Hooking SQL Server to Kafka

Niels Berglund has an interesting scenario for us:

We see how the procedure in Code Snippet 2 takes relevant gameplay details and inserts them into the dbo.tb_GamePlay table.

In our scenario, we want to stream the individual gameplay events, but we cannot alter the services which generate the gameplay. We instead decide to generate the event from the database using, as we mentioned above, the SQL Server Extensibility Framework.

Click through for the scenario in depth and how to use Java to tie together SQL Server and Kafka.

Notebooks in Azure Databricks

Brad Llewellyn takes us through Azure Databricks notebooks:

Azure Databricks Notebooks support four programming languages, Python, Scala, SQL and R.  However, selecting a language in this drop-down doesn’t limit us to only using that language.  Instead, it makes the default language of the notebook.  Every code block in the notebook is run independently and we can manually specify the language for each code block.

Before we get to the actually coding, we need to attach our new notebook to an existing cluster.  As we said, Notebooks are nothing more than an interface for interactive code.  The processing is all done on the underlying cluster.

Read on to learn how Databricks uses the notebook metaphor heavily in how you interact with it.

Reading and Writing CSV Files with spark-dotnet

Ed Elliott continues a series on Spark for .NET:

How do you read and write CSV files using the dotnet driver for Apache Spark?

I have a runnable example here:
https://github.com/GoEddie/dotnet-spark-examples

Specifcally:
https://github.com/GoEddie/dotnet-spark-examples/tree/master/examples/split-csv

The quoted links will take you straight to the code, but click through to see Ed’s commentary.

How .NET Code Talks to Spark

Ed Elliott has a great diagram showing how user-written .NET code communicates with Spark over the Java VM:

4. Spark-dotnet Java driver listens on tcp port
The spark-dotnet Java driver listens on a TCP socket. This socket is used to communicate between the Java VM and the dotnet code, the dotnet code doesn’t run in the Java VM but is in a separate process communitcating with the Java VM via that TCP postrt. The year is 2019, we serialize and deserialize data all the time and don’t even know it, hell notepad probably even does it.

It’s serialization & deserialization as well as TCP sockets all the way down.

Cloudera and 100% Open Source Software

Alex Woodie notes a change at Cloudera:

The old Cloudera developed and distributed its Hadoop stack using a mix of open source and proprietary methods and licenses. But the new Cloudera will be 100% open source, just like Hortonworks, its one-time Hadoop rival that it acquired in January. But will developing its data platform completely in the open differentiate it from cloud competitors?

In a blog post published yesterday under the title “Our Commitment to Open Source Software,” Cloudera executives Charles Zedlewski and Arun Murthy laid out the company’s new plan to develop and distribute everything in the open.

This was one of the big reasons I preferred Hortonworks over Cloudera when they were separate companies: Hortonworks had this model. Hopefully it leads Cloudera to success.

Kafka Docker on Kubernetes

Bill Ward gives us a step-by-step set of instructions for installing Kafka Docker on Kubernetes:

In this ultimate guide I will give you a simple step-by-step tutorial on installing Kafka Docker on Kubernetes. This post includes a complete video walk-through.

There has been a lot of interest lately about deploying Kafka to a Kubernetes cluster. If you are wanting to take the deep dive yourself then you found the right article. Now that we have Kafka Docker, deploying a Kafka cluster to Kubernetes is a snap.

This makes it even easier to get started with Kafka in a development environment.

Spark and dotnet in a Single Container

Ed Elliott shows how you can combine Spark and .NET Core in a single Docker container:

This is quite new syntax in docker and you need at least docker 17.05 (client and daemon), after the images “FROM blah” you can specify a name “core” in this case, then later you can copy from the first image to the second using “–from=” on the “COPY” command.

In this dockerfile I have added Spark 2.4.3 and the default environment variables we need to get spark running, if you grab this dockerfile and run “docker build -t dotnet-spark .” you should get an images you can then run which includes the dependencies for dotnet as well as spark.

Ed includes all of the scripts needed to test this out, too.

Feeding IoT Data into Delta Lake

Saeed Barghi shows how you can stream sensor data from Azure IoT Hub into Databricks Delta Lake:

IoT devices produce a lot of data very fast. Capturing data from all those devices, which could be at millions, and managing them is the very first step in building a successful and effective IoT platform.

Like any other data solution, an IoT data platform could be built on-premise or on cloud. I’m a huge fan of cloud based solutions specially PaaS offerings. After doing a little bit of research I decided to go with Azure since it has the most comprehensive and easy to use set of service offerings when it comes to IoT and they are reasonably priced. In this post, I am going to show how to build the architecture displayed in the diagram below: connect your devices to Azure IoT Hub and then ingest records into Databricks Delta Lake as they stream in using Spark Streaming.

Click through for the instructions.

Copying Cassandra Data to HDFS

Landon Robinson shows how you can use Spark to extract data from Cassandra and move it into HDFS:

Cassandra is a great open-source solution for accessing data at web scale, thanks in no small part to its low-latency performance. And if you’re a power user of Cassandra, there’s a high probability you’ll want to analyze the data it contains to create reports, apply machine learning, or just do some good old fashioned digging.

However, Cassandra can prove difficult to use as an analytical warehouse, especially if you’re using it to serve data in production around the clock. But one approach you can take is quite simple: copy the data to Hadoop (HDFS).

Read on to learn how.

Troubleshooting Kafka Listeners

Robin Moffatt has some tips for configuring listeners in Kafka:

Apache Kafka® is a distributed system. Data is read from and written to the leader for a given partition, which could be on any of the brokers in a cluster. When a client (producer/consumer) starts, it will request metadata about which broker is the leader for a partition—and it can do this from anybroker. The metadata returned will include the endpoints available for the Leader broker for that partition, and the client will then use those endpoints to connect to the broker to read/write data as required.

It’s these endpoints that cause people trouble. On a single machine, running bare metal (no VMs, no Docker), everything might be the hostname (or just localhost), and it’s easy. But once you move into more complex networking setups and multiple nodes, you have to pay more attention to it.

Click through for more tips.

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