Scala + Hadoop + HDInsight

Emmanouil Gkatziouras shows that you can run a Hadoop job written in Scala on Azure’s HDInsight:

Previously, we set up a Scala application in order to execute a simple word count on Hadoop.

What comes next is uploading our application to HDInsight. So, we shall proceed in creating a Hadoop cluster on HDInsight.

Read the whole thing, but the upshot is that Scala apps build jar files just like Java would, so there’s nothing special about running them.

Azure Elastic Pools

Derik Hammer explains what Azure SQL Database Elastic Pools do:

Azure SQL Database Elastic Pools are a mechanism for grouping your Azure SQL Databases together into a shared resource pool. Imagine for a moment that you had a physical server on premise. On that server, you have a single SQL Server instance and a single database. This example is similar to how Azure SQL Database works. You have a fixed amount of resources and you pay for those resources, even when you are not using them.

An Elastic Pool is analogous to that same server and instance, instead you add several databases to the instance. The databases will share the same resource pool which can be cheaper than paying for separate sets of resources, as long as your databases’ peak usage times do not align with each other.

Read on to see how you can potentially save money on databases using an elastic pool instead of spinning up the databases independently.

Azure Managed Disks

Dave Bermingham explains what Azure Managed Disks are and why you might want to use them:

What’s Managed Disks you ask? Well, just on February 8th Corey Sanders announced the GA of Managed Disks. You can read all about Managed Disks here. https://azure.microsoft.com/en-us/services/managed-disks/

The reason why Managed Disks would have helped in this outage is that by leveraging an Availability Set combined with Managed Disks you ensure that each of the instances in your Availability Set are connected to a different “Storage scale unit”. So in this particular case, only one of your cluster nodes would have failed, leaving the remaining nodes to take over the workload.

Prior to Managed Disks being available (anything deployed before 2/8/2016), there was no way to ensure that the storage attached to your servers resided on different Storage scale units. Sure, you could use different storage accounts for each instances, but in reality that did not guarantee that those Storage Accounts provisioned storage on different Storage scale units.

Read on for more details.

Kinesis vs SQS

Kevin Sookocheff compares and contrasts Amazon’s Kinesis and SQS offerings:

Complicated Producer and Consumer Libraries

For maximum performance, Kinesis requires deploying producer and consumer libraries alongside your application. As a producer, you deploy a C++ binary with a Java interface for reading and writing data records to a Kinesis stream. As a consumer, you deploy a Java application that can communicate with other programming languages through an interface built on top of standard in and standard out. In either of these cases, adding new producers or consumers to a Kinesis stream presents some investment in development and maintenance.

Click through for the full comparison and figuring out where each fits.

U-SQL Updates

Michael Rys has a large batch of updates to Azure Data Lake and the U-SQL language:

Here are the March 9 2017 Updates for Azure Data Lake U-SQL and Developer Tooling!

The main take away is that we continue the deprecation of items that we changed during the preview phase and introduce a lot of new capabilities including PIVOT/UNPIVOT more catalog sharing and much more!

There’s a pretty hefty list of updates to check out.

R On Athena

Gopal Wunnava shows how to run R scripts using Amazon Athena as a data source:

Next, you’ll practice interactively querying Athena from R for analytics and visualization. For this purpose, you’ll use GDELT, a publicly available dataset hosted on S3.

Create a table in Athena from R using the GDELT dataset. This step can also be performed from the AWS management console as illustrated in the blog post “Amazon Athena – Interactive SQL Queries for Data in Amazon S3.”

This is an interesting use case for Athena.

Coalescing In DocumentDB

Melissa Coates shows how to use the null coalesce operator in DocumentDB to provide default values for missing attributes:

This is a quick post to share how we can use the coalesce operator in Azure DocumentDB (which is a schema-free, NoSQL database) to handle situations when the data structure varies from file to file. Varying data structure is a common issue in big data and analytics projects. A schema-free database like DocumentDB allows us to ingest and store the data with varying structures without a lot of upfront effort. However, accommodating these varying data structures is challenging later when we want to analyze the data. When querying the data (think Schema on Read here), I do need to impose a consistent structure on the data to perform analytics.

Read the whole thing.

Biml And ADF, Part 2

Meagan Longoria builds Azure Data Factory pipelines using BimlScript:

The great thing about Biml is that I can use it as much or as little as I feel is helpful. That T-SQL statement to get column lists could have been Biml, but it didn’t have to be. The client can maintain and enhance these pipelines with or without Biml as they see fit. There is no vendor lock-in here. Just as with Biml-generated SSIS projects, there is no difference between a hand-written ADF solution and a Biml-generated ADF solution, other than the Biml-generated solution is probably more consistent.

And have I mentioned the time savings? There is a reason why Varigence gives out shirts that say “It’s Monday and I’m done for the week.”

Click through for the script.

U-SQL Custom Python Libraries

Saveen Reddy explains how to build a custom Python library and use it with U-SQL:

First, let’s talk about “zipimport”. Thanks to the adoption of PEP 273 – Python had the ability to import modules from ZIP files since Python 2.3. This ability is called “zipimport” and is a built-in feature of the Python’s existing import statement. Read the zipimport documentation now.

To review the basics.

  • You create a module (a .py file, etc.)

  • ZIP up the module into a .zip file

  • Add the path to the .zip file to sys.path

  • Then import the module

Read on for the step-by-step process.

HDInsight Basics: Nodes

Abdullah Al Mahmood explains some of the basics of Azure HDInsight, including what Hadoop means by nodes:

HDInsight clusters consist of several virtual machines (nodes) serving different purposes. The most common architecture of an HDInsight cluster is – two head nodes, one or more worker nodes, and three zookeeper nodes.

Head nodes: Hadoop services are installed and run on head nodes. There are two head nodes to ensure high availability by allowing master services and components to continue to run on the secondary node in the event of a failure on the primary. Both head nodes are active and running within the cluster simultaneously. Some services, such as HDFS or YARN, are only ‘active’ on one head node at any given time (and ‘standby’ on the other head node). Other services such as HiveServer2 or Hive Metastore are active on both head nodes at the same time. There are services like Application Timeline Server (ATS) and Job History Server (JHS) which are installed on both head nodes but should run only on the head node where Ambari server is running. If these components sound unfamiliar, please revisit the article on Hadoop ecosystem in HDInsight.

Read on to see the other classes of nodes HDInsight uses.

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