VM Role
-GreatControl VM Level, To migrate existing application
-hosted onwindows image
VM Role is PaaS
The first thing to note about the VM role in its current formis that it is not considered infrastructure as aservice.
This makes sense when you consider the Azure Fabric—the Fabric Controller can bring down any role instance at anytime, for many good reasons,including hardware failure, Host OS updates, oreven to gain hardware efficiencies in the data center. In addition, the nodes sit behind a round-robin load balancer. This is whatmakes Azure strong as a PaaS provider.
Since the nodes sit behind a round-robin load balancer, In order tomaintain the Azure SLA,You will need at least two instances of your roledeployed
This has several architectural impacts, including the following:
• State management. Because there are two instances runningbehind a roundrobin
load balancer, you will need to store runtime stateinformation outside the
VM. Windows Azure Caching is a good candidate for this.
File management: Files will also need to be maintainedoutside the VM. Because
the load balancers route requests in a round-robin fashion,the file systems on
each compute instance will quickly become dissimilar andfragmented unless files
are stored centrally. If the files are read-only files, thenWindows Azure Drives are
a great solution. Otherwise, consider using Azure blob storage. Because if has read/write, Azure Drives is durable but only for one instance, it cannot maintain all Drives to be sync.
VM Role Use Case
-One would be anapplication that requires many other products to be installed to run correctly
-take time
-not support insilence mode
-Long runningapplication installations
-Error-proneapplication installations
-Applicationinstallations requiring manual interaction
So, what this means today is that VM role is notwell suited to running stateful server applications.
Obviously, you wouldn’t want to install ActiveDirectory to a VM role, but applications like SQL Server
and Oracle are also not good candidates at thispoint.
At a high level, there are the following threesteps to deploying a VM to Windows Azure:
1. Create a base image in Hyper-V.
2. Apply sysprep.exe.
3. Upload to Windows Azure.
Features Missing in VM Role compare with Web/Worker Role
-Automated,Consistent OS servicing
Lifecycle of VM Role
-Build VMImage
-WindowsServer 2008 R2, create Base.VHD
-CustomizeVHD
-Installsoftware
-WindowsPatches
-CustomerApplication
-KeyPiece:Windows Azure Integration Component (communicate with fabric controler)
-SaveDiff.VHD
-Uploadto Blob Storage
-Installto VM Instance
-CreateService; Test Locally
-Upload VMImage
-DeployService
-MaintainService
-UpgradService
The operating system that is installed on the base VHD canbe one of the following:
Windows Server 2008 R2 Enterprise (English only)
Windows Server 2008 R2 Standard (English only)
Deployment Pattern
-HighPerformance Computing
-e.g.:MediaEncoding Software
-Migratingexisting application
-e.g.:LegacyJava/Tomcat Web app + Windows Azure Connect + On-premise SQL Server