brokerid

none

Each broker is uniquely identified by an id. This id serves as the brokers “name”, and allows the broker to be moved to a different host/port without confusing consumers.

enable.zookeeper

true

enable zookeeper registration in the server

log.flush.interval

500

Controls the number of messages accumulated in each topic (partition) before the data is flushed to disk and made available to consumers.

log.default.flush.scheduler.interval.ms

3000

Controls the interval at which logs are checked to see if they need to be flushed to disk. A background thread will run at a frequency specified by this parameter and will check each log to see if it has exceeded its flush.interval time, and if so it will flush it.

log.default.flush.interval.ms

log.default.flush.scheduler.interval.ms

Controls the maximum time that a message in any topic is kept in memory before flushed to disk. The value only makes sense if it’s a multiple of log.default.flush.scheduler.interval .ms

topic.flush.intervals.ms

none

Per-topic overrides for log.default.flush.interval.ms. Controls the maximum time that a message in selected topics is kept in memory before flushed to disk. The per-topic value only makes sense if it’s a multiple of log.default.flush.scheduler.interval.ms. E.g., topic1:1000,topic2:2000

log.retention.hours

168

Controls how long a log file is retained.

topic.log.retention.hours

none

Topic-specific retention time that overrides log.retention.hours, e.g., topic1:10,topic2:20

log.retention.size

-1

the maximum size of the log before deleting it. This controls how large a log is allowed to grow

log.cleanup.interval.mins

10

Controls how often the log cleaner checks logs eligible for deletion. A log file is eligible for deletion if it hasn’t been modified for log.retention.hours hours.

log.dir

none

Specifies the root directory in which all log data is kept.

log.file.size

110241024*1024

Controls the maximum size of a single log file.

log.roll.hours

24 * 7

The maximum time before a new log segment is rolled out

max.socket.request.bytes

104857600

the maximum number of bytes in a socket request

monitoring.period.secs

600

the interval in which to measure performance statistics

num.threads

Runtime.getRuntime().availableProcessors

Controls the number of worker threads in the broker to serve requests.

num.partitions

1

Specifies the default number of partitions per topic.

socket.send.buffer

102400

the SO_SNDBUFF buffer of the socket sever sockets

socket.receive.buffer

102400

the SO_RCVBUFF buffer of the socket sever sockets

topic.partition.count.map

none

Override parameter to control the number of partitions for selected topics. E.g., topic1:10,topic2:20

zk.connect

localhost:2182/kafka

Specifies the zookeeper connection string in the form hostname:port/chroot. Here the chroot is a base directory which is prepended to all path operations (this effectively namespaces all kafka znodes to allow sharing with other applications on the same zookeeper cluster)

zk.connectiontimeout.ms

6000

Specifies the max time that the client waits to establish a connection to zookeeper.

zk.sessiontimeout.ms

6000

The zookeeper session timeout.

zk.synctime.ms

2000

Max time for how far a ZK follower can be behind a ZK leader

groupid

groupid

is a string that uniquely identifies a set of consumers within the same consumer group.

socket.timeout.ms

30000

controls the socket timeout for network requests

socket.buffersize

64*1024

controls the socket receive buffer for network requests

fetch.size

300 * 1024

controls the number of bytes of messages to attempt to fetch in one request to the Kafka server

backoff.increment.ms

1000

This parameter avoids repeatedly polling a broker node which has no new data. We will backoff every time we get an empty set from the broker for this time period

queuedchunks.max

100

the high level consumer buffers the messages fetched from the server internally in blocking queues. This parameter controls the size of those queues

autocommit.enable

true

if set to true, the consumer periodically commits to zookeeper the latest consumed offset of each partition.

autocommit.interval.ms

10000

is the frequency that the consumed offsets are committed to zookeeper.

autooffset.reset

smallest

• smallest: automatically reset the offset to the smallest offset available on the broker.
• largest : automatically reset the offset to the largest offset available on the broker.
• anything else: throw an exception to the consumer.

consumer.timeout.ms

-1

By default, this value is -1 and a consumer blocks indefinitely if no new message is available for consumption. By setting the value to a positive integer, a timeout exception is thrown to the consumer if no message is available for consumption after the specified timeout value.

rebalance.retries.max

4

max number of retries during rebalance

mirror.topics.whitelist

""

Whitelist of topics for this mirror’s embedded consumer to consume. At most one of whitelist/blacklist may be specified.

mirror.topics.blacklist

""

Topics to skip mirroring. At most one of whitelist/blacklist may be specified

mirror.consumer.numthreads

4

The number of threads to be used per topic for the mirroring consumer, by default

serializer.class

kafka.serializer.DefaultEncoder. This is a no-op encoder. The serialization of data to Message should be handled outside the Producer

class that implements the kafka.serializer.Encoder<T> interface, used to encode data of type T into a Kafka message

partitioner.class

kafka.producer.DefaultPartitioner<T> - uses the partitioning strategy hash(key)%num_partitions. If key is null, then it picks a random partition.

class that implements the kafka.producer.Partitioner<K>, used to supply a custom partitioning strategy on the message key (of type K) that is specified through the ProducerData<K, T> object in the kafka.producer.Producer<T> send API

producer.type

sync

this parameter specifies whether the messages are sent asynchronously or not. Valid values are -

• async for asynchronous batching send through kafka.producer.AyncProducer
• sync for synchronous send through kafka.producer.SyncProducer

broker.list

null. Either this parameter or zk.connect needs to be specified by the user.

For bypassing zookeeper based auto partition discovery, use this config to pass in static broker and per-broker partition information. Format-brokerid1:host1:port1, brokerid2:host2:port2. If you use this option, the partitioner.class will be ignored and each producer request will be routed to a random broker partition.

zk.connect

null. Either this parameter or broker.partition.info needs to be specified by the user

For using the zookeeper based automatic broker discovery, use this config to pass in the zookeeper connection url to the zookeeper cluster where the Kafka brokers are registered.

buffer.size

102400

the socket buffer size, in bytes

connect.timeout.ms

5000

the maximum time spent by kafka.producer.SyncProducer trying to connect to the kafka broker. Once it elapses, the producer throws an ERROR and stops.

socket.timeout.ms

30000

The socket timeout in milliseconds

reconnect.interval

30000

the number of produce requests after which kafka.producer.SyncProducer tears down the socket connection to the broker and establishes it again; this and the following property are mainly used when the producer connects to the brokers through a VIP in a load balancer; they give the producer a chance to pick up the new broker periodically

reconnect.time.interval.ms

10 * 1000 * 1000

the amount of time after which kafka.producer.SyncProducer tears down the socket connection to the broker and establishes it again; negative reconnect time interval means disabling this time-based reconnect feature

max.message.size

1000000

the maximum number of bytes that the kafka.producer.SyncProducer can send as a single message payload

compression.codec

0 (No compression)

This parameter allows you to specify the compression codec for all data generated by this producer.

compressed.topics

null

This parameter allows you to set whether compression should be turned on for particular topics. If the compression codec is anything other than NoCompressionCodec, enable compression only for specified topics if any. If the list of compressed topics is empty, then enable the specified compression codec for all topics. If the compression codec is NoCompressionCodec, compression is disabled for all topics.

zk.read.num.retries

3

The producer using the zookeeper software load balancer maintains a ZK cache that gets updated by the zookeeper watcher listeners. During some events like a broker bounce, the producer ZK cache can get into an inconsistent state, for a small time period. In this time period, it could end up picking a broker partition that is unavailable. When this happens, the ZK cache needs to be updated. This parameter specifies the number of times the producer attempts to refresh this ZK cache.

Options for Asynchronous Producers (producer.type=async)

queue.time

5000

maximum time, in milliseconds, for buffering data on the producer queue. After it elapses, the buffered data in the producer queue is dispatched to the event.handler.

queue.size

10000

the maximum size of the blocking queue for buffering on the kafka.producer.AsyncProducer

batch.size

200

the number of messages batched at the producer, before being dispatched to the event.handler

event.handler

kafka.producer.async.EventHandler<T>

the class that implements kafka.producer.async.IEventHandler<T> used to dispatch a batch of produce requests, using an instance of kafka.producer.SyncProducer.

event.handler.props

null

the java.util.Properties() object used to initialize the custom event.handler through its init() API

callback.handler

null

the class that implements kafka.producer.async.CallbackHandler<T> used to inject callbacks at various stages of the kafka.producer.AsyncProducer pipeline.

callback.handler.props

null

the java.util.Properties() object used to initialize the custom callback.handler through its init() API