I am new to Spring Cloud Data Flow, and need to listen for messages on a topic from an external kafka cluster. This external kafka topic in confluent cloud would be my Source that I need to pass on to my Sink application.
I am also using kafka as my underlying message broker, which is a separate kafka instance that is deployed on kubernetes. I'm just not sure what is the best approach to connect to this external kafka instance. Is there an existing kafka Source app that I can use, or do I need to create my own Source application to connect to it? Or is it just some kind of configuration that I need to setup to get connected?
Any examples would be helpful. Thanks in advance!
Related
What are the different ways to get Kafka Cluster Audit log to GCP Logging?
Can anyone share more information on how can I achieve it?
Thank you!
Assuming you have access to the necessary topic (from what I understand the Audit topic is not stored on your own cluster), to get data out of Kafka, you need a consumer. This could be in any language.
To get data into Cloud Logging, you need to use its API.
That being said, you could use any compatible pair of Kafka clients & Cloud logging clients that you would be comfortable with.
For example, you could write or find a Kafka Connect Sink connector that wraps the Java Cloud Logging client.
Kafka Streams is good, but I have to do every configuration very manual. Instead Kafka Connect provides its API interface, which is very useful for handling the configuration, as well as Tasks, Workers, etc...
Thus, I'm thinking of using Kafka Connect for my simple data transforming service. Basically, the service will read the data from a topic and send the transformed data to another topic. In order to do that, I have to make a custom Sink Connector to send the transformed data to the kafka topic, however, it seems those interface functions aren't available in SinkConnector. If I can do it, that would be great since I can manage tasks, workers via the REST API and running the tasks under a distributed mode (multiple instances).
There are 2 options in my mind:
Figuring out how to send the message from SinkConnector to a kafka topic
Figuring out how to build a REST interface API like Kafka Connect which wraps up the Kafka Streams app
Any ideas?
Figuring out how to send the message from SinkConnector to a kafka topic
A sink connector consumes data/messages from a Kafka topic. If you want to send data to a Kafka topic you are likely talking about a source connector.
Figuring out how to build a REST interface API like Kafka Connect which wraps up the Kafka Streams app.
using the kafka-connect-archtype you can have a template to create your own Kafka connector (source or sink). In your case that you want to build some stream processing pipeline after the connector, you are mostly talking about a connector of another stream processing engine that is not Kafka-stream. There are connectors for Kafka <-> Spark, Kafka <-> Flink, ...
But you can build your using the template of kafka-connect-archtype if you want. Use the MySourceTask List<SourceRecord> poll() method or the MySinkTask put(Collection<SinkRecord> records) method to process the records as stream. They extend the org.apache.kafka.connect.[source.SourceTask|sink.SinkTask] from Kafka connect.
a REST interface API like Kafka Connect which wraps up the Kafka Streams app
This is exactly what KsqlDB allows you to do
Outside of creating streams and tables with SQL queries, it offers a REST API as well as can interact with Connect endpoints (or embed a Connect worker itself)
https://docs.ksqldb.io/en/latest/concepts/connectors/
My pipeline is:
Kerberized Kafka --> Logstash (hosted on a different server) --> Splunk.
Can I replace the Logstash component with Kafka Connect?
Could you point me to a resource/guide where I can use kerberized Kafka as a source for my Kafka connect (which is hosted separately)?
From the documentation, what I understood is that if Kafka Connect is hosted on the same cluster as that of Kafka, that's quite possible. But I don't have that option right now, as our Kafka cluster is multi-tenant and hence not approved for additional processes on the cluster.
Kerberos keytabs aren't commonly machine/JVM specific, so yes, Kafka Connect should be able to be configured very similarly to Logstash since both are JVM processes using native Kafka protocol.
You shouldn't run Connect on the brokers anyway
If you can't add Kafka Connect to an existing Kafka cluster, you will have to spin up a separate Kafka Connect (Cluster or standalone).
I've written about it here: enter link description here
We are currently on HDF (Hortonworks Dataflow) 3.3.1 which bundles Kafka 2.0.0 and are trying to use Kafka Connect in distributed mode to launch a Google Cloud PubSub Sink connector.
We are planning on sending back some metadata into a Kafka Topic and need to integrate a Kafka producer into the flush() function of the Sink task java code.
Would this have a negative impact on the process where Kafka Connect commits back the offsets to Kafka (as we would be adding a overhead of running a Kafka producer before the flush).
Also, how does Kafka Connect get the Bootstrap servers list from the configuration when it is not specified in the Connector Properties for either the sink or the source? I need to use the same Bootstrap server list to start the producer.
Currently I am changing the config for the sink connector, adding bootstrap server list as a property and parsing it in the Java code for the connector. I would like to use bootstrap server list from the Kafka Connect worker properties if that is possible.
Kindly help on this.
Thanks in advance.
need to integrate a Kafka producer into the flush() function of the Sink task java code
There is no producer instance exposed in the SinkTask API...
Would this have a negative impact on the process where Kafka Connect commits back the offsets to Kafka (as we would be adding a overhead of running a Kafka producer before the flush).
I mean, you can add whatever code you want. As far as negative impacts go, that's up to you to benchmark on your own infrastructure. Obviously adding more blocking code makes the other processes slower overall
how does Kafka Connect get the Bootstrap servers list from the configuration when it is not specified in the Connector Properties for either the sink or the source?
Sinks and sources are not workers. Look at connect-distributed.properties
I would like to use bootstrap server list from the Kafka Connect worker properties if that is possible
It's not possible. Adding extra properties to the sink/source configs are the only way. (Feel free to make a Kafka JIRA requesting such a feature of exposing the worker configs, though)
I'm to build a Java based Kafka streaming application that will listen to a topic X continiously, fetch data, perform some basic cleansing and write to a Oracle database. The kafka cluster is outside my domain and have no ability to deploy any code or configurations in it.
What is the best way to design such a solution? I came across Kafka Streams but was confused as to if it can be used for 'Topic > Process > Topic' scenarios?
I came accross Kafka Streams but was confused as to if it can be used for 'Topic > Process > Topic' scenarios?
Absolutely.
For example, excluding the "process" step, it's two lines outside of the configuration setup.
final StreamsBuilder builder = new StreamsBuilder();
builder.stream("streams-plaintext-input").to("streams-pipe-output");
This code is straight from the documentation
If you want to write to any database, you should first check if there is a Kafka Connect plugin to do that for you. Kafka Streams shouldn't really be used to read/write from/to external systems outside of Kafka, as it is latency-sensitive.
In your case, the JDBC Sink Connector would work well.
The kafka cluster is outside my domain and have no ability to deploy any code or configurations in it.
Using either solution above, you don't need to, but you will need some machine with Java installed to run a continous Kafka Streams application and/or Kafka Connect worker.