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.

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

Enabling Kafka Security

You can configure the SDC RPC to Kafka origin to connect securely to Kafka through SSL/TLS, Kerberos, or both.

Enabling SSL/TLS

Perform the following steps to enable the SDC RPC to Kafka origin to use SSL/TLS to connect to Kafka.

To use SSL/TLS to connect, first make sure Kafka is configured for SSL/TLS as described in the Kafka documentation.
On the General tab of the stage, set the Stage Library property to the appropriate Apache Kafka version.
On the Kafka tab, add the security.protocol Kafka configuration property and set it to SSL.
Then add and configure the following SSL Kafka properties:
- ssl.truststore.location
- ssl.truststore.password
When the Kafka broker requires client authentication - when the ssl.client.auth broker property is set to "required" - add and configure the following properties:
- ssl.keystore.location
- ssl.keystore.password
- ssl.key.password
Some brokers might require adding the following properties as well:
- ssl.enabled.protocols
- ssl.truststore.type
- ssl.keystore.type
For details about these properties, see the Kafka documentation.

For example, the following properties allow the stage to use SSL/TLS to connect to Kafka with client authentication:

Enabling Kerberos (SASL)

When you use Kerberos authentication, Data Collector uses the Kerberos principal and keytab to connect to Kafka. Perform the following steps to enable the SDC RPC to Kafka origin to use Kerberos to connect to Kafka.

To use Kerberos, first make sure Kafka is configured for Kerberos as described in the Kafka documentation.
Make sure that Kerberos authentication is enabled for Data Collector, as described in Kerberos Authentication.
Add the Java Authentication and Authorization Service (JAAS) configuration properties required for Kafka clients based on your installation and authentication type:
- RPM, tarball, or Cloudera Manager installation without LDAP authentication - If Data Collector does not use LDAP authentication, create a separate JAAS configuration file on the Data Collector machine. Add the following KafkaClient login section to the file:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="<keytab path>"
    principal="<principal name>/<host name>@<realm>";
};
```
  For example:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="/etc/security/keytabs/sdc.keytab"
    principal="sdc/sdc-01.streamsets.net@EXAMPLE.COM";
};
```
  Then modify the SDC_JAVA_OPTS environment variable to include the following option that defines the path to the JAAS configuration file:
```
-Djava.security.auth.login.config=<JAAS config path>
```
  Modify environment variables using the method required by your installation type.
- RPM or tarball installation with LDAP authentication - If LDAP authentication is enabled in an RPM or tarball installation, add the properties to the JAAS configuration file used by Data Collector - the $SDC_CONF/ldap-login.conf file. Add the following KafkaClient login section to the end of the ldap-login.conf file:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="<keytab path>"
    principal="<principal name>/<host name>@<realm>";
};
```
  For example:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="/etc/security/keytabs/sdc.keytab"
    principal="sdc/sdc-01.streamsets.net@EXAMPLE.COM";
};
```
- Cloudera Manager installation with LDAP authentication - If LDAP authentication is enabled in a Cloudera Manager installation, enable the LDAP Config File Substitutions (ldap.login.file.allow.substitutions) property for the StreamSets service in Cloudera Manager.
  If the Use Safety Valve to Edit LDAP Information (use.ldap.login.file) property is enabled and LDAP authentication is configured in the Data Collector Advanced Configuration Snippet (Safety Valve) for ldap-login.conf field, then add the JAAS configuration properties to the same ldap-login.conf safety valve.
  
  If LDAP authentication is configured through the LDAP properties rather than the ldap-login.conf safety value, add the JAAS configuration properties to the Data Collector Advanced Configuration Snippet (Safety Valve) for generated-ldap-login-append.conf field.
  
  Add the following KafkaClient login section to the appropriate field as follows:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="_KEYTAB_PATH"
    principal="<principal name>/_HOST@<realm>";
};
```
  For example:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="_KEYTAB_PATH"
    principal="sdc/_HOST@EXAMPLE.COM";
};
```
  Cloudera Manager generates the appropriate keytab path and host name.
On the General tab of the stage, set the Stage Library property to the appropriate Apache Kafka version.
On the Kafka tab, add the security.protocol Kafka configuration property, and set it to SASL_PLAINTEXT.
Then, add the sasl.kerberos.service.name configuration property, and set it to kafka.

For example, the following Kafka properties enable connecting to Kafka with Kerberos:

Enabling SSL/TLS and Kerberos

You can enable the SDC RPC to Kafka origin to use SSL/TLS and Kerberos to connect to Kafka.

To use SSL/TLS and Kerberos, combine the required steps to enable each and set the security.protocol property as follows:

Make sure Kafka is configured to use SSL/TLS and Kerberos (SASL) as described in the following Kafka documentation:
- http://kafka.apache.org/documentation.html#security_ssl
- http://kafka.apache.org/documentation.html#security_sasl
Make sure that Kerberos authentication is enabled for Data Collector, as described in Kerberos Authentication.
Add the Java Authentication and Authorization Service (JAAS) configuration properties required for Kafka clients based on your installation and authentication type:
- RPM, tarball, or Cloudera Manager installation without LDAP authentication - If Data Collector does not use LDAP authentication, create a separate JAAS configuration file on the Data Collector machine. Add the following KafkaClient login section to the file:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="<keytab path>"
    principal="<principal name>/<host name>@<realm>";
};
```
  For example:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="/etc/security/keytabs/sdc.keytab"
    principal="sdc/sdc-01.streamsets.net@EXAMPLE.COM";
};
```
  Then modify the SDC_JAVA_OPTS environment variable to include the following option that defines the path to the JAAS configuration file:
```
-Djava.security.auth.login.config=<JAAS config path>
```
  Modify environment variables using the method required by your installation type.
- RPM or tarball installation with LDAP authentication - If LDAP authentication is enabled in an RPM or tarball installation, add the properties to the JAAS configuration file used by Data Collector - the $SDC_CONF/ldap-login.conf file. Add the following KafkaClient login section to the end of the ldap-login.conf file:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="<keytab path>"
    principal="<principal name>/<host name>@<realm>";
};
```
  For example:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="/etc/security/keytabs/sdc.keytab"
    principal="sdc/sdc-01.streamsets.net@EXAMPLE.COM";
};
```
- Cloudera Manager installation with LDAP authentication - If LDAP authentication is enabled in a Cloudera Manager installation, enable the LDAP Config File Substitutions (ldap.login.file.allow.substitutions) property for the StreamSets service in Cloudera Manager.
  If the Use Safety Valve to Edit LDAP Information (use.ldap.login.file) property is enabled and LDAP authentication is configured in the Data Collector Advanced Configuration Snippet (Safety Valve) for ldap-login.conf field, then add the JAAS configuration properties to the same ldap-login.conf safety valve.
  
  If LDAP authentication is configured through the LDAP properties rather than the ldap-login.conf safety value, add the JAAS configuration properties to the Data Collector Advanced Configuration Snippet (Safety Valve) for generated-ldap-login-append.conf field.
  
  Add the following KafkaClient login section to the appropriate field as follows:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="_KEYTAB_PATH"
    principal="<principal name>/_HOST@<realm>";
};
```
  For example:
```
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    keyTab="_KEYTAB_PATH"
    principal="sdc/_HOST@EXAMPLE.COM";
};
```
  Cloudera Manager generates the appropriate keytab path and host name.
On the General tab of the stage, set the Stage Library property to the appropriate Apache Kafka version.
On the Kafka tab, add the security.protocol property and set it to SASL_SSL.
Then, add the sasl.kerberos.service.name configuration property, and set it to kafka.
Then add and configure the following SSL Kafka properties:
- ssl.truststore.location
- ssl.truststore.password
When the Kafka broker requires client authentication - when the ssl.client.auth broker property is set to "required" - add and configure the following properties:
- ssl.keystore.location
- ssl.keystore.password
- ssl.key.password
Some brokers might require adding the following properties as well:
- ssl.enabled.protocols
- ssl.truststore.type
- ssl.keystore.type
For details about these properties, see the Kafka documentation.

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.

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.

On the Kafka tab, configure the following properties:

Kafka Property	Description
Broker URI	Connection string for the Kafka broker. Use the following format: `<host>:<port>`. To ensure a connection, enter a comma-separated list of additional broker URIs.
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. For information about enabling secure connections to Kafka, see Enabling Kafka Security.

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.

To use SSL/TLS, click the TLS tab and configure the following properties:

TLS Property	Description
Use TLS	Enables the use of TLS.
Keystore File	Path to the 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	The algorithm used to manage the keystore. Default is SunX509.
Use Default Protocols	Determines the transport layer security (TLS) protocol to use. The default protocol is TLSv1.2. To use a different protocol, clear this option.
Transport Protocols	The 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.