屬性

默認值

描述

broker.id

必填參數，broker的唯一標識

log.dirs

/tmp/kafka-logs

Kafka數據存放的目錄。可以指定多個目錄，中間用逗號分隔，當新partition被創建的時會被存放到當前存放partition最少的目錄。

port

9092

BrokerServer接受客戶端連接的端口號

zookeeper.connect

null

Zookeeper的連接串，格式為：hostname1:port1,hostname2:port2,hostname3:port3。可以填一個或多個，為了提高可靠性，建議都填上。注意，此配置允許我們指定一個zookeeper路徑來存放此kafka集群的所有數據，為了與其他應用集群區分開，建議在此配置中指定本集群存放目錄，格式為：hostname1:port1,hostname2:port2,hostname3:port3/chroot/path 。需要注意的是，消費者的參數要和此參數一致。

message.max.bytes

1000000

服務器可以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，否則會因為生產者生產的消息太大導致消費者無法消費。

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于服務器上磁盤的數量。

queued.max.requests

500

I/O線程可以處理請求的隊列大小，若實際請求數超過此大小，網絡線程將停止接收新的請求。

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

服務器允許請求的最大值， 用來防止內存溢出，其值應該小于 Java heap size.

num.partitions

1

默認partition數量，如果topic在創建時沒有指定partition數量，默認使用此值，建議改為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，此值可以被topic級別的參數覆蓋。

log.roll.{ms,hours}

24 * 7 hours

新建segment文件的時間，此值可以被topic級別的參數覆蓋。

log.retention.{ms,minutes,hours}

7 days

Kafka segment log的保存周期，保存周期超過此時間日志就會被刪除。此參數可以被topic級別參數覆蓋。數據量大時，建議減小此值。

log.retention.bytes

-1

每個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個partition而不是topic。此參數可以被log級別參數覆蓋。

log.retention.check.interval.ms

5 minutes

刪除策略的檢查周期

auto.create.topics.enable

true

自動創建topic參數，建議此值設置為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，建議改為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

如果replica節點落后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。如果在此時間內server沒有向zookeeper發送心跳，zookeeper就會認為此節點已掛掉。 此值太低導致節點容易被標記死亡；若太高，.會導致太遲發現節點死亡。

zookeeper.connection.timeout.ms

6000

客戶端連接zookeeper的超時時間。

zookeeper.sync.time.ms

2000

H ZK follower落后 ZK leader的時間。

controlled.shutdown.enable

true

允許broker shutdown。如果啟用，broker在關閉自己之前會把它上面的所有leaders轉移到其它brokers上，建議啟用，增加集群穩定性。

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

啟用deletetopic參數，建議設置為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.

屬性

默認值

描述

metadata.broker.list

啟動時producer查詢brokers的列表，可以是集群中所有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并與之建立socket連接。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。如果設置成異步模式，可以允許生產者以batch的形式push數據，這樣會極大的提高broker性能，推薦設置為異步。

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，可選參數為： “none”, “gzip” and “snappy”。關于壓縮參見4.1節

compressed.topics

null

啟用壓縮的topic名稱。若上面參數選擇了一個壓縮格式，那么壓縮僅對本參數指定的topic有效，若本參數為空，則對所有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，可能會導致不斷重試。

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

啟用異步模式時，producer緩存消息的時間。比如我們設置成1000時，它會緩存1秒的數據再一次發送出去，這樣可以極大的增加broker吞吐量，但也會造成時效性的降低。

queue.buffering.max.messages

10000

采用異步模式時producer buffer 隊列里最大緩存的消息數量，如果超過這個數值，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。如果值設置為0，buffer隊列滿時producer不會阻塞，消息直接被丟掉。若值設置為-1，producer會被阻塞，不會丟消息。

batch.num.messages

200

采用異步模式時，一個batch緩存的消息數量。達到這個數量值時producer才會發送消息。

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.

屬性

默認值

描述

group.id

Consumer的組ID，相同goup.id的consumer屬于同一個組。

zookeeper.connect

Consumer的zookeeper連接串，要和broker的配置一致。

consumer.id

null

如果不設置會自動生成。

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 確定。

socket.receive.buffer.bytes

64 * 1024

The socket receive buffer for network requests.

fetch.message.max.bytes

1024 * 1024

查詢topic-partition時允許的最大消息大小。consumer會為每個partition緩存此大小的消息到內存，因此，這個參數可以控制consumer的內存使用量。這個值應該至少比server允許的最大消息大小大，以免producer發送的消息大于consumer允許的消息。

num.consumer.fetchers

1

The number fetcher threads used to fetch data.

auto.commit.enable

true

如果此值設置為true，consumer會周期性的把當前消費的offset值保存到zookeeper。當consumer失敗重啟之后將會使用此值作為新開始消費的值。

auto.commit.interval.ms

60 * 1000

Consumer提交offset值到zookeeper的周期。

queued.max.message.chunks

2

用來被consumer消費的message chunks 數量， 每個chunk可以緩存fetch.message.max.bytes大小的數據量。

auto.commit.interval.ms

60 * 1000

Consumer提交offset值到zookeeper的周期。

queued.max.message.chunks

2

用來被consumer消費的message chunks 數量， 每個chunk可以緩存fetch.message.max.bytes大小的數據量。

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