enqueue.timeout.ms	-1	當達到上面參數值時producer阻塞等待的時間。若是值設置爲0，buffer隊列滿時producer不會阻塞，消息直接被丟掉。若值設置爲-1，producer會被阻塞，不會丟消息。
batch.num.messages	200	採用異步模式時，一個batch緩存的消息數量。達到這個數量值時producer纔會發送消息。
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

屬性	默認值	描述
group.id		Consumer的組ID，相同goup.id的consumer屬於同一個組。
zookeeper.connect		Consumer的zookeeper鏈接串，要和broker的配置一致。
consumer.id	null	若是不設置會自動生成。
socket.timeout.ms	30 * 1000	網絡請求的socket超時時間。實際超時時間由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	查詢topic-partition時容許的最大消息大小。consumer會爲每一個partition緩存此大小的消息到內存，所以，這個參數能夠控制consumer的內存使用量。這個值應該至少比server容許的最大消息大小大，以避免producer發送的消息大於consumer容許的消息。
num.consumer.fetchers	1	The number fetcher threads used to fetch data.
auto.commit.enable	true	若是此值設置爲true，consumer會週期性的把當前消費的offset值保存到zookeeper。當consumer失敗重啓以後將會使用此值做爲新開始消費的值。
auto.commit.interval.ms	60 * 1000	Consumer提交offset值到zookeeper的週期。
queued.max.message.chunks	2	用來被consumer消費的message chunks 數量， 每一個chunk能夠緩存fetch.message.max.bytes大小的數據量。
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	若在指定時間內沒有消息消費，consumer將會拋出異常。
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