3.7 Admin Configs

Below is the configuration of the Kafka Admin client library.

  • bootstrap.servers

    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).

    Type:list
    Default:
    Valid Values:
    Importance:high

  • ssl.key.password

    The password of the private key in the key store file orthe PEM key specified in `ssl.keystore.key’. This is required for clients only if two-way authentication is configured.

    Type:password
    Default:null
    Valid Values:
    Importance:high

  • ssl.keystore.certificate.chain

    Certificate chain in the format specified by ‘ssl.keystore.type’. Default SSL engine factory supports only PEM format with a list of X.509 certificates

    Type:password
    Default:null
    Valid Values:
    Importance:high

  • ssl.keystore.key

    Private key in the format specified by ‘ssl.keystore.type’. Default SSL engine factory supports only PEM format with PKCS#8 keys. If the key is encrypted, key password must be specified using ‘ssl.key.password’

    Type:password
    Default:null
    Valid Values:
    Importance:high

  • 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.

    Type:string
    Default:null
    Valid Values:
    Importance:high

  • 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. Key store password is not supported for PEM format.

    Type:password
    Default:null
    Valid Values:
    Importance:high

  • ssl.truststore.certificates

    Trusted certificates in the format specified by ‘ssl.truststore.type’. Default SSL engine factory supports only PEM format with X.509 certificates.

    Type:password
    Default:null
    Valid Values:
    Importance:high

  • ssl.truststore.location

    The location of the trust store file.

    Type:string
    Default:null
    Valid Values:
    Importance:high

  • ssl.truststore.password

    The password for the trust store file. If a password is not set, trust store file configured will still be used, but integrity checking is disabled. Trust store password is not supported for PEM format.

    Type:password
    Default:null
    Valid Values:
    Importance:high

  • client.dns.lookup

    Controls how the client uses DNS lookups. If set to use_all_dns_ips, connect to each returned IP address in sequence until a successful connection is established. After a disconnection, the next IP is used. Once all IPs have been used once, the client resolves the IP(s) from the hostname again (both the JVM and the OS cache DNS name lookups, however). If set to resolve_canonical_bootstrap_servers_only, resolve each bootstrap address into a list of canonical names. After the bootstrap phase, this behaves the same as use_all_dns_ips. If set to default (deprecated), attempt to connect to the first IP address returned by the lookup, even if the lookup returns multiple IP addresses.

    Type:string
    Default:use_all_dns_ips
    Valid Values:[default, use_all_dns_ips, resolve_canonical_bootstrap_servers_only]
    Importance:medium

  • client.id

    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.

    Type:string
    Default:“”
    Valid Values:
    Importance:medium

  • connections.max.idle.ms

    Close idle connections after the number of milliseconds specified by this config.

    Type:long
    Default:300000 (5 minutes)
    Valid Values:
    Importance:medium

  • default.api.timeout.ms

    Specifies the timeout (in milliseconds) for client APIs. This configuration is used as the default timeout for all client operations that do not specify a timeout parameter.

    Type:int
    Default:60000 (1 minute)
    Valid Values:[0,…]
    Importance:medium

  • receive.buffer.bytes

    The size of the TCP receive buffer (SO_RCVBUF) to use when reading data. If the value is -1, the OS default will be used.

    Type:int
    Default:65536 (64 kibibytes)
    Valid Values:[-1,…]
    Importance:medium

  • 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.

    Type:int
    Default:30000 (30 seconds)
    Valid Values:[0,…]
    Importance:medium

  • sasl.client.callback.handler.class

    The fully qualified name of a SASL client callback handler class that implements the AuthenticateCallbackHandler interface.

    Type:class
    Default:null
    Valid Values:
    Importance:medium

  • sasl.jaas.config

    JAAS 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;

    Type:password
    Default:null
    Valid Values:
    Importance: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.

    Type:string
    Default:null
    Valid Values:
    Importance:medium

  • sasl.login.callback.handler.class

    The 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.CustomScramLoginCallbackHandler

    Type:class
    Default:null
    Valid Values:
    Importance:medium

  • sasl.login.class

    The 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.CustomScramLogin

    Type:class
    Default:null
    Valid Values:
    Importance:medium

  • sasl.mechanism

    SASL mechanism used for client connections. This may be any mechanism for which a security provider is available. GSSAPI is the default mechanism.

    Type:string
    Default:GSSAPI
    Valid Values:
    Importance:medium

  • security.protocol

    Protocol used to communicate with brokers. Valid values are: PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL.

    Type:string
    Default:PLAINTEXT
    Valid Values:
    Importance:medium

  • send.buffer.bytes

    The size of the TCP send buffer (SO_SNDBUF) to use when sending data. If the value is -1, the OS default will be used.

    Type:int
    Default:131072 (128 kibibytes)
    Valid Values:[-1,…]
    Importance:medium

  • socket.connection.setup.timeout.max.ms

    The maximum amount of time the client will wait for the socket connection to be established. The connection setup timeout will increase exponentially for each consecutive connection failure up to this maximum. To avoid connection storms, a randomization factor of 0.2 will be applied to the timeout resulting in a random range between 20% below and 20% above the computed value.

    Type:long
    Default:127000 (127 seconds)
    Valid Values:
    Importance:medium

  • socket.connection.setup.timeout.ms

    The amount of time the client will wait for the socket connection to be established. If the connection is not built before the timeout elapses, clients will close the socket channel.

    Type:long
    Default:10000 (10 seconds)
    Valid Values:
    Importance:medium

  • ssl.enabled.protocols

    The list of protocols enabled for SSL connections. The default is ‘TLSv1.2,TLSv1.3’ when running with Java 11 or newer, ‘TLSv1.2’ otherwise. With the default value for Java 11, clients and servers will prefer TLSv1.3 if both support it and fallback to TLSv1.2 otherwise (assuming both support at least TLSv1.2). This default should be fine for most cases. Also see the config documentation for `ssl.protocol`.

    Type:list
    Default:TLSv1.2
    Valid Values:
    Importance:medium

  • ssl.keystore.type

    The file format of the key store file. This is optional for client.

    Type:string
    Default:JKS
    Valid Values:
    Importance:medium

  • ssl.protocol

    The SSL protocol used to generate the SSLContext. The default is ‘TLSv1.3’ when running with Java 11 or newer, ‘TLSv1.2’ otherwise. This value should be fine for most use cases. Allowed values in recent JVMs are ‘TLSv1.2’ and ‘TLSv1.3’. ‘TLS’, ‘TLSv1.1’, ‘SSL’, ‘SSLv2’ and ‘SSLv3’ may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities. With the default value for this config and ‘ssl.enabled.protocols’, clients will downgrade to ‘TLSv1.2’ if the server does not support ‘TLSv1.3’. If this config is set to ‘TLSv1.2’, clients will not use ‘TLSv1.3’ even if it is one of the values in ssl.enabled.protocols and the server only supports ‘TLSv1.3’.

    Type:string
    Default:TLSv1.2
    Valid Values:
    Importance:medium

  • ssl.provider

    The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.

    Type:string
    Default:null
    Valid Values:
    Importance:medium

  • ssl.truststore.type

    The file format of the trust store file.

    Type:string
    Default:JKS
    Valid Values:
    Importance:medium

  • metadata.max.age.ms

    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.

    Type:long
    Default:300000 (5 minutes)
    Valid Values:[0,…]
    Importance:low

  • metric.reporters

    A 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.

    Type:list
    Default:“”
    Valid Values:
    Importance:low

  • metrics.num.samples

    The number of samples maintained to compute metrics.

    Type:int
    Default:2
    Valid Values:[1,…]
    Importance:low

  • metrics.recording.level

    The highest recording level for metrics.

    Type:string
    Default:INFO
    Valid Values:[INFO, DEBUG, TRACE]
    Importance:low

  • metrics.sample.window.ms

    The window of time a metrics sample is computed over.

    Type:long
    Default:30000 (30 seconds)
    Valid Values:[0,…]
    Importance:low

  • reconnect.backoff.max.ms

    The maximum amount of time in milliseconds to wait when reconnecting to a broker that has repeatedly failed to connect. If provided, the backoff per host will increase exponentially for each consecutive connection failure, up to this maximum. After calculating the backoff increase, 20% random jitter is added to avoid connection storms.

    Type:long
    Default:1000 (1 second)
    Valid Values:[0,…]
    Importance:low

  • reconnect.backoff.ms

    The base 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 connection attempts by the client to a broker.

    Type:long
    Default:50
    Valid Values:[0,…]
    Importance:low

  • retries

    Setting a value greater than zero will cause the client to resend any request that fails with a potentially transient error. It is recommended to set the value to either zero or `MAX_VALUE` and use corresponding timeout parameters to control how long a client should retry a request.

    Type:int
    Default:2147483647
    Valid Values:[0,…,2147483647]
    Importance:low

  • retry.backoff.ms

    The amount of time to wait before attempting to retry a failed request. This avoids repeatedly sending requests in a tight loop under some failure scenarios.

    Type:long
    Default:100
    Valid Values:[0,…]
    Importance:low

  • sasl.kerberos.kinit.cmd

    Kerberos kinit command path.

    Type:string
    Default:/usr/bin/kinit
    Valid Values:
    Importance:low

  • sasl.kerberos.min.time.before.relogin

    Login thread sleep time between refresh attempts.

    Type:long
    Default:60000
    Valid Values:
    Importance:low

  • sasl.kerberos.ticket.renew.jitter

    Percentage of random jitter added to the renewal time.

    Type:double
    Default:0.05
    Valid Values:
    Importance:low

  • 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.

    Type:double
    Default:0.8
    Valid Values:
    Importance:low

  • sasl.login.refresh.buffer.seconds

    The 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.

    Type:short
    Default:300
    Valid Values:[0,…,3600]
    Importance:low

  • sasl.login.refresh.min.period.seconds

    The 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.

    Type:short
    Default:60
    Valid Values:[0,…,900]
    Importance:low

  • sasl.login.refresh.window.factor

    Login 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.

    Type:double
    Default:0.8
    Valid Values:[0.5,…,1.0]
    Importance:low

  • sasl.login.refresh.window.jitter

    The 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.

    Type:double
    Default:0.05
    Valid Values:[0.0,…,0.25]
    Importance:low

  • security.providers

    A list of configurable creator classes each returning a provider implementing security algorithms. These classes should implement the org.apache.kafka.common.security.auth.SecurityProviderCreator interface.

    Type:string
    Default:null
    Valid Values:
    Importance:low

  • 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.

    Type:list
    Default:null
    Valid Values:
    Importance:low

  • ssl.endpoint.identification.algorithm

    The endpoint identification algorithm to validate server hostname using server certificate.

    Type:string
    Default:https
    Valid Values:
    Importance:low

  • ssl.engine.factory.class

    The class of type org.apache.kafka.common.security.auth.SslEngineFactory to provide SSLEngine objects. Default value is org.apache.kafka.common.security.ssl.DefaultSslEngineFactory

    Type:class
    Default:null
    Valid Values:
    Importance:low

  • 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.

    Type:string
    Default:SunX509
    Valid Values:
    Importance:low

  • ssl.secure.random.implementation

    The SecureRandom PRNG implementation to use for SSL cryptography operations.

    Type:string
    Default:null
    Valid Values:
    Importance:low

  • 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.

    Type:string
    Default:PKIX
    Valid Values:
    Importance:low