An Azure Lexicon for Working with Virtual Machines in Microsoft Azure
When working with the Microsoft Azure Public cloud, you'll quickly discover that it has its own set of defined terms. There are several key components associated with an Azure virtual machine such as Azure Region, Affinity Group, Cloud Service, Azure virtual network or Azure vNet in short, and storage account.
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You need to have an understanding of these components, which will cover in this article, when creating a virtual machine in Azure. Several of these components optional, but a few are mandatory as we'll explain.
Azure Region and Virtual Machine Size: Azure Region is the name of the Azure data center where hundreds of Hyper-V clusters are running. Azure provides virtual machine with different sizes.
The minimum virtual machine size that you can deploy in Azure is A0, which has a maximum memory of 768 MB. The maximum size of a virtual machine is G5, which provides 16 cores and 224 GB memory.
However, not all virtual machine sizes are available to all the regions. There are 17 Azure regions where Azure datacenters are located. A0 through A7 VM instances are supported in all 17 Azure regions, but A8 and A9 VM instances are only supported in the Eastern US, North Central US, South Central US, Western US, North Europe, West Europe and Japan EST Azure regions.
Similarly, D-series virtual machine sizes are supported in all regions except US Gov Iowa, US Gov Virginia and Brazil South Azure regions. Finally, G-series virtual machines are supported only for East US 2 and West US Azure regions. When creating a virtual machine in Azure, you must select an Azure Region or an Affinity group that holds the Azure region name where the virtual machine will be stored.
Affinity Group: An Affinity Group holds the Microsoft datacenter region name. When you create a virtual machine in Azure, you are asked to select the Affinity Group where the virtual machine contents will be stored.
Note that you can create an Affinity Group only via the manage.windowsazure.com portal. The new Azure portal at https://portal.azure.com does not support the creation of an Affinity Group.
To create an Affinity Group, you need to go to the Settings page in Azure, click Affinity Groups tab and then click on "Add" button to bring the "Create Affinity Group" Window as shown in the screenshot below.
Use of Affinity Groups is no longer recommended. This article has more information on the change in recommendation.
Azure Virtual Network: Virtual machines that you create on Azure will receive IP addresses from a DHCP server that is being managed by Azure internally. There is a possibility that you might want to deploy a group of virtual machines in Azure that will need to be on different IP subnets.
For example, you might want to deploy ten virtual machines in Azure and you need to ensure two of the ten virtual machines reside on a 10.0.0.0 IP subnet and the remaining virtual machines are on IP subnet 10.32.0.0. To allow virtual machines to be on different IP subnets, you will need to create an Azure virtual network and then define the address space in the Azure virtual network as shown in the screenshot below.
Once you have created an Azure virtual network, select the virtual network when creating an Azure virtual machine. This process ensures that virtual machines will receive IP addresses from the Azure virtual network as well as the address space that was selected when creating the virtual machines.
Storage Account: When you create virtual machines in Azure, the virtual machine creation wizard asks you to select a storage account that will be used to store VM files such as VM configuration and virtual hard disk files. While Azure can create a storage account automatically when creating a virtual machine, creating a storage account beforehand will help you manage things properly.
To create a storage account, click on New > Data Services > Storage > Quick Create and then specify the details such as storage account name, Affinity Group or Azure region it should be created in as shown in the screenshot below.
As you can see in the above screenshot, we created a storage account with the name "vmstorageaccount2012r2" and assigned it to the AffinityGroup1 Affinity Group. We could have also selected the Azure region name, but since we have created an Affinity Group that already has the name of an Azure region where virtual machines are going to reside, we selected Affinity Group.
It is important to note that if you need to attach virtual machines to an Azure vNet, you must select an Azure Region name when creating a storage account rather than selecting an Affinity Group. Check out this article for a more detailed explanation of this requirement.
Nirmal Sharma is a MCSEx3, MCITP and Microsoft MVP in Directory Services. He has specialized in Microsoft Technologies since 1994 and has followed the progression of Microsoft Operating System and software. In his spare time, he likes to help others and share some of his knowledge by writing tips and articles on various sites and contributing to Solution IDs for www.Dynamic-SpotAction.com. Nirmal can be reached at firstname.lastname@example.org.
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