At April 16 Microsoft announced that Windows Azure Virtual Machines is general available (GA). This means the service is fully supported by Microsoft and can be used for production purposes. The service was in preview mode since June 2012.
Azure Virtual Machines is an Infrastructure as a Service service model. That means the consumer of the service is responsible for managing the operating system and all software running on that operating system. So far Windows Azure was a Platform as a Service only service model. Developers could use the platform to create and execute applications using a fixed set of tooling like SharePoint, SQL server or .NET. If the preferred tool was not made available by Microsoft it could not be used. The consumer was not responsible for managing the operating system.
That changes with Windows Azure Virtual Machines. Customers can now create a guest VM running a selected number of supported operating systems. Now they can run any application they want on that virtual machine. Besides provisioning using an Azure management portal, virtual machines can also be provisioned using System Center Orchestrator, using PowerShell and using System Center App Controller. Also VHD (VHDX not supported on Azure) virtual disks can be created on-premises on Hyper-V and then uploaded to Azure.
Also via the VM Depot many images are available of Linux distributions preloaded with a lot of different applications. Just a few examples are Drupal, Joomla!, Ruby Stack and WordPress.
To learn more about Azure Infrastructure Services see this short video.
Since the general availability of Windows Azure Virtual Machines some things are improved compared to the Preview:
1. Two additional sizes for virtual machines are added. Available now are 7 sizes including two Monster VM’s. Those 2 monster VM’s have 4 or 8 cores and 28 GB or 56 GB of internal memory.
2. Additional images are available. Images (or templates) contain a pre-installed operating system and software like SQL Server or SharePoint. Supported operating systems are Windows Server 2008, Windows Server 2012, SUSE Linux Enterprise Server, Ubuntu, OpenSUSE and Openlogic CentOS
3. Costs for some of the Azure services are reduced with 21 to 30 percent.
Microsoft today also announced they will follow price reductions of Amazon. So when Amazon lowers prices, Microsoft immediately will do so too.
What not has changed is the availability in the SLA. The SLA states that Microsoft agrees to deliver connectivity to the virtual machine during 99,95% of the billing month. To meet the SLA the customer needs to have at least 2 instances of a virtual machine running which are part of the same availability set.
Suppose a customer want to runs a legacy application which does not have availability features in the application and does not support clustering. The VM the application is running on is a single point of failure. When the virtual machine goes down (Microsoft performing scheduled maintenance on Azure involving downtime for the host, host hardware issues, networking issues) Microsoft does not violate the SLA even when 99,95% is not reached. Simply because there is no SLA for a single instance virtual machine.
An Azure Availability set ensures that virtual machines instances are not running in the same fault domain. A fault domain is the same host or the same rack. An availability set makes sure members (virtual machines) of that group never run on the same single point of failure. It is the same as anti-affinity rules in Hyper-V/SCVMM or vCenter Server.
Much more on Azure availability sets can be read here in a post titled Windows Azure Host Updates: Why, When, and How
The Service Level Agreement for virtual machines can be downloaded here.
- “Maximum Connectivity Minutes” is the total accumulated minutes during a billing month for all Internet facing Virtual Machines that have two or more instances deployed in the same Availability Set. Maximum Connectivity Minutes is measured from when at least two Virtual Machines in the same Availability Set have both been started resultant from action initiated by Customer to the time Customer has initiated an action that would result in stopping or deleting the Virtual Machines.
Below a nice infographic of Windows Azure. The full version can be seen here at dotnetsolutions.co.uk