Broker Configurations

This topic provides configuration parameters available for Confluent Platform. The parameters are organized by order of importance, ranked from high to low.

Name Description Type Default Valid Values Importance Dynamic Update Mode
zookeeper.connectSpecifies the ZooKeeper connection string in the form hostname:port where host and port are the host and port of a ZooKeeper server. To allow connecting through other ZooKeeper nodes when that ZooKeeper machine is down you can also specify multiple hosts in the form hostname1:port1,hostname2:port2,hostname3:port3. The server can also have a ZooKeeper chroot path as part of its ZooKeeper connection string which puts its data under some path in the global ZooKeeper namespace. For example to give a chroot path of /chroot/path you would give the connection string as hostname1:port1,hostname2:port2,hostname3:port3/chroot/path.stringhighread-only
advertised.host.nameDEPRECATED: only used when advertised.listeners or listeners are not set. Use advertised.listeners instead. Hostname to publish to ZooKeeper for clients to use. In IaaS environments, this may need to be different from the interface to which the broker binds. If this is not set, it will use the value for host.name if configured. Otherwise it will use the value returned from java.net.InetAddress.getCanonicalHostName().stringnullhighread-only
advertised.listenersListeners to publish to ZooKeeper for clients to use, if different than the listeners config property. In IaaS environments, this may need to be different from the interface to which the broker binds. If this is not set, the value for listeners will be used. Unlike listeners it is not valid to advertise the 0.0.0.0 meta-address.stringnullhighper-broker
advertised.portDEPRECATED: only used when advertised.listeners or listeners are not set. Use advertised.listeners instead. The port to publish to ZooKeeper for clients to use. In IaaS environments, this may need to be different from the port to which the broker binds. If this is not set, it will publish the same port that the broker binds to.intnullhighread-only
auto.create.topics.enableEnable auto creation of topic on the serverbooleantruehighread-only
auto.leader.rebalance.enableEnables auto leader balancing. A background thread checks and triggers leader balance if required at regular intervalsbooleantruehighread-only
background.threadsThe number of threads to use for various background processing tasksint10[1,...]highcluster-wide
broker.idThe broker id for this server. If unset, a unique broker id will be generated.To avoid conflicts between zookeeper generated broker id's and user configured broker id's, generated broker ids start from reserved.broker.max.id + 1.int-1highread-only
compression.typeSpecify the final compression type for a given topic. This configuration accepts the standard compression codecs ('gzip', 'snappy', 'lz4', 'zstd'). It additionally accepts 'uncompressed' which is equivalent to no compression; and 'producer' which means retain the original compression codec set by the producer.stringproducerhighcluster-wide
control.plane.listener.nameName of listener used for communication between controller and brokers. Broker will use the control.plane.listener.name to locate the endpoint in listeners list, to listen for connections from the controller. For example, if a broker's config is : listeners = INTERNAL://192.1.1.8:9092, EXTERNAL://10.1.1.5:9093, CONTROLLER://192.1.1.8:9094 listener.security.protocol.map = INTERNAL:PLAINTEXT, EXTERNAL:SSL, CONTROLLER:SSL control.plane.listener.name = CONTROLLER On startup, the broker will start listening on "192.1.1.8:9094" with security protocol "SSL". On controller side, when it discovers a broker's published endpoints through zookeeper, it will use the control.plane.listener.name to find the endpoint, which it will use to establish connection to the broker. For example, if the broker's published endpoints on zookeeper are : "endpoints" : ["INTERNAL://broker1.example.com:9092","EXTERNAL://broker1.example.com:9093","CONTROLLER://broker1.example.com:9094"] and the controller's config is : listener.security.protocol.map = INTERNAL:PLAINTEXT, EXTERNAL:SSL, CONTROLLER:SSL control.plane.listener.name = CONTROLLER then controller will use "broker1.example.com:9094" with security protocol "SSL" to connect to the broker. If not explicitly configured, the default value will be null and there will be no dedicated endpoints for controller connections.stringnullhighread-only
delete.topic.enableEnables delete topic. Delete topic through the admin tool will have no effect if this config is turned offbooleantruehighread-only
host.nameDEPRECATED: only used when listeners is not set. Use listeners instead. hostname of broker. If this is set, it will only bind to this address. If this is not set, it will bind to all interfacesstring""highread-only
leader.imbalance.check.interval.secondsThe frequency with which the partition rebalance check is triggered by the controllerlong300highread-only
leader.imbalance.per.broker.percentageThe ratio of leader imbalance allowed per broker. The controller would trigger a leader balance if it goes above this value per broker. The value is specified in percentage.int10highread-only
listenersListener List - Comma-separated list of URIs we will listen on and the listener names. If the listener name is not a security protocol, listener.security.protocol.map must also be set. Specify hostname as 0.0.0.0 to bind to all interfaces. Leave hostname empty to bind to default interface. Examples of legal listener lists: PLAINTEXT://myhost:9092,SSL://:9091 CLIENT://0.0.0.0:9092,REPLICATION://localhost:9093 stringnullhighper-broker
log.dirThe directory in which the log data is kept (supplemental for log.dirs property)string/tmp/kafka-logshighread-only
log.dirsThe directories in which the log data is kept. If not set, the value in log.dir is usedstringnullhighread-only
log.flush.interval.messagesThe number of messages accumulated on a log partition before messages are flushed to disk long9223372036854775807[1,...]highcluster-wide
log.flush.interval.msThe maximum time in ms that a message in any topic is kept in memory before flushed to disk. If not set, the value in log.flush.scheduler.interval.ms is usedlongnullhighcluster-wide
log.flush.offset.checkpoint.interval.msThe frequency with which we update the persistent record of the last flush which acts as the log recovery pointint60000[0,...]highread-only
log.flush.scheduler.interval.msThe frequency in ms that the log flusher checks whether any log needs to be flushed to disklong9223372036854775807highread-only
log.flush.start.offset.checkpoint.interval.msThe frequency with which we update the persistent record of log start offsetint60000[0,...]highread-only
log.retention.bytesThe maximum size of the log before deleting itlong-1highcluster-wide
log.retention.hoursThe number of hours to keep a log file before deleting it (in hours), tertiary to log.retention.ms propertyint168highread-only
log.retention.minutesThe number of minutes to keep a log file before deleting it (in minutes), secondary to log.retention.ms property. If not set, the value in log.retention.hours is usedintnullhighread-only
log.retention.msThe number of milliseconds to keep a log file before deleting it (in milliseconds), If not set, the value in log.retention.minutes is usedlongnullhighcluster-wide
log.roll.hoursThe maximum time before a new log segment is rolled out (in hours), secondary to log.roll.ms propertyint168[1,...]highread-only
log.roll.jitter.hoursThe maximum jitter to subtract from logRollTimeMillis (in hours), secondary to log.roll.jitter.ms propertyint0[0,...]highread-only
log.roll.jitter.msThe maximum jitter to subtract from logRollTimeMillis (in milliseconds). If not set, the value in log.roll.jitter.hours is usedlongnullhighcluster-wide
log.roll.msThe maximum time before a new log segment is rolled out (in milliseconds). If not set, the value in log.roll.hours is usedlongnullhighcluster-wide
log.segment.bytesThe maximum size of a single log fileint1073741824[14,...]highcluster-wide
log.segment.delete.delay.msThe amount of time to wait before deleting a file from the filesystemlong60000[0,...]highcluster-wide
message.max.bytes

The largest record batch size allowed by Kafka. If this is increased and there are consumers older than 0.10.2, the consumers' fetch size must also be increased so that the they can fetch record batches this large.

In the latest message format version, records are always grouped into batches for efficiency. In previous message format versions, uncompressed records are not grouped into batches and this limit only applies to a single record in that case.

This can be set per topic with the topic level max.message.bytes config.

int1000012[0,...]highcluster-wide
min.insync.replicasWhen a producer sets acks to "all" (or "-1"), min.insync.replicas specifies the minimum number of replicas that must acknowledge a write for the write to be considered successful. If this minimum cannot be met, then the producer will raise an exception (either NotEnoughReplicas or NotEnoughReplicasAfterAppend).
When used together, min.insync.replicas and acks allow you to enforce greater durability guarantees. A typical scenario would be to create a topic with a replication factor of 3, set min.insync.replicas to 2, and produce with acks of "all". This will ensure that the producer raises an exception if a majority of replicas do not receive a write.
int1[1,...]highcluster-wide
num.io.threadsThe number of threads that the server uses for processing requests, which may include disk I/Oint8[1,...]highcluster-wide
num.network.threadsThe number of threads that the server uses for receiving requests from the network and sending responses to the networkint3[1,...]highcluster-wide
num.recovery.threads.per.data.dirThe number of threads per data directory to be used for log recovery at startup and flushing at shutdownint1[1,...]highcluster-wide
num.replica.alter.log.dirs.threadsThe number of threads that can move replicas between log directories, which may include disk I/Ointnullhighread-only
num.replica.fetchersNumber of fetcher threads used to replicate messages from a source broker. Increasing this value can increase the degree of I/O parallelism in the follower broker.int1highcluster-wide
offset.metadata.max.bytesThe maximum size for a metadata entry associated with an offset commitint4096highread-only
offsets.commit.required.acksThe required acks before the commit can be accepted. In general, the default (-1) should not be overriddenshort-1highread-only
offsets.commit.timeout.msOffset commit will be delayed until all replicas for the offsets topic receive the commit or this timeout is reached. This is similar to the producer request timeout.int5000[1,...]highread-only
offsets.load.buffer.sizeBatch size for reading from the offsets segments when loading offsets into the cache (soft-limit, overridden if records are too large).int5242880[1,...]highread-only
offsets.retention.check.interval.msFrequency at which to check for stale offsetslong600000[1,...]highread-only
offsets.retention.minutesAfter a consumer group loses all its consumers (i.e. becomes empty) its offsets will be kept for this retention period before getting discarded. For standalone consumers (using manual assignment), offsets will be expired after the time of last commit plus this retention period.int10080[1,...]highread-only
offsets.topic.compression.codecCompression codec for the offsets topic - compression may be used to achieve "atomic" commitsint0highread-only
offsets.topic.num.partitionsThe number of partitions for the offset commit topic (should not change after deployment)int50[1,...]highread-only
offsets.topic.replication.factorThe replication factor for the offsets topic (set higher to ensure availability). Internal topic creation will fail until the cluster size meets this replication factor requirement.short3[1,...]highread-only
offsets.topic.segment.bytesThe offsets topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loadsint104857600[1,...]highread-only
portDEPRECATED: only used when listeners is not set. Use listeners instead. the port to listen and accept connections onint9092highread-only
queued.max.requestsThe number of queued requests allowed for data-plane, before blocking the network threadsint500[1,...]highread-only
quota.consumer.defaultDEPRECATED: Used only when dynamic default quotas are not configured for or in Zookeeper. Any consumer distinguished by clientId/consumer group will get throttled if it fetches more bytes than this value per-secondlong9223372036854775807[1,...]highread-only
quota.producer.defaultDEPRECATED: Used only when dynamic default quotas are not configured for , or in Zookeeper. Any producer distinguished by clientId will get throttled if it produces more bytes than this value per-secondlong9223372036854775807[1,...]highread-only
replica.fetch.min.bytesMinimum bytes expected for each fetch response. If not enough bytes, wait up to replicaMaxWaitTimeMsint1highread-only
replica.fetch.wait.max.msmax wait time for each fetcher request issued by follower replicas. This value should always be less than the replica.lag.time.max.ms at all times to prevent frequent shrinking of ISR for low throughput topicsint500highread-only
replica.high.watermark.checkpoint.interval.msThe frequency with which the high watermark is saved out to disklong5000highread-only
replica.lag.time.max.msIf a follower hasn't sent any fetch requests or hasn't consumed up to the leaders log end offset for at least this time, the leader will remove the follower from isrlong10000highread-only
replica.socket.receive.buffer.bytesThe socket receive buffer for network requestsint65536highread-only
replica.socket.timeout.msThe socket timeout for network requests. Its value should be at least replica.fetch.wait.max.msint30000highread-only
request.timeout.msThe configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.int30000highread-only
socket.receive.buffer.bytesThe SO_RCVBUF buffer of the socket sever sockets. If the value is -1, the OS default will be used.int102400highread-only
socket.request.max.bytesThe maximum number of bytes in a socket requestint104857600[1,...]highread-only
socket.send.buffer.bytesThe SO_SNDBUF buffer of the socket sever sockets. If the value is -1, the OS default will be used.int102400highread-only
transaction.max.timeout.msThe maximum allowed timeout for transactions. If a client’s requested transaction time exceed this, then the broker will return an error in InitProducerIdRequest. This prevents a client from too large of a timeout, which can stall consumers reading from topics included in the transaction.int900000[1,...]highread-only
transaction.state.log.load.buffer.sizeBatch size for reading from the transaction log segments when loading producer ids and transactions into the cache (soft-limit, overridden if records are too large).int5242880[1,...]highread-only
transaction.state.log.min.isrOverridden min.insync.replicas config for the transaction topic.int2[1,...]highread-only
transaction.state.log.num.partitionsThe number of partitions for the transaction topic (should not change after deployment).int50[1,...]highread-only
transaction.state.log.replication.factorThe replication factor for the transaction topic (set higher to ensure availability). Internal topic creation will fail until the cluster size meets this replication factor requirement.short3[1,...]highread-only
transaction.state.log.segment.bytesThe transaction topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loadsint104857600[1,...]highread-only
transactional.id.expiration.msThe maximum amount of time in ms that the transaction coordinator will wait before proactively expire a producer's transactional id without receiving any transaction status updates from it.int604800000[1,...]highread-only
unclean.leader.election.enableIndicates 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 lossbooleanfalsehighcluster-wide
zookeeper.connection.timeout.msThe max time that the client waits to establish a connection to zookeeper. If not set, the value in zookeeper.session.timeout.ms is usedintnullhighread-only
zookeeper.max.in.flight.requestsThe maximum number of unacknowledged requests the client will send to Zookeeper before blocking.int10[1,...]highread-only
zookeeper.session.timeout.msZookeeper session timeoutint6000highread-only
zookeeper.set.aclSet client to use secure ACLsbooleanfalsehighread-only
broker.id.generation.enableEnable automatic broker id generation on the server. When enabled the value configured for reserved.broker.max.id should be reviewed.booleantruemediumread-only
broker.rackRack of the broker. This will be used in rack aware replication assignment for fault tolerance. Examples: `RACK1`, `us-east-1d`stringnullmediumread-only
connections.max.idle.msIdle connections timeout: the server socket processor threads close the connections that idle more than thislong600000mediumread-only
connections.max.reauth.msWhen explicitly set to a positive number (the default is 0, not a positive number), a session lifetime that will not exceed the configured value will be communicated to v2.2.0 or later clients when they authenticate. The broker will disconnect any such connection that is not re-authenticated within the session lifetime and that is then subsequently used for any purpose other than re-authentication. Configuration names can optionally be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.oauthbearer.connections.max.reauth.ms=3600000long0mediumread-only
controlled.shutdown.enableEnable controlled shutdown of the serverbooleantruemediumread-only
controlled.shutdown.max.retriesControlled shutdown can fail for multiple reasons. This determines the number of retries when such failure happensint3mediumread-only
controlled.shutdown.retry.backoff.msBefore each retry, the system needs time to recover from the state that caused the previous failure (Controller fail over, replica lag etc). This config determines the amount of time to wait before retrying.long5000mediumread-only
controller.socket.timeout.msThe socket timeout for controller-to-broker channelsint30000mediumread-only
default.replication.factordefault replication factors for automatically created topicsint1mediumread-only
delegation.token.expiry.time.msThe token validity time in miliseconds before the token needs to be renewed. Default value 1 day.long86400000[1,...]mediumread-only
delegation.token.master.keyPrimary/secret key to generate and verify delegation tokens. Same key must be configured across all the brokers. If the key is not set or set to empty string, brokers will disable the delegation token support.passwordnullmediumread-only
delegation.token.max.lifetime.msThe token has a maximum lifetime beyond which it cannot be renewed anymore. Default value 7 days.long604800000[1,...]mediumread-only
delete.records.purgatory.purge.interval.requestsThe purge interval (in number of requests) of the delete records request purgatoryint1mediumread-only
fetch.purgatory.purge.interval.requestsThe purge interval (in number of requests) of the fetch request purgatoryint1000mediumread-only
group.initial.rebalance.delay.msThe amount of time the group coordinator will wait for more consumers to join a new group before performing the first rebalance. A longer delay means potentially fewer rebalances, but increases the time until processing begins.int3000mediumread-only
group.max.session.timeout.msThe maximum allowed session timeout for registered consumers. Longer timeouts give consumers more time to process messages in between heartbeats at the cost of a longer time to detect failures.int300000mediumread-only
group.max.sizeThe maximum number of consumers that a single consumer group can accommodate.int2147483647[1,...]mediumread-only
group.min.session.timeout.msThe minimum allowed session timeout for registered consumers. Shorter timeouts result in quicker failure detection at the cost of more frequent consumer heartbeating, which can overwhelm broker resources.int6000mediumread-only
inter.broker.listener.nameName of listener used for communication between brokers. If this is unset, the listener name is defined by security.inter.broker.protocol. It is an error to set this and security.inter.broker.protocol properties at the same time.stringnullmediumread-only
inter.broker.protocol.versionSpecify which version of the inter-broker protocol will be used. This is typically bumped after all brokers were upgraded to a new version. Example of some valid values are: 0.8.0, 0.8.1, 0.8.1.1, 0.8.2, 0.8.2.0, 0.8.2.1, 0.9.0.0, 0.9.0.1 Check ApiVersion for the full list.string2.2-IV1[0.8.0, 0.8.1, 0.8.2, 0.9.0, 0.10.0-IV0, 0.10.0-IV1, 0.10.1-IV0, 0.10.1-IV1, 0.10.1-IV2, 0.10.2-IV0, 0.11.0-IV0, 0.11.0-IV1, 0.11.0-IV2, 1.0-IV0, 1.1-IV0, 2.0-IV0, 2.0-IV1, 2.1-IV0, 2.1-IV1, 2.1-IV2, 2.2-IV0, 2.2-IV1]mediumread-only
log.cleaner.backoff.msThe amount of time to sleep when there are no logs to cleanlong15000[0,...]mediumcluster-wide
log.cleaner.dedupe.buffer.sizeThe total memory used for log deduplication across all cleaner threadslong134217728mediumcluster-wide
log.cleaner.delete.retention.msHow long are delete records retained?long86400000mediumcluster-wide
log.cleaner.enableEnable the log cleaner process to run on the server. Should be enabled if using any topics with a cleanup.policy=compact including the internal offsets topic. If disabled those topics will not be compacted and continually grow in size.booleantruemediumread-only
log.cleaner.io.buffer.load.factorLog cleaner dedupe buffer load factor. The percentage full the dedupe buffer can become. A higher value will allow more log to be cleaned at once but will lead to more hash collisionsdouble0.9mediumcluster-wide
log.cleaner.io.buffer.sizeThe total memory used for log cleaner I/O buffers across all cleaner threadsint524288[0,...]mediumcluster-wide
log.cleaner.io.max.bytes.per.secondThe log cleaner will be throttled so that the sum of its read and write i/o will be less than this value on averagedouble1.7976931348623157E308mediumcluster-wide
log.cleaner.min.cleanable.ratioThe minimum ratio of dirty log to total log for a log to eligible for cleaningdouble0.5mediumcluster-wide
log.cleaner.min.compaction.lag.msThe minimum time a message will remain uncompacted in the log. Only applicable for logs that are being compacted.long0mediumcluster-wide
log.cleaner.threadsThe number of background threads to use for log cleaningint1[0,...]mediumcluster-wide
log.cleanup.policyThe default cleanup policy for segments beyond the retention window. A comma separated list of valid policies. Valid policies are: "delete" and "compact"listdelete[compact, delete]mediumcluster-wide
log.index.interval.bytesThe interval with which we add an entry to the offset indexint4096[0,...]mediumcluster-wide
log.index.size.max.bytesThe maximum size in bytes of the offset indexint10485760[4,...]mediumcluster-wide
log.message.format.versionSpecify the message format version the broker will use to append messages to the logs. The value should be a valid ApiVersion. Some examples are: 0.8.2, 0.9.0.0, 0.10.0, check ApiVersion for more details. By setting a particular message format version, the user is certifying that all the existing messages on disk are smaller or equal than the specified version. Setting this value incorrectly will cause consumers with older versions to break as they will receive messages with a format that they don't understand.string2.2-IV1[0.8.0, 0.8.1, 0.8.2, 0.9.0, 0.10.0-IV0, 0.10.0-IV1, 0.10.1-IV0, 0.10.1-IV1, 0.10.1-IV2, 0.10.2-IV0, 0.11.0-IV0, 0.11.0-IV1, 0.11.0-IV2, 1.0-IV0, 1.1-IV0, 2.0-IV0, 2.0-IV1, 2.1-IV0, 2.1-IV1, 2.1-IV2, 2.2-IV0, 2.2-IV1]mediumread-only
log.message.timestamp.difference.max.msThe maximum difference allowed between the timestamp when a broker receives a message and the timestamp specified in the message. If log.message.timestamp.type=CreateTime, a message will be rejected if the difference in timestamp exceeds this threshold. This configuration is ignored if log.message.timestamp.type=LogAppendTime.The maximum timestamp difference allowed should be no greater than log.retention.ms to avoid unnecessarily frequent log rolling.long9223372036854775807mediumcluster-wide
log.message.timestamp.typeDefine whether the timestamp in the message is message create time or log append time. The value should be either `CreateTime` or `LogAppendTime`stringCreateTime[CreateTime, LogAppendTime]mediumcluster-wide
log.preallocateShould pre allocate file when create new segment? If you are using Kafka on Windows, you probably need to set it to true.booleanfalsemediumcluster-wide
log.retention.check.interval.msThe frequency in milliseconds that the log cleaner checks whether any log is eligible for deletionlong300000[1,...]mediumread-only
max.connections.per.ipThe maximum number of connections we allow from each ip address. This can be set to 0 if there are overrides configured using max.connections.per.ip.overrides propertyint2147483647[0,...]mediumcluster-wide
max.connections.per.ip.overridesA comma-separated list of per-ip or hostname overrides to the default maximum number of connections. An example value is "hostName:100,127.0.0.1:200"string""mediumcluster-wide
max.incremental.fetch.session.cache.slotsThe maximum number of incremental fetch sessions that we will maintain.int1000[0,...]mediumread-only
num.partitionsThe default number of log partitions per topicint1[1,...]mediumread-only
password.encoder.old.secretThe old secret that was used for encoding dynamically configured passwords. This is required only when the secret is updated. If specified, all dynamically encoded passwords are decoded using this old secret and re-encoded using password.encoder.secret when broker starts up.passwordnullmediumread-only
password.encoder.secretThe secret used for encoding dynamically configured passwords for this broker.passwordnullmediumread-only
principal.builder.classThe fully qualified name of a class that implements the KafkaPrincipalBuilder interface, which is used to build the KafkaPrincipal object used during authorization. This config also supports the deprecated PrincipalBuilder interface which was previously used for client authentication over SSL. If no principal builder is defined, the default behavior depends on the security protocol in use. For SSL authentication, the principal will be derived using the rules defined by ssl.principal.mapping.rules applied on the distinguished name from the client certificate if one is provided; otherwise, if client authentication is not required, the principal name will be ANONYMOUS. For SASL authentication, the principal will be derived using the rules defined by sasl.kerberos.principal.to.local.rules if GSSAPI is in use, and the SASL authentication ID for other mechanisms. For PLAINTEXT, the principal will be ANONYMOUS.classnullmediumper-broker
producer.purgatory.purge.interval.requestsThe purge interval (in number of requests) of the producer request purgatoryint1000mediumread-only
queued.max.request.bytesThe number of queued bytes allowed before no more requests are readlong-1mediumread-only
replica.fetch.backoff.msThe amount of time to sleep when fetch partition error occurs.int1000[0,...]mediumread-only
replica.fetch.max.bytesThe number of bytes of messages to attempt to fetch for each partition. This is not an absolute maximum, if the first record batch in the first non-empty partition of the fetch is larger than this value, the record batch will still be returned to ensure that progress can be made. The maximum record batch size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config).int1048576[0,...]mediumread-only
replica.fetch.response.max.bytesMaximum bytes expected for the entire fetch response. Records are fetched in batches, and if the first record batch in the first non-empty partition of the fetch is larger than this value, the record batch will still be returned to ensure that progress can be made. As such, this is not an absolute maximum. The maximum record batch size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config).int10485760[0,...]mediumread-only
reserved.broker.max.idMax number that can be used for a broker.idint1000[0,...]mediumread-only
sasl.client.callback.handler.classThe fully qualified name of a SASL client callback handler class that implements the AuthenticateCallbackHandler interface.classnullmediumread-only
sasl.enabled.mechanismsThe list of SASL mechanisms enabled in the Kafka server. The list may contain any mechanism for which a security provider is available. Only GSSAPI is enabled by default.listGSSAPImediumper-broker
sasl.jaas.configJAAS login context parameters for SASL connections in the format used by JAAS configuration files. JAAS configuration file format is described here. The format for the value is: 'loginModuleClass controlFlag (optionName=optionValue)*;'. For brokers, the config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.jaas.config=com.example.ScramLoginModule required;passwordnullmediumper-broker
sasl.kerberos.kinit.cmdKerberos kinit command path.string/usr/bin/kinitmediumper-broker
sasl.kerberos.min.time.before.reloginLogin thread sleep time between refresh attempts.long60000mediumper-broker
sasl.kerberos.principal.to.local.rulesA list of rules for mapping from principal names to short names (typically operating system usernames). The rules are evaluated in order and the first rule that matches a principal name is used to map it to a short name. Any later rules in the list are ignored. By default, principal names of the form {username}/{hostname}@{REALM} are mapped to {username}. For more details on the format please see security authorization and acls. Note that this configuration is ignored if an extension of KafkaPrincipalBuilder is provided by the principal.builder.class configuration.listDEFAULTmediumper-broker
sasl.kerberos.service.nameThe Kerberos principal name that Kafka runs as. This can be defined either in Kafka's JAAS config or in Kafka's config.stringnullmediumper-broker
sasl.kerberos.ticket.renew.jitterPercentage of random jitter added to the renewal time.double0.05mediumper-broker
sasl.kerberos.ticket.renew.window.factorLogin thread will sleep until the specified window factor of time from last refresh to ticket's expiry has been reached, at which time it will try to renew the ticket.double0.8mediumper-broker
sasl.login.callback.handler.classThe fully qualified name of a SASL login callback handler class that implements the AuthenticateCallbackHandler interface. For brokers, login callback handler config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.callback.handler.class=com.example.CustomScramLoginCallbackHandlerclassnullmediumread-only
sasl.login.classThe fully qualified name of a class that implements the Login interface. For brokers, login config must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.scram-sha-256.sasl.login.class=com.example.CustomScramLoginclassnullmediumread-only
sasl.login.refresh.buffer.secondsThe amount of buffer time before credential expiration to maintain when refreshing a credential, in seconds. If a refresh would otherwise occur closer to expiration than the number of buffer seconds then the refresh will be moved up to maintain as much of the buffer time as possible. Legal values are between 0 and 3600 (1 hour); a default value of 300 (5 minutes) is used if no value is specified. This value and sasl.login.refresh.min.period.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.short300mediumper-broker
sasl.login.refresh.min.period.secondsThe desired minimum time for the login refresh thread to wait before refreshing a credential, in seconds. Legal values are between 0 and 900 (15 minutes); a default value of 60 (1 minute) is used if no value is specified. This value and sasl.login.refresh.buffer.seconds are both ignored if their sum exceeds the remaining lifetime of a credential. Currently applies only to OAUTHBEARER.short60mediumper-broker
sasl.login.refresh.window.factorLogin refresh thread will sleep until the specified window factor relative to the credential's lifetime has been reached, at which time it will try to refresh the credential. Legal values are between 0.5 (50%) and 1.0 (100%) inclusive; a default value of 0.8 (80%) is used if no value is specified. Currently applies only to OAUTHBEARER.double0.8mediumper-broker
sasl.login.refresh.window.jitterThe maximum amount of random jitter relative to the credential's lifetime that is added to the login refresh thread's sleep time. Legal values are between 0 and 0.25 (25%) inclusive; a default value of 0.05 (5%) is used if no value is specified. Currently applies only to OAUTHBEARER.double0.05mediumper-broker
sasl.mechanism.inter.broker.protocolSASL mechanism used for inter-broker communication. Default is GSSAPI.stringGSSAPImediumper-broker
sasl.server.callback.handler.classThe fully qualified name of a SASL server callback handler class that implements the AuthenticateCallbackHandler interface. Server callback handlers must be prefixed with listener prefix and SASL mechanism name in lower-case. For example, listener.name.sasl_ssl.plain.sasl.server.callback.handler.class=com.example.CustomPlainCallbackHandler.classnullmediumread-only
security.inter.broker.protocolSecurity protocol used to communicate between brokers. Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL. It is an error to set this and inter.broker.listener.name properties at the same time.stringPLAINTEXTmediumread-only
ssl.cipher.suitesA list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol. By default all the available cipher suites are supported.list""mediumper-broker
ssl.client.authConfigures kafka broker to request client authentication. The following settings are common:
  • ssl.client.auth=required If set to required client authentication is required.
  • ssl.client.auth=requested This means client authentication is optional. unlike requested , if this option is set client can choose not to provide authentication information about itself
  • ssl.client.auth=none This means client authentication is not needed.
stringnone[required, requested, none]mediumper-broker
ssl.enabled.protocolsThe list of protocols enabled for SSL connections.listTLSv1.2,TLSv1.1,TLSv1mediumper-broker
ssl.key.passwordThe password of the private key in the key store file. This is optional for client.passwordnullmediumper-broker
ssl.keymanager.algorithmThe algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.stringSunX509mediumper-broker
ssl.keystore.locationThe location of the key store file. This is optional for client and can be used for two-way authentication for client.stringnullmediumper-broker
ssl.keystore.passwordThe store password for the key store file. This is optional for client and only needed if ssl.keystore.location is configured. passwordnullmediumper-broker
ssl.keystore.typeThe file format of the key store file. This is optional for client.stringJKSmediumper-broker
ssl.protocolThe SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.stringTLSmediumper-broker
ssl.providerThe name of the security provider used for SSL connections. Default value is the default security provider of the JVM.stringnullmediumper-broker
ssl.trustmanager.algorithmThe algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.stringPKIXmediumper-broker
ssl.truststore.locationThe location of the trust store file. stringnullmediumper-broker
ssl.truststore.passwordThe password for the trust store file. If a password is not set access to the truststore is still available, but integrity checking is disabled.passwordnullmediumper-broker
ssl.truststore.typeThe file format of the trust store file.stringJKSmediumper-broker
alter.config.policy.class.nameThe alter configs policy class that should be used for validation. The class should implement the org.apache.kafka.server.policy.AlterConfigPolicy interface.classnulllowread-only
alter.log.dirs.replication.quota.window.numThe number of samples to retain in memory for alter log dirs replication quotasint11[1,...]lowread-only
alter.log.dirs.replication.quota.window.size.secondsThe time span of each sample for alter log dirs replication quotasint1[1,...]lowread-only
authorizer.class.nameThe authorizer class that should be used for authorizationstring""lowread-only
client.quota.callback.classThe fully qualified name of a class that implements the ClientQuotaCallback interface, which is used to determine quota limits applied to client requests. By default, , or quotas stored in ZooKeeper are applied. For any given request, the most specific quota that matches the user principal of the session and the client-id of the request is applied.classnulllowread-only
connection.failed.authentication.delay.msConnection close delay on failed authentication: this is the time (in milliseconds) by which connection close will be delayed on authentication failure. This must be configured to be less than connections.max.idle.ms to prevent connection timeout.int100[0,...]lowread-only
create.topic.policy.class.nameThe create topic policy class that should be used for validation. The class should implement the org.apache.kafka.server.policy.CreateTopicPolicy interface.classnulllowread-only
delegation.token.expiry.check.interval.msScan interval to remove expired delegation tokens.long3600000[1,...]lowread-only
kafka.metrics.polling.interval.secsThe metrics polling interval (in seconds) which can be used in kafka.metrics.reporters implementations.int10[1,...]lowread-only
kafka.metrics.reportersA list of classes to use as Yammer metrics custom reporters. The reporters should implement kafka.metrics.KafkaMetricsReporter trait. If a client wants to expose JMX operations on a custom reporter, the custom reporter needs to additionally implement an MBean trait that extends kafka.metrics.KafkaMetricsReporterMBean trait so that the registered MBean is compliant with the standard MBean convention.list""lowread-only
listener.security.protocol.mapMap between listener names and security protocols. This must be defined for the same security protocol to be usable in more than one port or IP. For example, internal and external traffic can be separated even if SSL is required for both. Concretely, the user could define listeners with names INTERNAL and EXTERNAL and this property as: `INTERNAL:SSL,EXTERNAL:SSL`. As shown, key and value are separated by a colon and map entries are separated by commas. Each listener name should only appear once in the map. Different security (SSL and SASL) settings can be configured for each listener by adding a normalised prefix (the listener name is lowercased) to the config name. For example, to set a different keystore for the INTERNAL listener, a config with name listener.name.internal.ssl.keystore.location would be set. If the config for the listener name is not set, the config will fallback to the generic config (i.e. ssl.keystore.location). stringPLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSLlowper-broker
log.message.downconversion.enableThis configuration controls whether down-conversion of message formats is enabled to satisfy consume requests. When set to false, broker will not perform down-conversion for consumers expecting an older message format. The broker responds with UNSUPPORTED_VERSION error for consume requests from such older clients. This configurationdoes not apply to any message format conversion that might be required for replication to followers.booleantruelowcluster-wide
metric.reportersA list of classes to use as metrics reporters. Implementing the org.apache.kafka.common.metrics.MetricsReporter interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.list""lowcluster-wide
metrics.num.samplesThe number of samples maintained to compute metrics.int2[1,...]lowread-only
metrics.recording.levelThe highest recording level for metrics.stringINFOlowread-only
metrics.sample.window.msThe window of time a metrics sample is computed over.long30000[1,...]lowread-only
password.encoder.cipher.algorithmThe Cipher algorithm used for encoding dynamically configured passwords.stringAES/CBC/PKCS5Paddinglowread-only
password.encoder.iterationsThe iteration count used for encoding dynamically configured passwords.int4096[1024,...]lowread-only
password.encoder.key.lengthThe key length used for encoding dynamically configured passwords.int128[8,...]lowread-only
password.encoder.keyfactory.algorithmThe SecretKeyFactory algorithm used for encoding dynamically configured passwords. Default is PBKDF2WithHmacSHA512 if available and PBKDF2WithHmacSHA1 otherwise.stringnulllowread-only
quota.window.numThe number of samples to retain in memory for client quotasint11[1,...]lowread-only
quota.window.size.secondsThe time span of each sample for client quotasint1[1,...]lowread-only
replication.quota.window.numThe number of samples to retain in memory for replication quotasint11[1,...]lowread-only
replication.quota.window.size.secondsThe time span of each sample for replication quotasint1[1,...]lowread-only
ssl.endpoint.identification.algorithmThe endpoint identification algorithm to validate server hostname using server certificate. stringhttpslowper-broker
ssl.principal.mapping.rulesA list of rules for mapping from distinguished name from the client certificate to short name. The rules are evaluated in order and the first rule that matches a principal name is used to map it to a short name. Any later rules in the list are ignored. By default, distinguished name of the X.500 certificate will be the principal. For more details on the format please see security authorization and acls. Note that this configuration is ignored if an extension of KafkaPrincipalBuilder is provided by the principal.builder.class configuration.listDEFAULTlowread-only
ssl.secure.random.implementationThe SecureRandom PRNG implementation to use for SSL cryptography operations. stringnulllowper-broker
transaction.abort.timed.out.transaction.cleanup.interval.msThe interval at which to rollback transactions that have timed outint60000[1,...]lowread-only
transaction.remove.expired.transaction.cleanup.interval.msThe interval at which to remove transactions that have expired due to transactional.id.expiration.ms passingint3600000[1,...]lowread-only
zookeeper.sync.time.msHow far a ZK follower can be behind a ZK leaderint2000lowread-only