Replicator Configuration Reference for Confluent Platform¶

This section is a reference for Replicator configuration options.

For more about Replicator features, use cases, and use in failover scenarios, see Replicate Multi-Datacenter Topics Across Kafka Clusters in Confluent Platform.

To use this connector, specify the name of the connector class in the connector.class configuration property.

connector.class=io.confluent.connect.replicator.ReplicatorSourceConnector

Connector-specific configuration properties are described below.

Source Topics¶

Important

The __consumer_timestamps topic will not be copied from source to destination as this topic is relevant only to Replicator offset translation. For more information regarding offset translation, see Understanding consumer offset translation.

topic.regex

Regex of topics to replicate to the destination cluster. To learn more about regular expressions, see Java Regular Expressions.

Type: string
Default: null
Importance: high

Important

Replicator will not copy the internal __consumer_offsets or __transaction_state topics from the source cluster even if matched in topic.regex or topic.whitelist.

Note

The topic.regex property and the following two topic.whitelist and topic.blacklist properties are applied in the following order:

Any topics specified in topic.blacklist will not be replicated.
Any topics specified in topic.whitelist or matched by topic.regex will be replicated (whitelisted topics do not have to match the regex).

All three properties can be provided in a single Replicator configuration. They work cooperatively to determine which topics to replicate. For instance, given a sequence of topic names topic1, topic2, topic3, and topic4, you could specify a topic.whitelist of topic1, a topic.regex of topic[2,3,4], and a topic.blacklist of topic4. Replicator would combine these constraints to produce a final list of replicated topics containing topic1, topic2, and topic3.

If all three properties are left with their default values, no topics are replicated.

topic.whitelist

Whitelist of topics to be replicated.

Type: list
Default: “”
Importance: high

Important

At startup, Replicator lists the topics to replicate. Replicator will fail if any topic in topic.whitelist cannot be listed, either because the topic does not exist or because there are insufficient ACLs for it. The Replicator principal must have permissions to describe ACLs on every topic in the list. For more information, see Replicator Security.

For Replicator version 5.5 and later, topics listed in topic.whitelist must exist in the source cluster. If you want to topics to be created after starting Replicator, use topic.regex for these instead.

topic.blacklist

Topics to exclude from replication.

Type: list
Default: “”
Importance: high

topic.poll.interval.ms

How often to poll the source cluster for new topics matching topic.whitelist or topic.regex.

Type: int
Default: 120000
Valid Values: [0,…]
Importance: low

Important

The topic.regex, topic.whitelist and topic.blacklist configurations apply in the following order:

Any topics specified in topic.blacklist will not be replicated.
Any topics specified in topic.whitelist or matched by topic.regex will be replicated (whitelisted topics do not have to match the regex).

If all 3 properties are left with their default values then no topics will be replicated.

Source Data Conversion¶

src.key.converter

Converter for the key field of messages retrieved from the source cluster.

Type: class
Default: io.confluent.connect.replicator.util.ByteArrayConverter
Importance: low

src.value.converter

Converter for the value field of messages retrieved from the source cluster.

Type: class
Default: io.confluent.connect.replicator.util.ByteArrayConverter
Importance: low

src.header.converter

HeaderConverter class used to convert serialized Kafka headers to Kafka Connect headers. Default value is ByteArrayConverter, which simply passes the input bytes into the destination record.

Type: class
Default: io.confluent.connect.replicator.util.ByteArrayConverter
Importance: low

Source Kafka¶

The following configuration options are common properties that are used across Kafka clients. Replicator uses these options to connect with the source cluster (consumer, adminclient). Valid client properties that use the src.kafka prefix will be forwarded to clients that connect to the source cluster. You should use src.kafka if the configurations for consumer and adminclient are the same.

src.kafka.bootstrap.servers

A list of host and port pairs to use for establishing the initial connection to the source Kafka cluster. The client will use all servers, irrespective of which servers are designated here for bootstrapping. This list only controls the initial hosts used to discover the full set of servers. This list must be in the form host1:port1,host2:port2,.... These servers are only used for the initial connection, to discover the full cluster membership. You don’t need to specify the full set of servers, but you may want to specify more than one, in case of failover.

Type: list
Importance: high

src.kafka.client.id

An ID string to pass to the server when making requests. This string is used to track the source of requests. It allows a logical application name to be included in server-side request logging.

Type: string
Default: “”
Importance: low

src.kafka.request.timeout.ms

Specifies 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, or fail the request if retries are exhausted.

Type: int
Default: 30000
Valid Values: [0,…]
Importance: medium

src.kafka.retry.backoff.ms

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

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

src.kafka.connections.max.idle.ms

Specifies the amount of time (milliseconds) before idle connections are closed.

Type: long
Default: 540000
Importance: medium

src.kafka.reconnect.backoff.ms

Specifies the amount of time to wait before attempting to reconnect to a 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.

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

src.kafka.metric.reporters

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.

Type: list
Default: “”
Importance: low

src.kafka.metrics.num.samples

The number of samples maintained to compute metrics.

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

src.kafka.metrics.sample.window.ms

The window of time a metrics sample is computed over.

Type: long
Default: 30000
Valid Values: [0,…]
Importance: low

src.kafka.send.buffer.bytes

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

Type: int
Default: 131072
Valid Values: [-1,…]
Importance: medium

src.kafka.receive.buffer.bytes

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

Type: int
Default: 65536
Valid Values: [-1,…]
Importance: medium

src.kafka.timestamps.topic.replication.factor

Replication factor for the consumer timestamps topic.

Type: int
Default: 3
Importance: high

src.kafka.timestamps.topic.num.partitions

Number of partitions for the consumer timestamps topic.

Type: int
Default: 50
Importance: high

Source Kafka: Security¶

Tip

For a full description of Replicator encryption and authentication options available on various protocols, see the overview on Replicator Security.

src.kafka.security.protocol

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

Type: string
Default: PLAINTEXT
Valid Values: [PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL]
Importance: medium

src.kafka.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
Importance: medium

src.kafka.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
Importance: low

src.kafka.sasl.kerberos.min.time.before.relogin

Login thread sleep time between refresh attempts.

Type: long
Default: 60000
Importance: low

src.kafka.sasl.kerberos.kinit.cmd

Kerberos kinit command path.

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

src.kafka.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
Importance: medium

src.kafka.sasl.kerberos.ticket.renew.jitter

Percentage of random jitter added to the renewal time.

Type: double
Default: 0.05
Importance: low

src.kafka.ssl.protocol

The TLS 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 might be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities. With the default value for this configuration and ssl.enabled.protocols, clients downgrade to TLSv1.2 if the server does not support TLSv1.3. If this configuration is set to TLSv1.2, clients do 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: TLSv1.3
Importance: medium

src.kafka.ssl.provider

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

Type: string
Default: null
Importance: medium

src.kafka.ssl.enabled.protocols

The comma-separated list of protocols enabled for TLS connections. The default value is TLSv1.2,TLSv1.3 when running with Java 11 or later, TLSv1.2 otherwise. With the default value for Java 11 (TLSv1.2,TLSv1.3), Kafka clients and brokers prefer TLSv1.3 if both support it, and falls back to TLSv1.2 otherwise (assuming both support at least TLSv1.2).

Type: list
Default: TLSv1.2,TLSv1.3
Importance: medium

src.kafka.ssl.keystore.location

The location of the key store file. This is optional for client and can be used for two-way client authentication.

Type: string
Default: null
Importance: high

src.kafka.ssl.cipher.suites

A list of cipher suites. This is a named combination of authentication, encryption, MAC, and key exchange algorithms used to negotiate the security settings for a network connection using TLS. By default, all the available cipher suites are supported.

Type: list
Default: null
Importance: low

src.kafka.ssl.secure.random.implementation

The SecureRandom PRNG implementation to use for TLS cryptography operations.

Type: string
Default: null
Importance: low

src.kafka.ssl.truststore.type

The file format of the trust store file.

Type: string
Default: JKS
Importance: medium

src.kafka.ssl.keystore.type

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

Type: string
Default: JKS
Importance: medium

src.kafka.ssl.trustmanager.algorithm

The algorithm used by trust manager factory for TLS connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.

Type: string
Default: PKIX
Importance: low

src.kafka.ssl.truststore.location

The location of the trust store file.

Type: string
Default: null
Importance: high

src.kafka.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.

Type: password
Default: null
Importance: high

src.kafka.ssl.keymanager.algorithm

The algorithm used by key manager factory for TLS connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.

Type: string
Default: SunX509
Importance: low

src.kafka.ssl.key.password

The password of the private key in the key store file. This is optional for client.

Type: password
Default: null
Importance: high

src.kafka.ssl.truststore.password

The password for the trust store file.

Type: password
Default: null
Importance: high

src.kafka.ssl.endpoint.identification.algorithm

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

Type: string
Default: https
Importance: low

Source Kafka: Consumer¶

The following configuration options are properties that are specific to the Kafka consumer. These options will be combined with the src.kafka properties and forwarded to consumers that connect to the source cluster.

src.consumer.allow.auto.create.topics

Allow automatic topic creation on the broker when subscribing to or assigning a topic. A topic being subscribed to will be automatically created only if the broker allows for it using auto.create.topics.enable broker configuration. This configuration must be set to false when using brokers older than 0.11.0.

Type: boolean
Default: false
Importance: medium

Note

Normally, this config in consumers defaults to true. However, for Replicator this config internally defaults to false so as not to allow topic creation by consumers. To delete topics while Replicator is running, you can do so in one of two ways if you have topic.auto.create set to true: either, stop Replicator and delete all the topics, or set auto.create.topics.enable to false on the Kafka clusters.
Replicator does not support auto topic creation where the source topic is configured with replica placement constraints (confluent.placement.constraints). As a workaround, you can manually create the topic on the destination cluster, and disable topic.auto.create within the Replicator configuration. (See topic.auto.create under Destination Topics.)

src.consumer.interceptor.classes

A list of classes to use as interceptors. Implementing the ConsumerInterceptor interface allows you to intercept (and possibly mutate) records received by the consumer. By default, there are no interceptors.

Type: list
Default: null
Importance: low

src.consumer.fetch.max.wait.ms

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.

Type: int
Default: 500
Valid Values: [0,…]
Importance: low

src.consumer.fetch.min.bytes

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.

Type: int
Default: 1
Valid Values: [0,…]
Importance: high

src.consumer.fetch.max.bytes

The maximum amount of data the server should return for a fetch request. 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 the consumer can make progress. The maximum message size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config). Note that the consumer performs multiple fetches in parallel.

Type: int
Default: 52428800
Valid Values: [0,…]
Importance: medium

src.consumer.max.partition.fetch.bytes

The maximum amount of data per-partition the server will return. If the first message in the first non-empty partition of the fetch is larger than this limit, the message will still be returned to ensure that the consumer can make progress. The maximum message size accepted by the broker is defined via message.max.bytes (broker config) or max.message.bytes (topic config). See fetch.max.bytes for limiting the consumer request size

Type: int
Default: 1048576
Valid Values: [0,…]
Importance: high

src.consumer.max.poll.records

The maximum number of records returned in a single call to poll().

Type: int
Default: 500
Valid Values: [1,…]
Importance: medium

src.consumer.check.crcs

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.

Type: boolean
Default: true
Importance: low

Destination Topics¶

topic.rename.format

A format string for the topic name in the destination cluster, which may contain ${topic} as a placeholder for the originating topic name. For example, dc_${topic} for the topic orders will map to the destination topic name dc_orders.

Be careful of the potential for topic name collisions when configuring replicators from multiple source clusters. We typically recommend that each cluster be given a distinct prefix or suffix (as in the example above).

Type: string
Default: ${topic}
Importance: high

Tip

Starting with Confluent Platform 5.2.0, you can use Confluent Replicator to migrate schemas to another Schema Registry, which is either self-managed or on Confluent Cloud.

If you configure Confluent Replicator to use the default subject translator for schemas as follows:

schema.subject.translator.class=io.confluent.connect.replicator.schemas.DefaultSubjectTranslator

then, topic.rename.format is used to rename the subjects in the target Schema Registry during a schema migration.

For example, if the topic.rename.format is ${topic}-replica, the subject mytopic-value in the original Schema Registry would be renamed mytopic-replica-value in the “new”, target registry.

Only the schemas that use the subject name strategy TopicNameStrategy (subject name with -key or -value) will be renamed. All other subjects (which use different naming strategies) will be migrated but not renamed.

topic.auto.create

Whether to automatically create topics in the destination cluster if required.

Type: boolean
Default: true
Importance: low

Note

Replicator does not support auto topic creation where the source topic is configured with replica placement constraints (confluent.placement.constraints). As a workaround, you can manually create the topic on the destination cluster, and disable topic.auto.create within the Replicator configuration.

topic.preserve.partitions

Whether to automatically increase the number of partitions in the destination cluster to match the source cluster and ensure that messages replicated from the source cluster use the same partition in the destination cluster.

Type: boolean
Default: true
Importance: low

Note

If topic.preserve.partitions is set to false, offset.topic.commit must also be set to false. Replicator does not support offset.topic.commit=true when topic.preserve.partitions=false.
If offset.topic.commit is set to false, there won’t be any consumer groups in the source cluster.

topic.create.backoff.ms

Time to wait before retrying auto topic creation or expansion.

Type: int
Default: 120000
Valid Values: [0,…]
Importance: low

topic.config.sync

Whether to periodically sync topic configuration to the destination cluster.

Type: boolean
Default: true
Importance: low

topic.config.sync.interval.ms

How often to check for configuration changes when topic.config.sync is enabled.

Type: int
Default: 120000
Valid Values: [0,…]
Importance: low

topic.timestamp.type

The timestamp type for the topics in the destination cluster.

Type: string
Default: CreateTime
Valid Values: [CreateTime, LogAppendTime]
Importance: low

dest.topic.replication.factor

Sets the replication factor for the topic at the destination cluster.

Type: int
Default: source replication factor
Valid Values: > 0
Importance: low

Destination Kafka¶

Tip

Starting in Replicator 5.4.0, dest.kafka.* configurations are no longer mandatory. If these configurations are not supplied, their values are inferred from producer configurations in the Connect worker.

The following configuration options are common properties that are used across Kafka clients. Replicator uses these options to connect with the destination cluster (adminclient). Valid client properties that use the dest.kafka prefix will be forwarded to clients that connect to the destination cluster for admin operations.

dest.kafka.bootstrap.servers

A list of host and port pairs to use for establishing the initial connection to the destination Kafka cluster. The client will use all servers, irrespective of which servers are designated here for bootstrapping. This list only controls the initial hosts used to discover the full set of servers. This list must be in the form host1:port1,host2:port2,.... These servers are only used for the initial connection, to discover the full cluster membership. You don’t need to specify the full set of servers, but you may want to specify more than one, in case of failover.

Type: list
Importance: high

dest.kafka.client.id

An ID string to pass to the server when making requests. This string is used to track the source of requests. It allows a logical application name to be included in server-side request logging.

Type: string
Default: “”
Importance: low

dest.kafka.request.timeout.ms

Specifies 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, or fail the request if retries are exhausted.

Type: int
Default: 30000
Valid Values: [0,…]
Importance: medium

dest.kafka.retry.backoff.ms

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

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

dest.kafka.connections.max.idle.ms

Specifies the amount of time (milliseconds) before idle connections are closed.

Type: long
Default: 540000
Importance: medium

dest.kafka.reconnect.backoff.ms

Specifies the amount of time to wait before attempting to reconnect to a 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.

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

dest.kafka.metric.reporters

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.

Type: list
Default: “”
Importance: low

dest.kafka.metrics.num.samples

The number of samples maintained to compute metrics.

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

dest.kafka.metrics.sample.window.ms

The window of time a metrics sample is computed over.

Type: long
Default: 30000
Valid Values: [0,…]
Importance: low

dest.kafka.send.buffer.bytes

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

Type: int
Default: 131072
Valid Values: [-1,…]
Importance: medium

dest.kafka.receive.buffer.bytes

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

Type: int
Default: 65536
Valid Values: [-1,…]
Importance: medium

Destination Kafka: Security¶

Tip

For a full description of Replicator encryption and authentication options available on various protocols, see the overview on Replicator Security.

dest.kafka.security.protocol

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

Type: string
Default: PLAINTEXT
Valid Values: [PLAINTEXT, SSL, SASL_PLAINTEXT, SASL_SSL]
Importance: medium

dest.kafka.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
Importance: medium

dest.kafka.sasl.kerberos.ticket.renew.window.factor

Specifies the window factor of time that the login thread will sleep until the ticket is renewed. The window factor of time is computed from last refresh to ticket’s expiry.

Type: double
Default: 0.8
Importance: low

dest.kafka.sasl.kerberos.min.time.before.relogin

Login thread sleep time between refresh attempts.

Type: long
Default: 60000
Importance: low

dest.kafka.sasl.kerberos.kinit.cmd

Kerberos kinit command path.

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

dest.kafka.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
Importance: medium

dest.kafka.sasl.kerberos.ticket.renew.jitter

Percentage of random jitter added to the renewal time.

Type: double
Default: 0.05
Importance: low

dest.kafka.ssl.protocol

The TLS 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 might be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities. With the default value for this configuration and ssl.enabled.protocols, clients downgrade to TLSv1.2 if the server does not support TLSv1.3. If this configuration is set to TLSv1.2, clients do 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: TLSv1.3
Importance: medium

dest.kafka.ssl.provider

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

Type: string
Default: null
Importance: medium

dest.kafka.ssl.enabled.protocols

The comma-separated list of protocols enabled for TLS connections. The default value is TLSv1.2,TLSv1.3 when running with Java 11 or later, TLSv1.2 otherwise. With the default value for Java 11 (TLSv1.2,TLSv1.3), Kafka clients and brokers prefer TLSv1.3 if both support it, and falls back to TLSv1.2 otherwise (assuming both support at least TLSv1.2).

Type: list
Default: TLSv1.2,TLSv1.3
Importance: medium

dest.kafka.ssl.keystore.location

The location of the key store file. This is optional for client and can be used for two-way client authentication.

Type: string
Default: null
Importance: high

dest.kafka.ssl.cipher.suites

A list of cipher suites. This is a named combination of authentication, encryption, MAC, and key exchange algorithms used to negotiate the security settings for a network connection using TLS. By default, all the available cipher suites are supported.

Type: list
Default: null
Importance: low

dest.kafka.ssl.secure.random.implementation

The SecureRandom PRNG implementation to use for TLS cryptography operations.

Type: string
Default: null
Importance: low

dest.kafka.ssl.truststore.type

The file format of the trust store file.

Type: string
Default: JKS
Importance: medium

dest.kafka.ssl.keystore.type

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

Type: string
Default: JKS
Importance: medium

dest.kafka.ssl.trustmanager.algorithm

The algorithm used by trust manager factory for TLS connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.

Type: string
Default: PKIX
Importance: low

dest.kafka.ssl.truststore.location

The location of the trust store file.

Type: string
Default: null
Importance: high

dest.kafka.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.

Type: password
Default: null
Importance: high

dest.kafka.ssl.keymanager.algorithm

The algorithm used by key manager factory for TLS connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.

Type: string
Default: SunX509
Importance: low

dest.kafka.ssl.key.password

The password of the private key in the key store file. This is optional for client.

Type: password
Default: null
Importance: high

dest.kafka.ssl.truststore.password

The password for the trust store file.

Type: password
Default: null
Importance: high

dest.kafka.ssl.endpoint.identification.algorithm

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

Type: string
Default: null
Importance: low

Destination Data Conversion¶

key.converter

Converter for the key field of messages written to the destination cluster. Use io.confluent.connect.replicator.util.ByteArrayConverter if you don’t need data conversion.

Type: class
Default: inherited from worker configuration
Importance: low

value.converter

Converter for the value field of messages written to the destination cluster. Use io.confluent.connect.replicator.util.ByteArrayConverter if you don’t need data conversion.

Type: class
Default: inherited from worker configuration
Importance: low

header.converter

HeaderConverter class used to convert serialized Kafka headers to Kafka Connect headers. Currently, the default value is SimpleHeaderConverter, which outputs base64 encoded headers. To get human readable headers showing the origin cluster name, topic name, and timestamp, you must explicitly set this to the ByteArrayConverter as follows: header.converter=io.confluent.connect.replicator.util.ByteArrayConverter.

Type: class
Default: SimpleHeaderConverter
Importance: low

Consumer Offset Translation¶

Important

Offset translation is for Java consumers only; it does not work for other types of applications.

offset.translator.tasks.max

The maximum number of Replicator tasks that will perform offset translation. If -1 (the default), all tasks will perform offset translation.

Type: int
Default: -1
Importance: medium

offset.translator.tasks.separate

Whether to translate offsets in separate tasks from those performing topic replication.

Type: boolean
Default: false
Importance: medium

offset.translator.batch.period.ms

The period in milliseconds during which offset translation requests will be batched.

Type: int
Default: 60000
Importance: medium

offset.translator.batch.size

The maximum size of a batch for offset translation requests.

Type: int
Default: 2147483647 (Integer.MAX_VALUE)
Importance: medium

offset.timestamps.commit

Whether to commit internal offset timestamps for Replicator, so that it can resume properly when switching to the secondary cluster.

Type: boolean
Default: true
Importance: medium

src.kafka.timestamps.topic.replication.factor

See src.kafka.timestamps.topic.replication.factor under Source Kafka.

src.kafka.timestamps.topic.num.partitions

See src.kafka.timestamps.topic.num.partitions under Source Kafka.

provenance.header.enable

Whether to enable the use of provenance headers during replication.

Type: boolean
Default: false
Importance: medium

To learn more about this setting, see Using Provenance Headers to Prevent Duplicates or Cyclic Message Repetition. Note the requirement to explicitly set header.converter=io.confluent.connect.replicator.util.ByteArrayConverter when provenance headers are enabled, as described in that section.

Note

If Kafka messages have custom headers and are being replicated with provenance headers (provenance.header.enable=true), the consumer applications that are processing headers should skip the header with key __replicator_id. Depending on how the consumer is processing records, this may not require a code change. If the consumer is asking for a specific header, no change is required. If, however, the consumer is using toArray from the Kafka class Interface Headers to return all headers, the consumer must explicitly skip __replicator_id, otherwise, the replication will produce errors such as “could not decode JSON types ..” and “unrecognized tokens”.

Here is an example of Java code for the consumer that uses ConsumerRecord to read the header keys and skips __replicator_id:

ConsumerRecord<byte[], byte[]> record = ...
  Headers headers = record.headers();
  if (headers != null) {
    for (Header header : headers) {
      if (!"__replicator_id".equals(header.key())) {
        ... process application header...
      }
    }
  }

provenance.header.filter.overrides

Configured on a separate, temporary Replicator instance, specifies which data to exclude from normal replication filtering rules that prevent cyclic replication of messages. Semi-colon-delimited list of tuples as follows:

Regular expression for the cluster ID to match that in the provenance header
Regular expression for the topic name to match that in the provenance header
Range of timestamps

Use this parameter for disaster recovery in particular scenarios where data in the Kafka topics in the original cluster could not be fully restored. In such cases, delete the remaining data in a cluster as a starting point for recovery, then re-run Replicator across datacenters. When you re-run Replicator in this scenario, override normal filtering rules that would otherwise skip replication of previously copied data. For more information and examples, see the topic “Data Synchronization in Active-Passive Design” under “Manually Reset Consumer Offsets” in the whitepaper: Disaster Recovery for Multi-Datacenter Apache Kafka Deployments.

fetch.offset.expiry.ms

The amount of time in milliseconds after which a fetch offset request for offset translation expires and is discarded.

Type: long
Default: 600000
Importance: low

fetch.offset.retry.backoff.ms

The amount of time in milliseconds to wait before attempting to retry a failed fetch offset request during offset translation.

Type: long
Default: 100
Importance: low

Schema Translation¶

Note

These properties are only required when using the Schema translation feature of Replicator. For more information regarding this see Use Schema Registry to Migrate Schemas in Confluent Platform.

schema.registry.topic

The topic that acts as the durable log for the schema registry.

Type: string
Default: null
Importance: medium

schema.registry.url

Comma-separated list of URLs for schema registry instances that can be used to register or look up schemas.

Type: string
Default: null
Importance: high

schema.registry.max.schemas.per.subject

Maximum number of schemas to cache locally.

Type: int
Default: 1000
Importance: low

schema.registry.client.basic.auth.credentials.source

Specify how to pick the credentials for Basic Auth header. The supported values are URL, USER_INFO and SASL_INHERIT

Type: string
Default: URL
Importance: medium

schema.registry.client.basic.auth.user.info

Specify the user info for Basic Auth in the form of {username}:{password}

Type: string
Default: null
Importance: medium

schema.subject.translator.class

Translator for the schema subject, or null if no translation is to be performed. Properties with the prefix schema.subject.translator. will be passed to the configure() method of the translator.

Type: class
Default: null
Importance: low

Offset Management¶

offset.start

Specify the preference for determining where to start replication. Use connect to prefer the Connect offset if it exists, and the consumer offset otherwise. Use consumer to prefer the consumer offset if it exists, and the Connect offset otherwise. If neither the Connect offset nor the consumer offset exist, the starting offset will be the beginning of the topic.

Type: string
Default: connect
Importance: low

Note

It is recommended that you set it to the default of offset.start=connect, unless running Replicator in the bidirectional setup.

offset.topic.commit

Whether to commit Replicator’s consumer offsets to the source Kafka cluster after the messages have been written to the destination cluster. These consumer offsets can be used to easily track the lag of Replicator.

Type: boolean
Default: true
Importance: medium

Note

If topic.preserve.partitions is set to false, offset.topic.commit must also be set to false. Replicator does not support offset.topic.commit=true when topic.preserve.partitions=false.
If offset.topic.commit is set to false, there won’t be any consumer groups created by Replicator in the source cluster.

Cluster ID and Group ID¶

The parameter cluster.id is required when running Replicator as an executable. This defines a unique identifier for the cluster that is formed when several instances of Replicator Executable start with the same --cluster.id, and is a property on the executable only. The cluster.id does not have a default value; it must be specified at runtime.

Replicator executables that have the same cluster.id will automatically discover each other and form a cluster.

For non-executable deployments (using Connect workers), the parameter group.id is a unique string specified in the Connect worker that identifies the cluster group the worker belongs to. The default is connect-cluster. Distributed Worker Configuration that have the same group.id will automatically discover each other and form a cluster.

If you want more than one cluster, you must specify different IDs appropriately, depending on the deployment type:

Each cluster needs a unique cluster.id when running Replicator as an executable.
Each cluster needs a unique group.id for non-executable distributed workers.

Tip

group.id is a property on the Connect worker, not on Replicator. It is mentioned here because it serves the same purpose as cluster.id for non-executable Replicator deployments.

Confluent Platform license¶

Important

From 5.5.0 onwards, Replicator will fail immediately after the license key expires, even if Replicator is running.

Tip

For complete license information for Confluent Platform, see Confluent Platform Licenses.

confluent.topic.bootstrap.servers

A list of host/port pairs to use for establishing the initial connection to the Kafka cluster used for licensing. All servers in the cluster will be discovered from the initial connection. 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
Importance: high

confluent.topic

Name of the Kafka topic used for Confluent Platform configuration, including licensing information.

Type: string
Default: _confluent-command
Importance: low

confluent.topic.replication.factor

The replication factor for the Kafka topic used for Confluent Platform configuration, including licensing information. This is used only if the topic does not already exist, and the default of 3 is appropriate for production use. If you are using a development environment with less than 3 brokers, you must set this to the number of brokers (often 1).

Type: int
Default: 3
Importance: low

Confluent license properties¶

Note

By default, license-related properties (confluent.topic.*) are inherited from dest.kafka.* connector properties.

confluent.license

Confluent issues enterprise license keys to each subscriber. The license key is text that you can copy and paste as the value for confluent.license. A trial license allows using the connector for a 30-day trial period. A developer license allows using the connector indefinitely for single-broker development environments.

If you are a subscriber, contact Confluent Support for more information.

Type: string
Default: “”
Valid Values: Confluent Platform license
Importance: high

confluent.topic.ssl.truststore.location

The location of the trust store file.

Type: string
Default: null
Importance: high

confluent.topic.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.

Type: password
Default: null
Importance: high

confluent.topic.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
Importance: high

confluent.topic.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.

Type: password
Default: null
Importance: high

confluent.topic.ssl.key.password

The password of the private key in the key store file. This is optional for client.

Type: password
Default: null
Importance: high

confluent.topic.security.protocol

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

Type: string
Default: “PLAINTEXT”
Importance: medium

License topic configuration¶

A Confluent enterprise license is stored in the _confluent-command topic. This topic is created by default and contains the license that corresponds to the license key supplied through the confluent.license property. No public keys are stored in Kafka topics.

The following describes how the default _confluent-command topic is generated under different scenarios:

A 30-day trial license is automatically generated for the _confluent command topic if you do not add the confluent.license property or leave this property empty (for example, confluent.license=).
Adding a valid license key (for example, confluent.license=<valid-license-key>) adds a valid license in the _confluent-command topic.

Here is an example of the minimal properties for development and testing.

You can change the name of the _confluent-command topic using the confluent.topic property (for instance, if your environment has strict naming conventions). The example below shows this change and the configured Kafka bootstrap server.

confluent.topic=foo_confluent-command
confluent.topic.bootstrap.servers=localhost:9092

The example above shows the minimally required bootstrap server property that you can use for development and testing. For a production environment, you add the normal producer, consumer, and topic configuration properties to the connector properties, prefixed with confluent.topic..

License topic ACLs¶

The _confluent-command topic contains the license that corresponds to the license key supplied through the confluent.license property. It is created by default. Connectors that access this topic require the following ACLs configured:

CREATE and DESCRIBE on the resource cluster, if the connector needs to create the topic.
DESCRIBE, READ, and WRITE on the _confluent-command topic.

Important

You can also use DESCRIBE and READ without WRITE to restrict access to read-only for license topic ACLs. If a topic exists, the LicenseManager will not try to create the topic.

You can provide access either individually for each principal that will use the license or use a wildcard entry to allow all clients. The following examples show commands that you can use to configure ACLs for the resource cluster and _confluent-command topic.

Set a CREATE and DESCRIBE ACL on the resource cluster:

kafka-acls --bootstrap-server localhost:9092 --command-config adminclient-configs.conf \
--add --allow-principal User:<principal> \
--operation CREATE --operation DESCRIBE --cluster

Set a DESCRIBE, READ, and WRITE ACL on the _confluent-command topic:

kafka-acls --bootstrap-server localhost:9092 --command-config adminclient-configs.conf \
--add --allow-principal User:<principal> \
--operation DESCRIBE --operation READ --operation WRITE --topic _confluent-command

Override Default Configuration Properties¶

You can override the replication factor using confluent.topic.replication.factor. For example, when using a Kafka cluster as a destination with less than three brokers (for development and testing) you should set the confluent.topic.replication.factor property to 1.

You can override producer-specific properties by using the producer.override.* prefix (for source connectors) and consumer-specific properties by using the consumer.override.* prefix (for sink connectors).

You can use the defaults or customize the other properties as well. For example, the confluent.topic.client.id property defaults to the name of the connector with -licensing suffix. You can specify the configuration settings for brokers that require SSL or SASL for client connections using this prefix.

You cannot override the cleanup policy of a topic because the topic always has a single partition and is compacted. Also, do not specify serializers and deserializers using this prefix; they are ignored if added.