NameDescriptionTypeDefaultValid ValuesImportancezookeeper.connectZookeeper host stringstringhighadvertised.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().stringnullhighadvertised.listenersListeners to publish to ZooKeeper for clients to use, if different than the listeners above. 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.stringnullhighadvertised.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.intnullhighauto.create.topics.enableEnable auto creation of topic on the serverbooleantruehighauto.leader.rebalance.enableEnables auto leader balancing. A background thread checks and triggers leader balance if required at regular intervalsbooleantruehighbackground.threadsThe number of threads to use for various background processing tasksint10[1,...]highbroker.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 idsstart from reserved.broker.max.id + 1.int-1highcompression.typeSpecify the final compression type for a given topic. This configuration accepts the standard compression codecs ('gzip', 'snappy', 'lz4'). It additionally accepts 'uncompressed' which is equivalent to no compression; and 'producer' which means retain the original compression codec set by the producer.stringproducerhighdelete.topic.enableEnables delete topic. Delete topic through the admin tool will have no effect if this config is turned offbooleanfalsehighhost.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""highleader.imbalance.check.interval.secondsThe frequency with which the partition rebalance check is triggered by the controllerlong300highleader.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.int10highlistenersListener List - Comma-separated list of URIs we will listen on and their protocols. 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,TRACE://:9091 PLAINTEXT://0.0.0.0:9092, TRACE://localhost:9093stringnullhighlog.dirThe directory in which the log data is kept (supplemental for log.dirs property)string/tmp/kafka-logshighlog.dirsThe directories in which the log data is kept. If not set, the value in log.dir is usedstringnullhighlog.flush.interval.messagesThe number of messages accumulated on a log partition before messages are flushed to disklong9223372036854775807[1,...]highlog.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 usedlongnullhighlog.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,...]highlog.flush.scheduler.interval.msThe frequency in ms that the log flusher checks whether any log needs to be flushed to disklong9223372036854775807highlog.retention.bytesThe maximum size of the log before deleting itlong-1highlog.retention.hoursThe number of hours to keep a log file before deleting it (in hours), tertiary to log.retention.ms propertyint168highlog.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 usedintnullhighlog.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 usedlongnullhighlog.roll.hoursThe maximum time before a new log segment is rolled out (in hours), secondary to log.roll.ms propertyint168[1,...]highlog.roll.jitter.hoursThe maximum jitter to subtract from logRollTimeMillis (in hours), secondary to log.roll.jitter.ms propertyint0[0,...]highlog.roll.jitter.msThe maximum jitter to subtract from logRollTimeMillis (in milliseconds). If not set, the value in log.roll.jitter.hours is usedlongnullhighlog.roll.msThe maximum time before a new log segment is rolled out (in milliseconds). If not set, the value in log.roll.hours is usedlongnullhighlog.segment.bytesThe maximum size of a single log fileint1073741824[14,...]highlog.segment.delete.delay.msThe amount of time to wait before deleting a file from the filesystemlong60000[0,...]highmessage.max.bytesThe maximum size of message that the server can receiveint1000012[0,...]highmin.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,...]highnum.io.threadsThe number of io threads that the server uses for carrying out network requestsint8[1,...]highnum.network.threadsthe number of network threads that the server uses for handling network requestsint3[1,...]highnum.recovery.threads.per.data.dirThe number of threads per data directory to be used for log recovery at startup and flushing at shutdownint1[1,...]highnum.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.int1highoffset.metadata.max.bytesThe maximum size for a metadata entry associated with an offset commitint4096highoffsets.commit.required.acksThe required acks before the commit can be accepted. In general, the default (-1) should not be overriddenshort-1highoffsets.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,...]highoffsets.load.buffer.sizeBatch size for reading from the offsets segments when loading offsets into the cache.int5242880[1,...]highoffsets.retention.check.interval.msFrequency at which to check for stale offsetslong600000[1,...]highoffsets.retention.minutesLog retention window in minutes for offsets topicint1440[1,...]highoffsets.topic.compression.codecCompression codec for the offsets topic - compression may be used to achieve "atomic" commitsint0highoffsets.topic.num.partitionsThe number of partitions for the offset commit topic (should not change after deployment)int50[1,...]highoffsets.topic.replication.factorThe replication factor for the offsets topic (set higher to ensure availability). To ensure that the effective replication factor of the offsets topic is the configured value, the number of alive brokers has to be at least the replication factor at the time of the first request for the offsets topic. If not, either the offsets topic creation will fail or it will get a replication factor of min(alive brokers, configured replication factor)short3[1,...]highoffsets.topic.segment.bytesThe offsets topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loadsint104857600[1,...]highportDEPRECATED: only used when `listeners` is not set. Use `listeners` instead. the port to listen and accept connections onint9092highqueued.max.requestsThe number of queued requests allowed before blocking the network threadsint500[1,...]highquota.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,...]highquota.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,...]highreplica.fetch.min.bytesMinimum bytes expected for each fetch response. If not enough bytes, wait up to replicaMaxWaitTimeMsint1highreplica.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 topicsint500highreplica.high.watermark.checkpoint.interval.msThe frequency with which the high watermark is saved out to disklong5000highreplica.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 isrlong10000highreplica.socket.receive.buffer.bytesThe socket receive buffer for network requestsint65536highreplica.socket.timeout.msThe socket timeout for network requests. Its value should be at least replica.fetch.wait.max.msint30000highrequest.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.int30000highsocket.receive.buffer.bytesThe SO_RCVBUF buffer of the socket sever sockets. If the value is -1, the OS default will be used.int102400highsocket.request.max.bytesThe maximum number of bytes in a socket requestint104857600[1,...]highsocket.send.buffer.bytesThe SO_SNDBUF buffer of the socket sever sockets. If the value is -1, the OS default will be used.int102400highunclean.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 lossbooleantruehighzookeeper.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 usedintnullhighzookeeper.session.timeout.msZookeeper session timeoutint6000highzookeeper.set.aclSet client to use secure ACLsbooleanfalsehighbroker.id.generation.enableEnable automatic broker id generation on the server. When enabled the value configured for reserved.broker.max.id should be reviewed.booleantruemediumbroker.rackRack of the broker. This will be used in rack aware replication assignment for fault tolerance. Examples: `RACK1`, `us-east-1d`stringnullmediumconnections.max.idle.msIdle connections timeout: the server socket processor threads close the connections that idle more than thislong600000mediumcontrolled.shutdown.enableEnable controlled shutdown of the serverbooleantruemediumcontrolled.shutdown.max.retriesControlled shutdown can fail for multiple reasons. This determines the number of retries when such failure happensint3mediumcontrolled.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.long5000mediumcontroller.socket.timeout.msThe socket timeout for controller-to-broker channelsint30000mediumdefault.replication.factordefault replication factors for automatically created topicsint1mediumfetch.purgatory.purge.interval.requestsThe purge interval (in number of requests) of the fetch request purgatoryint1000mediumgroup.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.int300000mediumgroup.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.int6000mediuminter.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.string0.10.1-IV2mediumlog.cleaner.backoff.msThe amount of time to sleep when there are no logs to cleanlong15000[0,...]mediumlog.cleaner.dedupe.buffer.sizeThe total memory used for log deduplication across all cleaner threadslong134217728mediumlog.cleaner.delete.retention.msHow long are delete records retained?long86400000mediumlog.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.booleantruemediumlog.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 collisionsdouble0.9mediumlog.cleaner.io.buffer.sizeThe total memory used for log cleaner I/O buffers across all cleaner threadsint524288[0,...]mediumlog.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 averagedouble1.7976931348623157E308mediumlog.cleaner.min.cleanable.ratioThe minimum ratio of dirty log to total log for a log to eligible for cleaningdouble0.5mediumlog.cleaner.min.compaction.lag.msThe minimum time a message will remain uncompacted in the log. Only applicable for logs that are being compacted.long0mediumlog.cleaner.threadsThe number of background threads to use for log cleaningint1[0,...]mediumlog.cleanup.policyThe default cleanup policy for segments beyond the retention window. A comma separated list of valid policies. Valid policies are: "delete" and "compact"list[delete][compact, delete]mediumlog.index.interval.bytesThe interval with which we add an entry to the offset indexint4096[0,...]mediumlog.index.size.max.bytesThe maximum size in bytes of the offset indexint10485760[4,...]mediumlog.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.string0.10.1-IV2mediumlog.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.long9223372036854775807[0,...]mediumlog.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]mediumlog.preallocateShould pre allocate file when create new segment? If you are using Kafka on Windows, you probably need to set it to true.booleanfalsemediumlog.retention.check.interval.msThe frequency in milliseconds that the log cleaner checks whether any log is eligible for deletionlong300000[1,...]mediummax.connections.per.ipThe maximum number of connections we allow from each ip addressint2147483647[1,...]mediummax.connections.per.ip.overridesPer-ip or hostname overrides to the default maximum number of connectionsstring""mediumnum.partitionsThe default number of log partitions per topicint1[1,...]mediumprincipal.builder.classThe fully qualified name of a class that implements the PrincipalBuilder interface, which is currently used to build the Principal for connections with the SSL SecurityProtocol.classclass org.apache.kafka.common.security.auth.DefaultPrincipalBuildermediumproducer.purgatory.purge.interval.requestsThe purge interval (in number of requests) of the producer request purgatoryint1000mediumreplica.fetch.backoff.msThe amount of time to sleep when fetch partition error occurs.int1000[0,...]mediumreplica.fetch.max.bytesThe number of bytes of messages to attempt to fetch for each partition. This is not an absolute maximum, if the first message in the first non-empty partition of the fetch is larger than this value, the message will still be returned to ensure that progress can be made. The maximum message size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config).int1048576[0,...]mediumreplica.fetch.response.max.bytesMaximum bytes expected for the entire fetch response. This is not an absolute maximum, if the first message in the first non-empty partition of the fetch is larger than this value, the message will still be returned to ensure that progress can be made. The maximum message size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config).int10485760[0,...]mediumreserved.broker.max.idMax number that can be used for a broker.idint1000[0,...]mediumsasl.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.list[GSSAPI]mediumsasl.kerberos.kinit.cmdKerberos kinit command path.string/usr/bin/kinitmediumsasl.kerberos.min.time.before.reloginLogin thread sleep time between refresh attempts.long60000mediumsasl.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.list[DEFAULT]mediumsasl.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.stringnullmediumsasl.kerberos.ticket.renew.jitterPercentage of random jitter added to the renewal time.double0.05mediumsasl.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.double0.8mediumsasl.mechanism.inter.broker.protocolSASL mechanism used for inter-broker communication. Default is GSSAPI.stringGSSAPImediumsecurity.inter.broker.protocolSecurity protocol used to communicate between brokers. Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL.stringPLAINTEXTmediumssl.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.listnullmediumssl.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]mediumssl.enabled.protocolsThe list of protocols enabled for SSL connections.list[TLSv1.2, TLSv1.1, TLSv1]mediumssl.key.passwordThe password of the private key in the key store file. This is optional for client.passwordnullmediumssl.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.stringSunX509mediumssl.keystore.locationThe location of the key store file. This is optional for client and can be used for two-way authentication for client.stringnullmediumssl.keystore.passwordThe store password for the key store file. This is optional for client and only needed if ssl.keystore.location is configured.passwordnullmediumssl.keystore.typeThe file format of the key store file. This is optional for client.stringJKSmediumssl.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.stringTLSmediumssl.providerThe name of the security provider used for SSL connections. Default value is the default security provider of the JVM.stringnullmediumssl.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.stringPKIXmediumssl.truststore.locationThe location of the trust store file.stringnullmediumssl.truststore.passwordThe password for the trust store file.passwordnullmediumssl.truststore.typeThe file format of the trust store file.stringJKSmediumauthorizer.class.nameThe authorizer class that should be used for authorizationstring""lowmetric.reportersA list of classes to use as metrics reporters. Implementing the MetricReporter interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.list[]lowmetrics.num.samplesThe number of samples maintained to compute metrics.int2[1,...]lowmetrics.sample.window.msThe window of time a metrics sample is computed over.long30000[1,...]lowquota.window.numThe number of samples to retain in memory for client quotasint11[1,...]lowquota.window.size.secondsThe time span of each sample for client quotasint1[1,...]lowreplication.quota.window.numThe number of samples to retain in memory for replication quotasint11[1,...]lowreplication.quota.window.size.secondsThe time span of each sample for replication quotasint1[1,...]lowssl.endpoint.identification.algorithmThe endpoint identification algorithm to validate server hostname using server certificate.stringnulllowssl.secure.random.implementationThe SecureRandom PRNG implementation to use for SSL cryptography operations.stringnulllowzookeeper.sync.time.msHow far a ZK follower can be behind a ZK leaderint2000low