docs: Update for topic name configuration (#1909)

* docs: Update for topic name configuration

* Move kafka ssl documentation from faq to kafka config page.

docs/faq.md

@@ -112,11 +112,3 @@ Supported data sources are listed [here](https://github.com/linkedin/datahub/tre
 
 ## How is metadata ingested in DataHub? Is it real-time?
 You can call the [rest.li](https://github.com/linkedin/rest.li) API to ingest metadata in DataHub directly instead of using Kafka event. Metadata ingestion is real-time if you're updating via rest.li API. It's near real-time in the case of Kafka events due to the asynchronous nature of Kafka processing.
-
-## Does Kafka support SSL? If so, how?
-
-Yes. We are using the Spring Boot framework to start our apps, including setting up Kafka. You can [use environment variables to set system properties](https://docs.spring.io/spring-boot/docs/current/reference/html/spring-boot-features.html#boot-features-external-config-relaxed-binding-from-environment-variables), including [Kafka properties](https://docs.spring.io/spring-boot/docs/current/reference/html/appendix-application-properties.html#integration-properties). From there you can set your SSL configuration for Kafka.
-
-If Schema Registry is configured to use security (SSL), then you also need to set the following config: https://docs.confluent.io/current/kafka/encryption.html#encryption-ssl-schema-registry.
-
-> **Note** In the logs you might see something like `The configuration 'kafkastore.ssl.truststore.password' was supplied but isn't a known config.` The configuration is not a configuration required for the producer. These WARN message can be safely ignored. Each of Datahub services are passed a full set of configuration but may not require all the configurations that are passed to them. These warn messages indicate that the service was passed a configuration that is not relevant to it and can be safely ignored.

docs/how/kafka-config.md

@@ -19,3 +19,33 @@ DataHub components that connect to Kafka are currently:
 - mce-consumer-job
 - mae-consumer-job
 - gms
+- Various ingestion example apps
+
+## Configuring Topic Names
+
+By default, ingestion relies upon the `MetadataChangeEvent_v4`, `MetadataAuditEvent_v4`, and `FailedMetadataChangeEvent` kafka topics by default for
+[metadata events](https://github.com/linkedin/datahub/blob/master/docs/what/mxe.md.
+
+We've included environment variables to customize the name each of these topics, if your company or organization has naming rules for your topics.
+
+- `METADATA_CHANGE_EVENT_NAME`: The name of the metadata change event topic.
+- `METADATA_AUDIT_EVENT_NAME`: The name of the metadata audit event topic.
+- `FAILED_METADATA_CHANGE_EVENT_NAME`: The name of the failed metadata change event topic.
+
+Please ensure that these environment variables are set consistently throughout your ecosystem. DataHub has a few different applications running which communicate with Kafka (see above).
+
+## SSL
+
+We are using the Spring Boot framework to start our apps, including setting up Kafka. You can
+[use environment variables to set system properties](https://docs.spring.io/spring-boot/docs/current/reference/html/spring-boot-features.html#boot-features-external-config-relaxed-binding-from-environment-variables),
+including [Kafka properties](https://docs.spring.io/spring-boot/docs/current/reference/html/appendix-application-properties.html#integration-properties).
+From there you can set your SSL configuration for Kafka.
+
+If Schema Registry is configured to use security (SSL), then you also need to set 
+[this config](https://docs.confluent.io/current/kafka/encryption.html#encryption-ssl-schema-registry).
+
+> **Note** In the logs you might see something like
+> `The configuration 'kafkastore.ssl.truststore.password' was supplied but isn't a known config.` The configuration is
+> not a configuration required for the producer. These WARN message can be safely ignored. Each of Datahub services are
+> passed a full set of configuration but may not require all the configurations that are passed to them. These warn
+> messages indicate that the service was passed a configuration that is not relevant to it and can be safely ignored.