Why are Azure Resource Groups associated with a specific region?

Question

I am trying to understand why Azure Resource Groups, which are logical deployment buckets for applications built on Azure, are associated with a region when they are defined.

At first I thought it was to provide global distribution for disaster recovery or geographic redundancy, but then I realized that a single Resource Group can contain web apps in different regions, which can provide those features via Traffic Manager. I suppose that using separate Resource Groups would help better identify which resources are in which region, but other than for organizational purposes, I can't understand what the region definition for Resource Groups implies.

Answer 1

None of the other answers have mentioned that if the location that your resource group is in becomes unavailable, then you cannot update the resources in that resource group. This is because the metadata for those resources is stored in the resource group's location, so even if the resource is available, if the resource group is not then you cannot update the resource's configuration.

Here's the full quote from the MS Resource Group docs:

When you create a resource group, you need to provide a location for that resource group.

You may be wondering, "Why does a resource group need a location? And, if the resources can have different locations than the resource group, why does the resource group location matter at all?"

The resource group stores metadata about the resources. When you specify a location for the resource group, you're specifying where that metadata is stored. For compliance reasons, you may need to ensure that your data is stored in a particular region.

To ensure state consistency for the resource group, all control plane operations are routed through the resource group's location. When selecting a resource group location, we recommend that you select a location close to where your control operations originate. Typically, this location is the one closest to your current location. This routing requirement only applies to control plane operations for the resource group. It doesn't affect requests that are sent to your applications.

If a resource group's region is temporarily unavailable, you can't update resources in the resource group because the metadata is unavailable. The resources in other regions will still function as expected, but you can't update them. This condition doesn't apply to global resources like Azure Content Delivery Network, Azure DNS, Azure DNS Private Zones, Azure Traffic Manager, and Azure Front Door.

For more information about building reliable applications, see Designing reliable Azure applications.

To minimize the number of region failures that can impact your services and your ability to manage them, I recommend having your resource group be in the same region as all of its resources.

Reasons to consider using a different resource group region than what the resources use:

• For data compliance reasons.
• If you have multiple resources in different regions together in the same resource group, then you just have to pick a region for the resource group to use.

Answer 2

The main reason for specifying the location of a resource group is to specify a location for data/metadata for the deployment to be stored in... It also makes the API consistent (think of the paths in REST API calls) but the primary reason is storage during deployment.

The location of the resources in the group is independent/not related to the location of the group itself.

Answer 3

It appears there is no obvious way to determine what region a resource group is in after it has been created. This has caused me grief per the discussion here, when I ran into problems with CDN metadata conflicts. I had to start over. Now I name my resource groups with the region. e.g.: my-resourcegroup-westus

Answer 4

When creating a resource group, you need to provide a location for that resource group. You may be wondering, "Why does a resource group need a location? And, if the resources can have different locations than the resource group, why does the resource group location matter at all?" The resource group stores metadata about the resources. Therefore, when you specify a location for the resource group, you are specifying where that metadata is stored. For compliance reasons, you may need to ensure that your data is stored in a particular region.

https://learn.microsoft.com/en-us/azure/azure-resource-manager/resource-group-overview

Answer 5

Resource groups are basically for you to decide which resources in your application you want to manage together and by manage I mean you want to deploy, manage, and monitor them as a group so at a high level you do not see them as separate components.

In general in a big ecosystem, Azure resource groups are the ones that you do not see those components(resources) in them as separate entities, instead you see them as related and interdependent parts of a single entity so you put them in one Resource Group so that using the Azure Resource Group Manager tool You can deploy, update or delete all of the resources for your application in a single, coordinated operation.

You use a template for deployment and that template can work for different environments such as testing, staging and production. You can clarify billing for your organization by viewing the rolled-up costs for the entire group.

You can find more details on Azure Resource Manager here which I believe will help you better understand the idea behind the Azure Resource Groups:

https://azure.microsoft.com/en-us/documentation/articles/resource-group-overview/

Answer 6

The meta data (definition) of the Azure resource group needs to be stored somewhere. hence the location. However, resources inside a resource group are location independent and can be placed in a different region\location. Do note that dependencies between resources can exist. A Virtual machine in West Europe obviously needs a storage account in West Europe as well, but a SQL database in the same resource group can exist in West US.

Answer 7

Everything in Azure relates to a physical location/Datacenter, and ARM is no different. A little while ago, not every Datacenter supported ARM, so the reason for choosing made even more sense. Now, like any other Azure resource, the decision is for the user to make, often based on their required proximity to the end user and/or legal geographic requirements.