Can’t Delete an Azure Resource Group

Recently, I hit a wall. I wasn’t able to delete my Azure Resource Groups and got quite frustrated… I’m writing this post, with hopes that you may save some time, frustration and energy with your ongoing challenge.

Copying a Blob Using Azure PowerShell

On regular occasions, I need to move blobs from one storage account to another. And there are a couple of ways that we can do this. The first is to download the blob and upload it to a new location. In most scenarios, this is not what we want. This post demonstrates how to create an Azure Storage Blob Copy job and how to monitor its progress.

The Challenge

As developers, we deal with lots of complexity, and this is a good thing. It forces us to be creative, and sometimes to go beyond our known universe to overcome challenges.

Microsoft Azure is designed to help us make the right choices. It imposes performance targets through a multitude of mechanisms like throttling and quotas. One of which, I’m sure you have come to know, is that we cannot scale a Cloud Service to zero instances. Let’s stop for a moment and think about this limitation for a second. How would you creatively overcome this challenge?

Scaling an FTP Ingestion Service

Making an FTP Ingestion Service Highly Available (HA) can be a challenge. On Azure, we can take advantage of the Microsoft Azure Traffic Manager to direct users to the closest FTP Server. In this specific scenario, we assume that all FTP Servers are configured the same way and that users only have write access. When a document is uploaded over FTP, it is moved to a Microsoft Azure Storage Account that is used as persistent storage.

Uploading Content to Azure Blobs

I use Azure Blobs on a regular basis. They’re generally really useful and help me through some tough situations. Working with Blobs is simple. You can interact with them using Visual Studio, third-party tools, REST and even through PowerShell.

The following PowerShell command demonstrates how I upload content to Azure Storage.

Set-BlobContent -StorageAccountName 'scaleupdowndemopkgs' `
                -StorageContainer 'packages' `
                -FilePath 'C:\Service\cloud_package.cspkg' `
                -BlobName 'extra_small_vm_cloud_package.cspkg'

Meet DocumentDB

These days I’m all about automation. As most of us are focused on Python, C# JavaScipt and Node I’m taking a different approach to Azure DocumentDB. This experiment’s goal is to facilitate the creation and seeding of DocumentDBs with very little effort from JSON documents stored an Azure Blob Storage container.

Azure DocumentDB is a NoSQL document database service designed from the ground up to natively support JSON and JavaScript directly inside the database engine. It’s the right solution for web and mobile applications when predictable throughput, low latency, and flexible query are key. Microsoft consumer applications like OneNote already use DocumentDB in production to support millions of users.

Preventing Jobs From Running Simultaneously on Multiple Role Instances

There are times where we need to schedule maintenance jobs to maintain our Azure Cloud Services. Usually, it requires us to design our systems with an extra Role in order to host these jobs.

Adding this extra Role (Extra Small VM) costs about $178.56 a year!

But don’t worry! There’s another way to schedule jobs. You can use Blob leasing to control the number of concurrent execution of each job. You can also use Blob leasing to help distribute the jobs over multiple Role instances.

Don’t be Fooled, Blob Lease Management is Tricky Business

Leasing Blobs on Azure Blob Storage Service establishes a lock for write and delete operations. The lock duration can be 15 to 60 seconds, or can be infinite.

Personally prefer to lease a blob for a short period of time, which I renew until I decide to release the lease. To some, it might seem more convenient to lease a blob indefinitely and to release it when they’re done. But on Azure, Role instances can be taken offline for a number of reasons like maintenance updates. Blobs that are indefinitely leased can eventually be leased by a process that no longer exists.

Granted that leasing a blob for a short period of time and renewing the lease costs more, but it’s essential for highly scalable Azure Cloud Services. In situations where a process that had the original lease is prevented from completing its task, an other Role can take over.

Renewing blob leases requires extra work, but it’s really worth it when you think about it.

Create Single Use URIs to Protect Your Resources!

Finding the problem, of controlling access to specific resources for a certain amount of time and for a certain amount of downloads, to be quite interesting. So I decided to design a solution that would take advantage of the services made available by the Windows Azure platform.

The Challenge

Create single use URIs that invalidate after 15 minutes.

Why?

Companies that sell digital products often try to limit the number of downloads per purchase. Consequently, discouraging customers from sharing their download links becomes a priority. By creating public URIs constrained by a time to live and by a limited number downloads, can help accomplish this goal.

The Concept

Building on the Valet Key Pattern explored in “Keep Your Privates Private!” I used Shared Access Signatures to create a time to live for all public URIs. Then to control access to the actual resources I created a REST service using Web API, which tracks individual access to each URI using the Windows Azure Table Storage Service.

Save Money by Setting Cache-Control on Windows Azure Blobs

On Windows Azure everything including bandwidth has a price tag, but don’t be alarmed. The price tag isn’t that steep.

The important thing to remember on the cloud, is that we’re talking about economies of scale. This also means, that the cost of operation grows along with the scale and reach of your application.

Setting Cache-Control on publicly accessible Windows Azure Blobs can help reduce bandwidth by preventing consumers from having to continuously download resources. Additionally, it will greatly contribute to creating a more responsive end-user experience.

Cache-Control allows you to specify a relative amount of time to cache data after it was received. It’s mostly recommended when you need control over how caching is done.