Name Description Type Default Valid Values Importance
bootstrap.serversA list of host/port pairs to use for establishing the initial connection to the Kafka cluster. The client will make use of all servers irrespective of which servers are specified here for bootstrapping—this list only impacts the initial hosts used to discover the full set of servers. This list should be in the form host1:port1,host2:port2,.... Since these servers are just used for the initial connection to discover the full cluster membership (which may change dynamically), this list need not contain the full set of servers (you may want more than one, though, in case a server is down).listhigh
key.serializerSerializer class for key that implements the Serializer interface.classhigh
value.serializerSerializer class for value that implements the Serializer interface.classhigh
acksThe number of acknowledgments the producer requires the leader to have received before considering a request complete. This controls the durability of records that are sent. The following settings are common:
  • acks=0 If set to zero then the producer will not wait for any acknowledgment from the server at all. The record will be immediately added to the socket buffer and considered sent. No guarantee can be made that the server has received the record in this case, and the retries configuration will not take effect (as the client won't generally know of any failures). The offset given back for each record will always be set to -1.
  • acks=1 This will mean the leader will write the record to its local log but will respond without awaiting full acknowledgement from all followers. In this case should the leader fail immediately after acknowledging the record but before the followers have replicated it then the record will be lost.
  • acks=all This means the leader will wait for the full set of in-sync replicas to acknowledge the record. This guarantees that the record will not be lost as long as at least one in-sync replica remains alive. This is the strongest available guarantee.
string1[all, -1, 0, 1]high
buffer.memoryThe total bytes of memory the producer can use to buffer records waiting to be sent to the server. If records are sent faster than they can be delivered to the server the producer will either block or throw an exception based on the preference specified by block.on.buffer.full.

This setting should correspond roughly to the total memory the producer will use, but is not a hard bound since not all memory the producer uses is used for buffering. Some additional memory will be used for compression (if compression is enabled) as well as for maintaining in-flight requests.

long33554432[0,...]high
compression.typeThe compression type for all data generated by the producer. The default is none (i.e. no compression). Valid values are none, gzip, snappy, or lz4. Compression is of full batches of data, so the efficacy of batching will also impact the compression ratio (more batching means better compression).stringnonehigh
retriesSetting a value greater than zero will cause the client to resend any record whose send fails with a potentially transient error. Note that this retry is no different than if the client resent the record upon receiving the error. Allowing retries will potentially change the ordering of records because if two records are sent to a single partition, and the first fails and is retried but the second succeeds, then the second record may appear first.int0[0,...,2147483647]high
ssl.key.passwordThe password of the private key in the key store file. This is optional for client.passwordnullhigh
ssl.keystore.locationThe location of the key store file. This is optional for client and can be used for two-way authentication for client.stringnullhigh
ssl.keystore.passwordThe store password for the key store file.This is optional for client and only needed if ssl.keystore.location is configured. passwordnullhigh
ssl.truststore.locationThe location of the trust store file. stringnullhigh
ssl.truststore.passwordThe password for the trust store file. passwordnullhigh
batch.sizeThe producer will attempt to batch records together into fewer requests whenever multiple records are being sent to the same partition. This helps performance on both the client and the server. This configuration controls the default batch size in bytes.

No attempt will be made to batch records larger than this size.

Requests sent to brokers will contain multiple batches, one for each partition with data available to be sent.

A small batch size will make batching less common and may reduce throughput (a batch size of zero will disable batching entirely). A very large batch size may use memory a bit more wastefully as we will always allocate a buffer of the specified batch size in anticipation of additional records.

int16384[0,...]medium
client.idAn id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.string""medium
connections.max.idle.msClose idle connections after the number of milliseconds specified by this config.long540000medium
linger.msThe producer groups together any records that arrive in between request transmissions into a single batched request. Normally this occurs only under load when records arrive faster than they can be sent out. However in some circumstances the client may want to reduce the number of requests even under moderate load. This setting accomplishes this by adding a small amount of artificial delay—that is, rather than immediately sending out a record the producer will wait for up to the given delay to allow other records to be sent so that the sends can be batched together. This can be thought of as analogous to Nagle's algorithm in TCP. This setting gives the upper bound on the delay for batching: once we get batch.size worth of records for a partition it will be sent immediately regardless of this setting, however if we have fewer than this many bytes accumulated for this partition we will 'linger' for the specified time waiting for more records to show up. This setting defaults to 0 (i.e. no delay). Setting linger.ms=5, for example, would have the effect of reducing the number of requests sent but would add up to 5ms of latency to records sent in the absense of load.long0[0,...]medium
max.block.msThe configuration controls how long {@link KafkaProducer#send()} and {@link KafkaProducer#partitionsFor} will block.These methods can be blocked either because the buffer is full or metadata unavailable.Blocking in the user-supplied serializers or partitioner will not be counted against this timeout.long60000[0,...]medium
max.request.sizeThe maximum size of a request. This is also effectively a cap on the maximum record size. Note that the server has its own cap on record size which may be different from this. This setting will limit the number of record batches the producer will send in a single request to avoid sending huge requests.int1048576[0,...]medium
partitioner.classPartitioner class that implements the Partitioner interface.classclass org.apache.kafka.clients.producer.internals.DefaultPartitionermedium
receive.buffer.bytesThe size of the TCP receive buffer (SO_RCVBUF) to use when reading data.int32768[0,...]medium
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.int30000[0,...]medium
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.stringnullmedium
security.protocolProtocol used to communicate with brokers. Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL.stringPLAINTEXTmedium
send.buffer.bytesThe size of the TCP send buffer (SO_SNDBUF) to use when sending data.int131072[0,...]medium
ssl.enabled.protocolsThe list of protocols enabled for SSL connections.list[TLSv1.2, TLSv1.1, TLSv1]medium
ssl.keystore.typeThe file format of the key store file. This is optional for client.stringJKSmedium
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.stringTLSmedium
ssl.providerThe name of the security provider used for SSL connections. Default value is the default security provider of the JVM.stringnullmedium
ssl.truststore.typeThe file format of the trust store file.stringJKSmedium
timeout.msThe configuration controls the maximum amount of time the server will wait for acknowledgments from followers to meet the acknowledgment requirements the producer has specified with the acks configuration. If the requested number of acknowledgments are not met when the timeout elapses an error will be returned. This timeout is measured on the server side and does not include the network latency of the request.int30000[0,...]medium
block.on.buffer.fullWhen our memory buffer is exhausted we must either stop accepting new records (block) or throw errors. By default this setting is true and we block, however in some scenarios blocking is not desirable and it is better to immediately give an error. Setting this to false will accomplish that: the producer will throw a BufferExhaustedException if a recrord is sent and the buffer space is full.booleanfalselow
max.in.flight.requests.per.connectionThe maximum number of unacknowledged requests the client will send on a single connection before blocking. Note that if this setting is set to be greater than 1 and there are failed sends, there is a risk of message re-ordering due to retries (i.e., if retries are enabled).int5[1,...]low
metadata.fetch.timeout.msThe first time data is sent to a topic we must fetch metadata about that topic to know which servers host the topic's partitions. This fetch to succeed before throwing an exception back to the client.long60000[0,...]low
metadata.max.age.msThe period of time in milliseconds after which we force a refresh of metadata even if we haven't seen any partition leadership changes to proactively discover any new brokers or partitions.long300000[0,...]low
metric.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[]low
metrics.num.samplesThe number of samples maintained to compute metrics.int2[1,...]low
metrics.sample.window.msThe number of samples maintained to compute metrics.long30000[0,...]low
reconnect.backoff.msThe amount of time to wait before attempting to reconnect to a given host. This avoids repeatedly connecting to a host in a tight loop. This backoff applies to all requests sent by the consumer to the broker.long50[0,...]low
retry.backoff.msThe amount of time to wait before attempting to retry a failed fetch request to a given topic partition. This avoids repeated fetching-and-failing in a tight loop.long100[0,...]low
sasl.kerberos.kinit.cmdKerberos kinit command path.string/usr/bin/kinitlow
sasl.kerberos.min.time.before.reloginLogin thread sleep time between refresh attempts.long60000low
sasl.kerberos.ticket.renew.jitterPercentage of random jitter added to the renewal time.double0.05low
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.double0.8low
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.listnulllow
ssl.endpoint.identification.algorithmThe endpoint identification algorithm to validate server hostname using server certificate. stringnulllow
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.stringSunX509low
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.stringPKIXlow