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Broker Configs
Broker Configs
The essential configurations are the following:
broker.idlog.dirszookeeper.connectTopic-level configurations and defaults are discussed in more detail below.Name Description Type Default Valid Values Importance zookeeper.connect Zookeeper host string string high advertised.host.name DEPRECATED: 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(). string null high advertised.listeners Listeners 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. string null high advertised.port DEPRECATED: 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. int null high auto.create.topics.enable Enable auto creation of topic on the server boolean true high auto.leader.rebalance.enable Enables auto leader balancing. A background thread checks and triggers leader balance if required at regular intervals boolean true high background.threads The number of threads to use for various background processing tasks int 10 [1,...] high broker.id The 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 -1 high compression.type Specify 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. string producer high delete.topic.enable Enables delete topic. Delete topic through the admin tool will have no effect if this config is turned off boolean true high host.name DEPRECATED: 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 interfaces string "" high leader.imbalance.check.interval.seconds The frequency with which the partition rebalance check is triggered by the controller long 300 high leader.imbalance.per.broker.percentage The 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. int 10 high listeners Listener 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 string null high log.dir The directory in which the log data is kept (supplemental for log.dirs property) string /tmp/kafka-logs high log.dirs The directories in which the log data is kept. If not set, the value in log.dir is used string null high log.flush.interval.messages The number of messages accumulated on a log partition before messages are flushed to disk long 9223372036854775807 [1,...] high log.flush.interval.ms The 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 used long null high log.flush.offset.checkpoint.interval.ms The frequency with which we update the persistent record of the last flush which acts as the log recovery point int 60000 [0,...] high log.flush.scheduler.interval.ms The frequency in ms that the log flusher checks whether any log needs to be flushed to disk long 9223372036854775807 high log.flush.start.offset.checkpoint.interval.ms The frequency with which we update the persistent record of log start offset int 60000 [0,...] high log.retention.bytes The maximum size of the log before deleting it long -1 high log.retention.hours The number of hours to keep a log file before deleting it (in hours), tertiary to log.retention.ms property int 168 high log.retention.minutes The 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 used int null high log.retention.ms The number of milliseconds to keep a log file before deleting it (in milliseconds), If not set, the value in log.retention.minutes is used long null high log.roll.hours The maximum time before a new log segment is rolled out (in hours), secondary to log.roll.ms property int 168 [1,...] high log.roll.jitter.hours The maximum jitter to subtract from logRollTimeMillis (in hours), secondary to log.roll.jitter.ms property int 0 [0,...] high log.roll.jitter.ms The maximum jitter to subtract from logRollTimeMillis (in milliseconds). If not set, the value in log.roll.jitter.hours is used long null high log.roll.ms The maximum time before a new log segment is rolled out (in milliseconds). If not set, the value in log.roll.hours is used long null high log.segment.bytes The maximum size of a single log file int 1073741824 [14,...] high log.segment.delete.delay.ms The amount of time to wait before deleting a file from the filesystem long 60000 [0,...] high 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.bytesconfig.int 1000012 [0,...] high min.insync.replicas When 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.int 1 [1,...] high num.io.threads The number of threads that the server uses for processing requests, which may include disk I/O int 8 [1,...] high num.network.threads The number of threads that the server uses for receiving requests from the network and sending responses to the network int 3 [1,...] high num.recovery.threads.per.data.dir The number of threads per data directory to be used for log recovery at startup and flushing at shutdown int 1 [1,...] high num.replica.fetchers Number 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. int 1 high offset.metadata.max.bytes The maximum size for a metadata entry associated with an offset commit int 4096 high offsets.commit.required.acks The required acks before the commit can be accepted. In general, the default (-1) should not be overridden short -1 high offsets.commit.timeout.ms Offset 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. int 5000 [1,...] high offsets.load.buffer.size Batch size for reading from the offsets segments when loading offsets into the cache. int 5242880 [1,...] high offsets.retention.check.interval.ms Frequency at which to check for stale offsets long 600000 [1,...] high offsets.retention.minutes Offsets older than this retention period will be discarded int 1440 [1,...] high offsets.topic.compression.codec Compression codec for the offsets topic - compression may be used to achieve "atomic" commits int 0 high offsets.topic.num.partitions The number of partitions for the offset commit topic (should not change after deployment) int 50 [1,...] high offsets.topic.replication.factor The 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. short 3 [1,...] high offsets.topic.segment.bytes The offsets topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loads int 104857600 [1,...] high port DEPRECATED: only used when `listeners` is not set. Use `listeners` instead. the port to listen and accept connections on int 9092 high queued.max.requests The number of queued requests allowed before blocking the network threads int 500 [1,...] high quota.consumer.default DEPRECATED: Used only when dynamic default quotas are not configured for long 9223372036854775807 [1,...] high quota.producer.default DEPRECATED: Used only when dynamic default quotas are not configured for , or long 9223372036854775807 [1,...] high replica.fetch.min.bytes Minimum bytes expected for each fetch response. If not enough bytes, wait up to replicaMaxWaitTimeMs int 1 high replica.fetch.wait.max.ms max 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 topics int 500 high replica.high.watermark.checkpoint.interval.ms The frequency with which the high watermark is saved out to disk long 5000 high replica.lag.time.max.ms If 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 isr long 10000 high replica.socket.receive.buffer.bytes The socket receive buffer for network requests int 65536 high replica.socket.timeout.ms The socket timeout for network requests. Its value should be at least replica.fetch.wait.max.ms int 30000 high request.timeout.ms The 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. int 30000 high socket.receive.buffer.bytes The SO_RCVBUF buffer of the socket sever sockets. If the value is -1, the OS default will be used. int 102400 high socket.request.max.bytes The maximum number of bytes in a socket request int 104857600 [1,...] high socket.send.buffer.bytes The SO_SNDBUF buffer of the socket sever sockets. If the value is -1, the OS default will be used. int 102400 high transaction.max.timeout.ms The 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. int 900000 [1,...] high transaction.state.log.load.buffer.size Batch size for reading from the transaction log segments when loading producer ids and transactions into the cache. int 5242880 [1,...] high transaction.state.log.min.isr Overridden min.insync.replicas config for the transaction topic. int 2 [1,...] high transaction.state.log.num.partitions The number of partitions for the transaction topic (should not change after deployment). int 50 [1,...] high transaction.state.log.replication.factor The 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. short 3 [1,...] high transaction.state.log.segment.bytes The transaction topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loads int 104857600 [1,...] high transactional.id.expiration.ms The 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. int 604800000 [1,...] high unclean.leader.election.enable 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 boolean false high zookeeper.connection.timeout.ms The max time that the client waits to establish a connection to zookeeper. If not set, the value in zookeeper.session.timeout.ms is used int null high zookeeper.session.timeout.ms Zookeeper session timeout int 6000 high zookeeper.set.acl Set client to use secure ACLs boolean false high broker.id.generation.enable Enable automatic broker id generation on the server. When enabled the value configured for reserved.broker.max.id should be reviewed. boolean true medium broker.rack Rack of the broker. This will be used in rack aware replication assignment for fault tolerance. Examples: `RACK1`, `us-east-1d` string null medium connections.max.idle.ms Idle connections timeout: the server socket processor threads close the connections that idle more than this long 600000 medium controlled.shutdown.enable Enable controlled shutdown of the server boolean true medium controlled.shutdown.max.retries Controlled shutdown can fail for multiple reasons. This determines the number of retries when such failure happens int 3 medium controlled.shutdown.retry.backoff.ms Before 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. long 5000 medium controller.socket.timeout.ms The socket timeout for controller-to-broker channels int 30000 medium default.replication.factor default replication factors for automatically created topics int 1 medium delete.records.purgatory.purge.interval.requests The purge interval (in number of requests) of the delete records request purgatory int 1 medium fetch.purgatory.purge.interval.requests The purge interval (in number of requests) of the fetch request purgatory int 1000 medium group.initial.rebalance.delay.ms The 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. int 3000 medium group.max.session.timeout.ms The 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. int 300000 medium group.min.session.timeout.ms The 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. int 6000 medium inter.broker.listener.name Name 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. string null medium inter.broker.protocol.version Specify 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. string 1.0-IV0 medium log.cleaner.backoff.ms The amount of time to sleep when there are no logs to clean long 15000 [0,...] medium log.cleaner.dedupe.buffer.size The total memory used for log deduplication across all cleaner threads long 134217728 medium log.cleaner.delete.retention.ms How long are delete records retained? long 86400000 medium log.cleaner.enable Enable 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. boolean true medium log.cleaner.io.buffer.load.factor Log 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 collisions double 0.9 medium log.cleaner.io.buffer.size The total memory used for log cleaner I/O buffers across all cleaner threads int 524288 [0,...] medium log.cleaner.io.max.bytes.per.second The log cleaner will be throttled so that the sum of its read and write i/o will be less than this value on average double 1.7976931348623157E308 medium log.cleaner.min.cleanable.ratio The minimum ratio of dirty log to total log for a log to eligible for cleaning double 0.5 medium log.cleaner.min.compaction.lag.ms The minimum time a message will remain uncompacted in the log. Only applicable for logs that are being compacted. long 0 medium log.cleaner.threads The number of background threads to use for log cleaning int 1 [0,...] medium log.cleanup.policy The 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] medium log.index.interval.bytes The interval with which we add an entry to the offset index int 4096 [0,...] medium log.index.size.max.bytes The maximum size in bytes of the offset index int 10485760 [4,...] medium log.message.format.version Specify 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. string 1.0-IV0 medium log.message.timestamp.difference.max.ms The 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. long 9223372036854775807 medium log.message.timestamp.type Define whether the timestamp in the message is message create time or log append time. The value should be either `CreateTime` or `LogAppendTime` string CreateTime [CreateTime, LogAppendTime] medium log.preallocate Should pre allocate file when create new segment? If you are using Kafka on Windows, you probably need to set it to true. boolean false medium log.retention.check.interval.ms The frequency in milliseconds that the log cleaner checks whether any log is eligible for deletion long 300000 [1,...] medium max.connections.per.ip The maximum number of connections we allow from each ip address int 2147483647 [1,...] medium max.connections.per.ip.overrides Per-ip or hostname overrides to the default maximum number of connections string "" medium num.partitions The default number of log partitions per topic int 1 [1,...] medium principal.builder.class The 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 name will be 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.rulesif GSSAPI is in use, and the SASL authentication ID for other mechanisms. For PLAINTEXT, the principal will be ANONYMOUS.class null medium producer.purgatory.purge.interval.requests The purge interval (in number of requests) of the producer request purgatory int 1000 medium queued.max.request.bytes The number of queued bytes allowed before no more requests are read long -1 medium replica.fetch.backoff.ms The amount of time to sleep when fetch partition error occurs. int 1000 [0,...] medium replica.fetch.max.bytes The 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) ormax.message.bytes(topic config).int 1048576 [0,...] medium replica.fetch.response.max.bytes Maximum 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) ormax.message.bytes(topic config).int 10485760 [0,...] medium reserved.broker.max.id Max number that can be used for a broker.id int 1000 [0,...] medium sasl.enabled.mechanisms The 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 medium sasl.kerberos.kinit.cmd Kerberos kinit command path. string /usr/bin/kinit medium sasl.kerberos.min.time.before.relogin Login thread sleep time between refresh attempts. long 60000 medium sasl.kerberos.principal.to.local.rules A 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.classconfiguration.list DEFAULT medium sasl.kerberos.service.name The Kerberos principal name that Kafka runs as. This can be defined either in Kafka's JAAS config or in Kafka's config. string null medium sasl.kerberos.ticket.renew.jitter Percentage of random jitter added to the renewal time. double 0.05 medium sasl.kerberos.ticket.renew.window.factor Login 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. double 0.8 medium sasl.mechanism.inter.broker.protocol SASL mechanism used for inter-broker communication. Default is GSSAPI. string GSSAPI medium security.inter.broker.protocol Security 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. string PLAINTEXT medium ssl.cipher.suites A 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 null medium ssl.client.auth Configures kafka broker to request client authentication. The following settings are common: ssl.client.auth=requiredIf set to required client authentication is required.ssl.client.auth=requestedThis means client authentication is optional. unlike requested , if this option is set client can choose not to provide authentication information about itselfssl.client.auth=noneThis means client authentication is not needed.
string none [required, requested, none] medium ssl.enabled.protocols The list of protocols enabled for SSL connections. list TLSv1.2,TLSv1.1,TLSv1 medium ssl.key.password The password of the private key in the key store file. This is optional for client. password null medium ssl.keymanager.algorithm The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine. string SunX509 medium ssl.keystore.location The location of the key store file. This is optional for client and can be used for two-way authentication for client. string null medium ssl.keystore.password The store password for the key store file. This is optional for client and only needed if ssl.keystore.location is configured. password null medium ssl.keystore.type The file format of the key store file. This is optional for client. string JKS medium ssl.protocol The 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. string TLS medium ssl.provider The name of the security provider used for SSL connections. Default value is the default security provider of the JVM. string null medium ssl.trustmanager.algorithm The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine. string PKIX medium ssl.truststore.location The location of the trust store file. string null medium ssl.truststore.password The password for the trust store file. If a password is not set access to the truststore is still available, but integrity checking is disabled. password null medium ssl.truststore.type The file format of the trust store file. string JKS medium alter.config.policy.class.name The alter configs policy class that should be used for validation. The class should implement the org.apache.kafka.server.policy.AlterConfigPolicyinterface.class null low authorizer.class.name The authorizer class that should be used for authorization string "" low create.topic.policy.class.name The create topic policy class that should be used for validation. The class should implement the org.apache.kafka.server.policy.CreateTopicPolicyinterface.class null low listener.security.protocol.map Map 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`). string PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL low metric.reporters A list of classes to use as metrics reporters. Implementing the org.apache.kafka.common.metrics.MetricsReporterinterface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.list "" low metrics.num.samples The number of samples maintained to compute metrics. int 2 [1,...] low metrics.recording.level The highest recording level for metrics. string INFO low metrics.sample.window.ms The window of time a metrics sample is computed over. long 30000 [1,...] low quota.window.num The number of samples to retain in memory for client quotas int 11 [1,...] low quota.window.size.seconds The time span of each sample for client quotas int 1 [1,...] low replication.quota.window.num The number of samples to retain in memory for replication quotas int 11 [1,...] low replication.quota.window.size.seconds The time span of each sample for replication quotas int 1 [1,...] low ssl.endpoint.identification.algorithm The endpoint identification algorithm to validate server hostname using server certificate. string null low ssl.secure.random.implementation The SecureRandom PRNG implementation to use for SSL cryptography operations. string null low transaction.abort.timed.out.transaction.cleanup.interval.ms The interval at which to rollback transactions that have timed out int 60000 [1,...] low transaction.remove.expired.transaction.cleanup.interval.ms The interval at which to remove transactions that have expired due to transactional.id.expiration.mspassingint 3600000 [1,...] low zookeeper.sync.time.ms How far a ZK follower can be behind a ZK leader int 2000 low
More details about broker configuration can be found in the scala class kafka.server.KafkaConfig.