Taking Control In The Cloud

Arun Sirpal advises you to enjoy the change in control when moving to Azure:

The key for me has been to “embrace the change”. I have come from a traditional DBA background, backups, consistency checks, server level configuration at the heart of things. Yes, I no longer care about SQL backups and things of that nature when operating within Azure but I have different tasks and to think about.

Sceptical? Please read on.

Do read on.

Analyzing Twitter Data With Storm In HDInsight

Nischal S shows how to configure an HDInsight cluster to process tweets, followed by loading them into a Power BI dashboard:

When we need to process streams of real-time data, Storm is a great contender. Examples of streaming data are the number of consumer clicks and navigations on a website, IIS or user logs, IoT data, and social network information. In all these scenarios, we use real-time data processing. Apache Storm can process real-time unbounded streams of data.

The term “unbounded” defines streams of data with no start or end. Here, the processing of data is continuous and in real-time. Twitter is a good example. Twitter data is continuous, has no start or end time, and is provided in real-time by millions of Twitter users around the world.

Storm wouldn’t rank in my top three technologies for doing this, but it certainly does the job.

Generating U-SQL Extract Scripts From Visual Studio

Yanan Cai shows a GUI for creating U-SQL EXTRACT scripts via Azure Data Lake Tools for Visual Studio:

One of U-SQL’s core capabilities is to be able to schematize unstructured data on the fly without having to create a metadata object for it. This capability is provided by the EXTRACT expression that will invoke either a user-defined extractor or built-in extractor to process the input file or set of files specified in the FROM clause and produces a rowset whose schema is specified in the EXTRACT clause.

While using the build-in extractor to schema semi-structured data, like data in .csv file, the schema definition in U-SQL is slow and error prone, especially for the .csv file contains hundreds of columns.

Recently, we released a new feature in the latest version of Azure Data Lake Tools for Visual Studio to help you generate this U-SQL EXTRACT statement automatically.

Click through for an example as well as a video showing the process.

Cloudera Director And AWS Spot Instances

David Han shows off some new features in Cloudera Director 2.5 to help when building Hadoop clusters on AWS spot price instances:

You can configure Spot instances in Cloudera Director’s instance templates. These instance templates contain a flag indicating whether Spot instances should be used, as well as a field specifying the bid price for those instances.

Each instance group in the cluster template includes a field that indicates the minimum number of instances required in that group for the cluster to be considered successful. Cloudera Director will continue with bootstrapping or growing a cluster if the minimum count for each instance group is satisfied. Spot instances should not be used for instance groups that are required for the normal operation of the cluster, such as HDFS DataNodes. Instance groups configured to use Spot instances should set their minimum number to zero with the expectation that the instances may not be provisioned due to the Spot bid price being lower than the Spot price.

If you’re able to take advantage of spot instances, you can end up saving a pretty good amount of money.

Creating A WSFC Witness On Azure

Jim Donahoe shows how to create a cloud witness for a Windows cluster using Azure:

Well, that is easy to fix, right?  Let’s just spin up a VM in Azure, and host the FSW on that machine.  Problem solved!  Technically yes, that is a viable option.  But, let’s consider the cost of that scenario in the breakdown below:

  1. VM with OS licensed and Disk space allocated for FSW
  2. NSG/Firewall to protect said resource from outside 
  3. VNET

Also, you have to figure in the man hours in configuring all of those things(Let’s say 4 hours total.  Insert your hourly rate here:  Rate x 4 = Setup fee for VM in Azure

Now, here is where Cloud Witness saves the day!  The Cloud Witness WSFC Quorum type will utilize BLOB Storage in Azure to act as the point of arbitration.  Not sure what that means?

There’s a good walkthrough, but it does look quite easy to do, and a simple blob is going to be a lot cheaper than a VM.

Using Hive LLAP On ElasticMapReduce

Jigar Mistry shows how to configure and use Hive LLAP on AWS’s ElasticMapReduce:

With many options available in the market (Presto, Spark SQL, etc.) for doing interactive SQL  over data that is stored in Amazon S3 and HDFS, there are several reasons why using Hive and LLAP might be a good choice:

  • For those who are heavily invested in the Hive ecosystem and have external BI tools that connect to Hive over JDBC/ODBC connections, LLAP plugs in to their existing architecture without a steep learning curve.

  • It’s compatible with existing Hive SQL and other Hive tools, like HiveServer2, and JDBC drivers for Hive.

  • It has native support for security features with authentication and authorization (SQL standards-based authorization) using HiveServer2.

  • LLAP daemons are aware about of the columns and records that are being processed which enables you to enforce fine-grained access control.

  • It can use Hive’s vectorization capabilities to speed up queries, and Hive has better support for Parquet file format when vectorization is enabled.

  • It can take advantage of a number of Hive optimizations like merging multiple small files for query results, automatically determining the number of reducers for joins and groupbys, etc.

  • It’s optional and modular so it can be turned on or off depending on the compute and resource requirements of the cluster. This lets you to run other YARN applications concurrently without reserving a cluster specifically for LLAP.

Read on for more details, including the bootstrap action you need to take and how to use LLAP once you have it configured.

Going Back From The Cloud

Arun Sirpal notes that you can take a cloud database back to on-premises:

The Challenge: I am going to write about a way to move from Azure SQL Database (Platform as a service) back to a local SQL Server. I did encounter errors on the way but more importantly I have written how to avoid/solve them.

Another key point I made sure that there were no connections to the database when doing the below as I didn’t want in-flight data movement whilst doing it. If you can’t do this, then you should create a copy of the database and work from that.

It’s not a trivial operation, but Arun does walk us through the steps.

More On S3Guard

Aaron Fabbri describes how S3Guard works:

Although Apache Hadoop has support for using Amazon Simple Storage Service (S3) as a Hadoop filesystem, S3 behaves different than HDFS.  One of the key differences is in the level of consistency provided by the underlying filesystem.  Unlike HDFS, S3 is an eventually consistent filesystem.  This means that changes made to files on S3 may not be visible for some period of time.

Many Hadoop components, however, depend on HDFS consistency for correctness. While S3 usually appears to “work” with Hadoop, there are a number of failures that do sometimes occur due to inconsistency:

  • FileNotFoundExceptions. Processes that write data to a directory and then list that directory may fail when the data they wrote is not visible in the listing.  This is a big problem with Spark, for example.

  • Flaky test runs that “usually” work. For example, our root directory integration tests for Hadoop’s S3A connector occasionally fail due to eventual consistency. This is due to assertions about the directory contents failing. These failures occur more frequently when we run tests in parallel, increasing stress on the S3 service and making delayed visibility more common.

  • Missing data that is silently dropped. Multi-step Hadoop jobs that depend on output of previous jobs may silently omit some data. This omission happens when a job chooses which files to consume based on a directory listing, which may not include recently-written items.

Worth reading if you’re looking at using S3 to store data for Hadoop.  Also check out an earlier post on the topic.

Auto-Install Docker And SQL Tools On Linux

Andrew Pruski has a script on GitHub:

So I’ve created a repository on GitHub that pulls together the code from Docker to install the Community Edition and the code from Microsoft to install the SQL command line tools.

The steps it performs are: –

  • Installs the Docker Community Edition

  • Installs the SQL Server command line tools

  • Pulls the latest SQL Server on Linux image from the Docker Hub

Read on for more details and some limitations.

Web Editor For Azure Analysis Services

James Serra shows off a preview of the Azure Analysis Services web designer for tabular models:

Microsoft has released a preview of the Azure Analysis Services web designer.  This is a browser-based experience that will allow developers to start creating and managing Azure Analysis Services (AAS) semantic models quickly and easily.  SQL Server Data Tools (SSDT) and SQL Server Management Studio (SSMS) will still be the primary tools for development, but this new designer gives you another option for creating a new model or to do things such as adding a new measure to a development or production AAS model.

A highly requested feature is that you can import a Power BI Desktop file (.pbix) into an Analysis Services database.  And once imported you can reverse engineer to Visual Studio.  Note for PBIX import only Azure SQL Database, Azure SQL Data warehouse, Oracle, and Teradata are supported at this time and Direct Query models are not yet supported for import (Microsoft will be adding new connection types for import every month).

Read on for more details.

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