Enterprise-scale FAQ

This article answers frequently asked questions about enterprise-scale architecture.

For FAQs about implementing enterprise-scale architecture, see Enterprise-scale implementation FAQ.

What is the Azure landing zone accelerator?

The Azure landing zone accelerator is an Azure portal-based deployment experience. It deploys an opinionated implementation based on the Azure landing zone conceptual architecture.

What is the Azure landing zone conceptual architecture?

The Azure landing zone conceptual architecture represents scale and maturity decisions. It's based on lessons learned and feedback from customers who have adopted Azure as part of their digital estate. This conceptual architecture can help your organization set a direction for designing and implementing a landing zone.

What does a landing zone map to in Azure in the context of enterprise-scale architecture?

From an enterprise-scale point of view, landing zones are individual Azure subscriptions.

What does policy-driven governance mean, and how does it work?

Policy-driven governance is one of the key design principles of enterprise-scale architecture.

Policy-driven governance means using Azure Policy to reduce the time you need for common and repeated operational tasks across your Azure tenant. Use many of the Azure Policy effects, such as Append, Deny, DeployIfNotExists, and Modify, to prevent non-compliance by either restricting non-compliant resources (as defined by the policy definition) from being created or updated or by deploying resources or modifying settings of a resource creation or update request to make them compliant. Some effects, such as Audit, Disabled, and AuditIfNotExists, don't prevent or take action; they only audit and report on non-compliance.

Some examples of policy-driven governance are:

  • Deny effect: Prevents subnets from being created or updated to have no Network Security Groups associated with them.

  • DeployIfNotExists effect: A new subscription (landing zone) is created and placed into a management group within your enterprise-scale deployment. Azure Policy ensures that Microsoft Defender for Cloud (formerly known as Azure Security Center) is enabled on the subscription. It also configures the diagnostic settings for Activity Log to send logs to the Log Analytics workspace in the Management subscription.

    Instead of repeating code or manual activities when a new subscription is created, the DeployIfNotExists policy definition automatically deploys and configures them for you.

What if we cannot or are not yet ready to utilize DeployIfNotExists (DINE) policies?

We have a dedicated page that walks through the various phases and options you have to either "disable" DINE policies or use our 3 phase approach to adopt them over time within your environment.

See the guidance Adopting policy driven guardrails

Should we use Azure Policy to deploy workloads?

In short, no. Use Azure Policy to control, govern, and keep your workloads and landing zones compliant. It isn't designed to deploy entire workloads and other tooling. Use the Azure portal or infrastructure-as-code offerings (ARM Templates, Bicep, Terraform) to deploy and manage your workload and get the autonomy you need.

What if we already have resources in our landing zones and later assign an Azure Policy definition that includes them in its scope?

Review the following documentation sections:

How do we handle "dev/test/production" workload landing zones in enterprise-scale architecture?

Note

This is for workload landing zones only. For testing and environment segregation for the enterprise-scale platform itself, review the testing approach for enterprise-scale.

If an application or service workload requires segregation of "dev/test/production" landing zones, use a separate subscription for each landing zone in the workload. It's important to work with the application or service workload owners to determine if separate subscriptions is the best way for them to build, manage, operate, and deliver their workload. It shouldn't be mandatory for all workloads.

A good example is a workload that uses Azure App Service. When you use Azure App Service, a best practice is to use deployment slots to help you manage changes and updates to the web app. However, this feature can only be used on the same app on an App Service Plan, which can only live within a single subscription. By mandating that your application or service workload owners use separate subscriptions for "dev/test/production", you might make their deployment lifecycle harder to manage. In this example, a single subscription for the application or service workload might be the best fit by using Azure role-based access control (RBAC) with Privileged Identity Management at the Resource Group scope for increased security.

We suggest working with each application or service workload team (landing zone owners) to understand their requirements. Then you can provide subscriptions based on their requirements and plans. You might also decide to designate "product lines" for different types of workloads so that you can build subscription creation processes and tooling based on common requirements from application or service workload teams.

What about our management group hierarchy?

With enterprise-scale architecture, you want to avoid complicated and volatile management group hierarchies that require constant amendment, don't scale efficiently, and don't add value. That's why in enterprise-scale architecture, management groups are workload archetype-aligned. For more information, see Management group and subscription organization.

Archetype-aligned means that management groups are only created for differing workload archetypes. For example, in the conceptual architecture, the "landing zones" management group has "corp" and "online" child management groups. These child management groups align with distinct archetype patterns for the workloads they hold, focused around hybrid connectivity (VPN/ExpressRoute) requirements (internal only vs. public-facing applications/services). However, all environments ("dev/test/production"), whether split across separate subscriptions or in a single subscription, are held within the same single management group ("Corp" or "Online") depending on its archetype and requirements.

The following equation helps to highlight why management groups per environment and/or per workload doesn't scale well: (N apps) x (N+3) = Total management groups

So, if you have 30 different workloads that each require a management group and a child management group for "dev/test/production", you're left with:

30 (no. of workloads) X 4 (no. of management groups per workload) = 120 management groups

Example of a suboptimal management group hierarchy

Diagram of an example of a sub-optimal management group hierarchy for enterprise-scale architecture when handling dev/test/production landing zones.

To summarize, there should be no difference in policies applied between "dev/test/production" environments if you develop and build them to production standard from the start. There's little value in changing the configuration of a workload as it's promoted through the different environments. Constant change results in a poor development experience for landing zone users and owners. You might also consider using "sandbox" subscriptions for true development purposes where a less restricted environment is required, such as when an application or service workload team is trying out different Azure services to see what works best for their requirements. Once the services are known, a landing zone (in the correct workload archetype aligned management group in the "landing zones" management group hierarchy) can be provisioned for the team.

A common challenge to this approach is that you might need some policies to apply differently, depending on the environment. You have a few options:

  • Use tags in your policy definitions to help filter and apply them to the correct environment.

    Important

    Tags can be changed by users with appropriate Azure RBAC permissions, so for security focused policies, we don't advise using tags in policies. Users might change the tags on a resource and potentially bypass or apply another policy definition to the resources.

  • Apply policies at a subscription level as required, ideally during the subscription creation process (as mentioned earlier).

  • For policies that are implemented to help control costs (for example, to restrict certain VM SKUs from being used), apply the policy definition at a subscription level where required or make costs the responsibility of the landing zone owners, enabling true autonomy. (See Platform automation and DevOps.)

  • Use sandbox subscriptions for development activities. Sandboxes have a less restrictive policy set.

Example of an optimal management group hierarchy aligned to enterprise-scale architecture

Screenshot that shows an example of a optimal management group hierarchy for enterprise-scale architecture when handling development, test, and production landing zones

Some management groups have been removed for illustration clarity purposes.

Note

We discussed this topic in our enterprise-scale community call in August 2021. You can find the recording on YouTube.

Why are we asked to specify Azure regions during the Azure landing zone accelerator deployment and what are they used for?

When you deploy enterprise-scale architecture by using the Azure landing zone accelerator portal-based experience, select an Azure region to deploy into. The first tab, Deployment location, determines where the deployment data is stored. For more information, see Tenant deployments with ARM templates.

Management groups, Azure Policies, and Azure RBAC are all stored at either a tenant or management group level within enterprise-scale architecture, so these resources aren't "deployed" to a particular region. The metadata regarding their deployment is stored in the region selected on the Deployment location tab.

The region selector on the Deployment location tab is also used to select which Azure region the following resources are deployed to (if enabled):

  • Log Analytics workspace (including selected solutions)
  • Automation account
  • Resource groups (for the other resources)

If you deploy a networking topology on the Network topology and connectivity tab, you'll need to select an Azure region to deploy the networking resources to. This region can be different from the region selected on the Deployment location tab. Depending on the topology you select, the networking resources that you deploy might include:

  • Azure Virtual WAN (including Virtual WAN Hub)
  • Azure Virtual Network
  • VPN gateway
  • ExpressRoute gateway
  • Azure Firewall
  • Azure DDoS Standard protection plan
  • Azure Private DNS zones for Azure Private Link
  • Resource groups (for these resources)

How do we enable more Azure regions when we use enterprise-scale architecture?

Enterprise-scale architecture itself is region-agnostic. However, you're asked to specify Azure regions to deploy enterprise-scale architecture. For more information, see Why are we asked to specify Azure regions during the Azure landing zone accelerator deployment and what are they used for.

You might want to expand into or use more Azure regions once you've completed the initial deployment of enterprise-scale architecture. For example, if you enable disaster recovery for your virtual machines by using Azure Site Recovery, you might want to replicate them to a different Azure region. To add Azure regions within enterprise-scale architecture, consider the following areas and recommendations:

Area Recommendation
Management groups No action necessary. Management groups aren't tied to a region.
Azure Policy Make changes here if you assigned policies to deny resource deployment to all regions by specifying a list of "allowed" Azure regions. These assignments must be updated to allow resource deployments to the new region you want to enable.
Role-based access control No action necessary. Azure RBAC isn't tied to a region.
Logging No action necessary. Keep sending and storing logs in the central Log Analytics Workspace in the Management subscription. See the recommendations in the enterprise-scale critical design area for Management and monitoring.
Networking If you deployed a networking topology, Virtual WAN, or traditional hub and spoke, expand the networking to the new Azure region. Create another networking hub by deploying the required networking resources into the existing Connectivity subscription in the new Azure region. From a DNS perspective, you might also want to deploy forwarders, if used, into the new Azure region. Use forwarders for spoke VNETs in the new region for resolution. Remember that Azure DNS Zones are global resources and not tied to a single Azure region, so nothing needs to be done to them.
Identity If you deployed Active Directory Domain Services or Azure Active Directory Domain Services into your Identity subscription/spoke, expand the service into the new Azure region.

Note

You might be able to use Availability Zones instead of deploying into an additional Azure region. Review and assess whether this is possible based on your requirements and whether Availability Zones are supported in your region and for the services you want to use.