Moving a Service to Microsoft Azure

Having written about lifting and shifting a Console Application, I decided to mirror the scenario and describe how a similar method can be used to lift and shift a Windows Service to Microsoft Azure.

Every time I dig a little deeper into Azure, I’m amazed at how much there is to know. Having done a few projects with Cloud Services in the past, I thought it would be interesting to see if it was possible to lift and shift a Windows Service into an Azure Worker Role.

Lift and Shift: The action of moving a workload to a new environment, without altering the application’s code.

Opening Ports on Cloud Services

There are scenarios that warrants us to open ports of the Windows Firewall. Imagine an application that coordinates work across many compute nodes. The workload coordinator needs to know and manage each compute node.

The diagram above, depicts a Virtual Machine that has direct access to instances of a Cloud Service without going through a Load Balancer. Both the Virtual Machine and Cloud Service are deployed to a Virtual Network on Microsoft Azure. Using Internal Endpoints in this scenario, would not yield the desired configuration. Endpoints are defined at the Cloud Service boundary and are IP addresses belong to the Data Center’s Network Address Space. Therefore, In order to allow the Virtual Machine to communicate over specific ports to individual Cloud Service instances, we need to use PowerShell and a Startup Task to configure the Windows Firewall.

Configuring Internal Endpoints

There are many scenarios where Internal Endpoints make sense. Imagine a web application that needs to communicate with a middle tier. The communication between both Cloud Services does not need to leave Microsoft Azure networks. The diagram above depicts a scenario where a Web Role has access to a middle tier Cloud Service without going through the public Internet.

Role instances running in a Cloud Service on Microsoft Azure communicate through internal and external connections that vary depending on the type of communication that is needed. An internal endpoint can connect by using a protocol of HTTP, TCP or UDP.

The configuration of an Internal Endpoint is done through the Service Definition. Below is the template used to describe what can be done in terms of Endpoint configurations. 

Deploying a Cloud Service to a VNet

In a recent post about Microsoft Azure Virtual Networks, I made the recommendation that Cloud Services should be deployed to Microsoft Azure Virtual Networks. The driving factor behind this recommendation comes from my personal real-world experience, where I learned the hard way, that moving a deployed Cloud Service to a Virtual Network meant downtime…

Scaling Azure Cloud Services

When we build applications on the cloud, we usually favor scaling-out over scaling-up. Consequently, scaling in and out is supported out of the box on Microsoft Azure. On rare occasions, there is a business need to scale-up during peak hours and to scale-down for the quiet hours. This blog post will show you how to achieve this with the help of Microsoft Azure Automation and with PowerShell.

Keep in mind, that scaling up and down requires us to be creative.

Moving to Microsoft Azure

Every time I dig a little deeper into Azure, I’m amazed at how much there is to know. Having done a few projects with Cloud Services in the past, I thought it would be interesting to see if it was possible to lift and shift a Console Application into an Azure Worker Role.

Lift and Shift: The action of moving a workload to a new environment, without altering the application’s code.

Releasing Memory Pressure

Traditionally, in .NET applications we adjust the Garbage Collector to operate in server mode by modifying the App.config or Web.config files. However, Worker Roles work differently because your code is actually hosted by the WaWorkerHost.exe process. So you must modify the WaWorkerHost.exe.config file instead of app.config and web.config.

This article covers the Worker Role. However, the same concepts and techniques may be used to change the Web Roles mode by changing WaWebHost.exe.config instead of WaWorkerHost.exe.config.

WaWorkerHost.exe.config is in %approot%\base\x64

What is ServerGC & Why is it Important?

The Server Garbage Collection process allows us to reclaims objects that are no longer being used, clears memory, and makes it available for future allocations. In contrast to the Work Station Garbage Collector mode, the Server Garbage Collection mode aggressively releases memory and can prevent your roles from running out of memory due to memory bloat.

Reducing memory bloat allows us to increased density, which typically reduces overall operational costs in a pay for what you consume environment. Furthermore, Background Server Garbage Collection can increase performance.

Conditions for a Garbage Collection Include

• The system has low physical memory.
• The memory that is used by allocated objects on the managed heap surpasses an acceptable threshold. This threshold is continuously adjusted as the process runs.
• The GC.Collect method is called. In almost all cases, you do not have to call this method, because the garbage collector runs continuously. This method is primarily used for unique situations and testing.

Busy… Starting Role… Repeat

So you deployed a Cloud Service and it’s status is stuck on “Busy (Starting role… Sites were deployed.)” By now you’ve probably checked the SDK assembly versions, checked that your Cloud Service runs in the Azure Emulator and probably everything else that you could think of. So what’s next?

In August 2013 Kevin Williamson published an awesome blog series titled Windows Azure PaaS Compute Diagnostics Data. It contains a wealth of priceless information that ended my 24 hour debug session.

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.

Why is The New Windows Azure Cache Service Important?

What is it?

Windows Azure Cache is a distributed, in-memory, scalable solution that can be used to build highly scalable and responsive applications by providing super-fast access to data. A cache created using the Cache Service is accessible from applications within Windows Azure running on Windows Azure Web Sites, Web & Worker Roles and Virtual Machines.

Why is it Important?

On September 3rd 2013, Microsoft announced a new Windows Azure Cache Service. This is actually quite interesting for projects that requires a Highly Available (HA) Cache. It allows you to create a Cache Cluster using the management portal. This means that all infrastructure maintenance and resource management is Microsoft’s responsibility.