SDC RPC to Kafka (Deprecated)

The SDC RPC to Kafka origin reads data from one or more SDC RPC destinations and writes it immediately to Kafka. Use the SDC RPC to Kafka origin in an SDC RPC destination pipeline. However, the SDC RPC to Kafka origin is now deprecated and will be removed in a future release. We recommend using the SDC RPC origin.

Use the SDC RPC to Kafka origin when you have multiple SDC RPC origin pipelines with data that you want to write to Kafka without additional processing.

Like the SDC RPC origin, the SDC RPC to Kafka origin reads data from an SDC RPC destination in another pipeline. However, the SDC RPC to Kafka origin is optimized to write data from multiple pipelines directly to Kafka. When you use this origin, you cannot perform additional processing before writing to Kafka.

Here is an example of the recommended architecture for using the SDC RPC to Kafka origin:

When you configure the SDC RPC to Kafka origin, you define the port that the origin listens to for data, the SDC RPC ID, the maximum number of concurrent requests, and maximum batch request size. You can also configure SSL/TLS properties, including default transport protocols and cipher suites.

You also need to configure connection information for Kafka, including the broker URI, topic to write to, and maximum message size. You can add Kafka configuration properties and enable Kafka security as needed.

For more information about SDC RPC pipelines, see SDC RPC Pipeline Overview.

Pipeline Configuration

When you use an SDC RPC to Kafka origin in a pipeline, connect the origin to a Trash destination.

The SDC RPC to Kafka origin writes records directly to Kafka. The origin does not pass records to its output port, so you cannot perform additional processing or write the data to other destination systems.

However, since a pipeline requires a destination, you should connect the origin to the Trash destination to satisfy pipeline validation requirements.

A pipeline with the SDC RPC to Kafka origin should look like this:

Concurrent Requests

You can specify the maximum number of requests the SDC RPC to Kafka origin handles at one time.

An SDC RPC destination in an origin pipeline sends a request to the SDC RPC to Kafka origin when it wants to pass a batch of data to the origin. If you have one origin pipeline passing data to the SDC RPC to Kafka origin, you can set the maximum number of concurrent requests to 1 because the destination processes one batch of data at a time.

Typically, you would have more than one pipeline passing data to this origin. In this case, you should assess the number of origin pipelines, the expected output of the pipelines, and the resources of the Data Collector machine, and then tune the property as needed to improve pipeline performance.

For example, if you have 100 origin pipelines passing data to the SDC RPC to Kafka origin, but the pipelines produce data slowly, you can set the maximum to 20 to prevent these pipelines from using too much of the Data Collector resources during spikes in volume. Or, if the Data Collector has no resource issues and you want it to process data as quickly as possible, you can set the maximum to 90 or 100. Note that the SDC RPC destination also has advanced properties for retry and back off periods that can be used help tune performance.

Batch Request Size, Kafka Message Size, and Kafka Configuration

Configure the SDC RPC to Kafka maximum batch request size and Kafka message size properties in relationship to each other and to the maximum message size configured in Kafka.

The Max Batch Request Size (MB) property determines the maximum size of the batch of data that the origin accepts from each SDC RPC destination. Upon receiving a batch of data, the origin immediately writes the data to Kafka.

To promote peak performance, the origin writes as many records as possible into a single Kafka message. The Kafka Max Message Size (KB) property determines the maximum size of the message that it creates.

Important: The maximum message size specified in the origin must be smaller than the maximum message size configured in Kafka. By default, the maximum message size in a Kafka cluster is 1 MB, as defined by the message.max.bytes property. If the origin receives a message greater than the maximum message size, it fails to process the batch, and the destination that provided the batch processes it based on the error record handling configured for the destination.

For example, say the origin uses the default 100 MB for the maximum batch request size and the default 900 KB for the maximum message size, and Kafka uses the 1 MB default for message.max.bytes.

When the origin requests a batch of data, it receives up to 100 MB of data at a time. When the origin writes to Kafka it groups records into as few messages as possible, including up to 900 KB of records in each message. Since the message size is less than the Kafka 1 MB requirement, the origin successfully writes all messages to Kafka.

If a record is larger than the 900 KB maximum message size, the origin generates an error and does not write the record - or the batch that includes the record - to Kafka. The SDC RPC destination that provided the batch with the oversized record processes the batch based on stage error record handling.

Additional Kafka Properties

You can add custom Kafka configuration properties to the SDC RPC to Kafka origin.

When you add a Kafka configuration property, enter the exact property name and the value. The stage does not validate the property names or values.

Several properties are defined by default, you can edit or remove the properties as necessary.

Note: Because the stage uses several configuration properties, it ignores user-defined values for the following properties:
  • key.serializer.class
  • metadata.broker.list
  • partitioner.class
  • producer.type
  • serializer.class

Kafka Security

You can configure the SDC RPC to Kafka origin to connect securely to Kafka through SSL/TLS, Kerberos, or both. For more information about the methods and details on how to configure each method, see Security in Kafka Stages.

Configuring an SDC RPC to Kafka Origin

Configure an SDC RPC to Kafka origin to write data from multiple SDC RPC destinations directly to Kafka.

  1. In the Properties panel, on the General tab, configure the following properties:
    General Property Description
    Name Stage name.
    Description Optional description.
    Stage Library Library version that you want to use.
    On Record Error Error record handling for the stage:
    • Discard - Discards the record.
    • Send to Error - Sends the record to the pipeline for error handling.
    • Stop Pipeline - Stops the pipeline. Not valid for cluster pipelines.
  2. On the Kafka tab, configure the following properties:
    Kafka Property Description
    Broker URI Comma-separated list of connection strings for the Kafka brokers. Use the following format for each broker: <host>:<port>.

    To ensure a pipeline can connect to Kafka in case a specified broker goes down, list as many brokers as possible.
    Topic Kafka topic to read.
    Max Message Size (KB) Maximum size of the message to write to Kafka.
    Warning: Must be smaller than the maximum message size configured in Kafka.

    Default is 900 KB.

    Kafka Configuration

    Additional Kafka configuration properties to use. Using simple or bulk edit mode, click the Add icon to add properties. Define the Kafka property name and value.

    Use the property names and values as expected by Kafka.
    Kafka Message Key Passes message key values stored in a record header attribute to Kafka as message keys.

    Enter an expression that specifies the attribute where the message keys are stored.

    To pass string message keys stored in an attribute, use:
    ${record:attribute('<message key attribute name>'}
    To pass Avro message keys stored in an attribute, use:
    ${avro:decode(record:attribute('avroKeySchema'),base64:decodeBytes(record:attribute('<messsage key attribute name')))}

    For more information, about working with Kafka message keys, see Kafka Message Keys.
  3. On the Security tab, configure the security properties to enable the stage to securely connect to Kafka.

    For information about the security options and additional steps required to enable security, see Security in Kafka Stages.

  4. On the RPC tab, configure the following properties:
    SDC RPC Property Description
    RPC Listening Port Port number to listen to for data. Must match one of the port numbers associated with the SDC RPC destination that provides the data.
    Note: No other pipelines or processes can already be bound to the listening port. The listening port can be used only by a single pipeline.
    Max Concurrent Requests Maximum number of concurrent requests allowed at one time.
    RPC ID User-defined ID. Must match the RPC ID defined in the SDC RPC destination.
    Max Batch Request Size (MB) Maximum amount of data to be requested and processed at one time.

    Default is 100 MB.
  5. To use SSL/TLS, click the TLS tab and configure the following properties:
    TLS Property Description
    Use TLS Enables the use of TLS.
    Use Remote Keystore Enables loading the contents of the keystore from a remote credential store or from values entered in the stage properties. For more information, see Remote Keystore and Truststore.
    Private Key Private key used in the remote keystore. Enter a credential function that returns the key or enter the contents of the key.
    Certificate Chain Each PEM certificate used in the remote keystore. Enter a credential function that returns the certificate or enter the contents of the certificate.

    Using simple or bulk edit mode, click the Add icon to add additional certificates.
    Keystore File Path to the local keystore file. Enter an absolute path to the file or a path relative to the Data Collector resources directory: $SDC_RESOURCES.

    For more information about environment variables, see Data Collector Environment Configuration.

    By default, no keystore is used.

    Keystore Type Type of keystore to use. Use one of the following types:
    • Java Keystore File (JKS)
    • PKCS #12 (p12 file)

    Default is Java Keystore File (JKS).

    Keystore Password Password to the keystore file. A password is optional, but recommended.
    Tip: To secure sensitive information such as passwords, you can use runtime resources or credential stores.
    Keystore Key Algorithm Algorithm to manage the keystore.

    Default is SunX509.
    Use Default Protocols Uses the default TLSv1.2 transport layer security (TLS) protocol. To use a different protocol, clear this option.
    Transport Protocols TLS protocols to use. To use a protocol other than the default TLSv1.2, click the Add icon and enter the protocol name. You can use simple or bulk edit mode to add protocols.
    Note: Older protocols are not as secure as TLSv1.2.
    Use Default Cipher Suites Uses a default cipher suite for the SSL/TLS handshake. To use a different cipher suite, clear this option.
    Cipher Suites Cipher suites to use. To use a cipher suite that is not a part of the default set, click the Add icon and enter the name of the cipher suite. You can use simple or bulk edit mode to add cipher suites.

    Enter the Java Secure Socket Extension (JSSE) name for the additional cipher suites that you want to use.