Name	Type	Default	Required	Importance	Description
bootstrap.servers	list		true	high	A 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).
key.deserializer	class		true	high	Deserializer class for key that implements the Deserializer interface.
value.deserializer	class		true	high	Deserializer class for value that implements the Deserializer interface.
fetch.min.bytes	int	1024	true	high	The minimum amount of data the server should return for a fetch request. If insufficient data is available the request will wait for that much data to accumulate before answering the request. The default setting of 1 byte means that fetch requests are answered as soon as a single byte of data is available or the fetch request times out waiting for data to arrive. Setting this to something greater than 1 will cause the server to wait for larger amounts of data to accumulate which can improve server throughput a bit at the cost of some additional latency.
group.id	string	""	true	high	A unique string that identifies the consumer group this consumer belongs to. This property is required if the consumer uses either the group management functionality by using subscribe(topic) or the Kafka-based offset management strategy.
heartbeat.interval.ms	int	3000	true	high	The expected time between heartbeats to the consumer coordinator when using Kafka's group management facilities. Heartbeats are used to ensure that the consumer's session stays active and to facilitate rebalancing when new consumers join or leave the group. The value must be set lower than session.timeout.ms, but typically should be set no higher than 1/3 of that value. It can be adjusted even lower to control the expected time for normal rebalances.
max.partition.fetch.bytes	int	1048576	true	high	The maximum amount of data per-partition the server will return. The maximum total memory used for a request will be #partitions * max.partition.fetch.bytes. This size must be at least as large as the maximum message size the server allows or else it is possible for the producer to send messages larger than the consumer can fetch. If that happens, the consumer can get stuck trying to fetch a large message on a certain partition.
session.timeout.ms	int	30000	true	high	The timeout used to detect failures when using Kafka's group management facilities.
ssl.key.password	string		false	high	The password of the private key in the key store file. This is optional for client.
ssl.keystore.location	string		false	high	The location of the key store file. This is optional for client and can be used for two-way authentication for client.
ssl.keystore.password	string		false	high	The store password for the key store file.This is optional for client and only needed if ssl.keystore.location is configured.
ssl.truststore.location	string		false	high	The location of the trust store file.
ssl.truststore.password	string		false	high	The password for the trust store file.
auto.offset.reset	string	latest	true	medium	What to do when there is no initial offset in Kafka or if the current offset does not exist any more on the server (e.g. because that data has been deleted): earliest: automatically reset the offset to the earliest offset latest: automatically reset the offset to the latest offset none: throw exception to the consumer if no previous offset is found for the consumer's group anything else: throw exception to the consumer.
connections.max.idle.ms	long	540000	true	medium	Close idle connections after the number of milliseconds specified by this config.
enable.auto.commit	boolean	true	true	medium	If true the consumer's offset will be periodically committed in the background.
partition.assignment.strategy	list	[org.apache.kafka.clients.consumer.RangeAssignor]	true	medium	The class name of the partition assignment strategy that the client will use to distribute partition ownership amongst consumer instances when group management is used
receive.buffer.bytes	int	32768	true	medium	The size of the TCP receive buffer (SO_RCVBUF) to use when reading data.
request.timeout.ms	int	40000	true	medium	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.
sasl.kerberos.service.name	string		false	medium	The Kerberos principal name that Kafka runs as. This can be defined either in Kafka's JAAS config or in Kafka's config.
security.protocol	string	PLAINTEXT	true	medium	Protocol used to communicate with brokers. Currently only PLAINTEXT and SSL are supported.
send.buffer.bytes	int	131072	true	medium	The size of the TCP send buffer (SO_SNDBUF) to use when sending data.
ssl.enabled.protocols	list	[TLSv1.2, TLSv1.1, TLSv1]	true	medium	The list of protocols enabled for SSL connections. TLSv1.2, TLSv1.1 and TLSv1 are enabled by default.
ssl.keystore.type	string	JKS	true	medium	The file format of the key store file. This is optional for client. Default value is JKS
ssl.protocol	string	TLS	true	medium	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.
ssl.provider	string		false	medium	The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.
ssl.truststore.type	string	JKS	true	medium	The file format of the trust store file. Default value is JKS.
auto.commit.interval.ms	long	5000	true	low	The frequency in milliseconds that the consumer offsets are auto-committed to Kafka if enable.auto.commit is set to true.
check.crcs	boolean	true	true	low	Automatically check the CRC32 of the records consumed. This ensures no on-the-wire or on-disk corruption to the messages occurred. This check adds some overhead, so it may be disabled in cases seeking extreme performance.
client.id	string	""	true	low	An 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.
fetch.max.wait.ms	int	500	true	low	The maximum amount of time the server will block before answering the fetch request if there isn't sufficient data to immediately satisfy the requirement given by fetch.min.bytes.
metadata.max.age.ms	long	300000	true	low	The 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.
metric.reporters	list	[]	true	low	A 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.
metrics.num.samples	int	2	true	low	The number of samples maintained to compute metrics.
metrics.sample.window.ms	long	30000	true	low	The number of samples maintained to compute metrics.
principal.builder.class	class	class org.apache.kafka.common.security.auth.DefaultPrincipalBuilder	true	low	principal builder to generate a java Principal. This config is optional for client.
reconnect.backoff.ms	long	50	true	low	The 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.
retry.backoff.ms	long	100	true	low	The 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.
sasl.kerberos.kinit.cmd	string	/usr/bin/kinit	true	low	Kerberos kinit command path. Default is /usr/bin/kinit
sasl.kerberos.min.time.before.relogin	long	60000	true	low	Login thread sleep time between refresh attempts.
sasl.kerberos.ticket.renew.jitter	double	0.05	true	low	Percentage of random jitter added to the renewal time.
sasl.kerberos.ticket.renew.window.factor	double	0.8	true	low	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.
ssl.cipher.suites	list		false	low	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.
ssl.endpoint.identification.algorithm	string		false	low	The endpoint identification algorithm to validate server hostname using server certificate.
ssl.keymanager.algorithm	string	SunX509	true	low	The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.
ssl.trustmanager.algorithm	string	PKIX	true	low	The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.