Overview

Introduction

There is a lot of content in these labs, and it will make more sense if you know how the moving parts are connected.

This page will help you to understand how Azure Landing Zones (and Sovereign Landing Zones) make use of the library format and the Azure Verified Modules in the Terraform Registry, and how we use the ALZ Accelerator to speed up and standardise the deployment process. This will be a brief introduction to help level set, and you can expect to find a lot of friendly URLs to take you through to the official Microsoft documentation.

In the last section we will then run through the structure of the labs so that you understand the flow.

Azure landing zone

The Microsoft Cloud Adoption Framework gives guidance for partners and customers to adopt Azure, integrate with their existing IT infrastructure and migrate and modernize workloads. The main documentation area is https://aka.ms/caf and the overview page is recommended reading.

Diagram showing the phases of the Cloud Adoption Framework:

The third stage of the Cloud Adoption Framework (after Strategy and Plan) is Ready, and this is the focus of these labs. The Ready stage covers a number of topics, and one of those the guidance for creating a landing zone for Azure workloads to be migrated or deployed to.

Here is a generalised view of a landing zone:

The landing zone is split into a platform landing zone - which covers management group structure and associated governance policy guardrails plus shared services for connectivity, identity, management, and security - and the multiple application landing zones which are deployed under the management group structure - inheriting the policies from the management groups above - and used for the workload resources themselves.

The guidance here is generalised and many organisations have created their own definitions to meet the guidance, often using infrastructure as code. However, many pushed Microsoft to provide IP to accelerate and standardise a landing zone, and, to cut a long story short, we now have the Azure landing zone (and the Sovereign landing zone variant) as opinionated platform landing zones.

Azure Landing Zone reference architecture:

Note that this is a full implementation with resource in all of the platform landing zone subscriptions, plus a selection of application landing zone subscriptions, sandbox etc. Note that there is a smaller and more cost conscious SMB variant released.

Libraries

The Azure Landing Zones (ALZ) Library is a repo structure of governance resources defined in JSON (with partial support for YAML) used by Azure landing zones to define the management group structure and the governance defined there. The library format was defined by Microsoft’s Customer Architecture and Engineering (CAE) team as a standard.

There are numerous clients that use it, including Bicep and the Azure Portal, but the scope is reduced on these pages to the alz Terraform provider and the AVM modules. More on these soon.

The default repo is https://aka.ms/alz/library and this has a link to the core documentation. The library contains three core platform libraries:

• platform/alz - Core Azure landing zone
• platform/slz - Sovereign landing zone (dependant on platform/alz)
• platform/amba - Azure Monitor Baseline Alerts

These are all frequently updated and version numbers are used on each release.

A library may include the following core assets:

• policy definitions
• policy set definitions
• policy Assignments
• custom RBAC role definitions

These are then collated as named archetypes. The archetype_overrides are used to create variants of the core archetypes. The archetypes are then signed to the management group scopes defined in the architecture. These also define the management group hierarchy. Optionally there is a policy default values file used where the same parameter values can be reused and mapped to the parameter names used in multiple policy assignments. Finally there is a metadata file that defines the name and description and any dependencies on other libraries.

Each file in a library is defined by a schema and the alzlib Go module at the heart of all of the clients is specific about the naming convention of the files. As mentioned, the library supports full customization, allowing you to override archetypes or modify implementations. You can also have multiple library references and dependencies, opening up the ability to have:

• Custom partner libraries
• Country and industry-specific packs to address sovereignty requirements

These labs will help to understand how to use the provided libraries, customise them, or create your own custom libraries.

Terraform

The Azure landing zone and Sovereign landing zone are intended to be used by multiple clients, including Bicep. These pages focus purely on Terraform as a client, so in this section we will run through the alz provider, Azure Verified Modules, and the AVM modules in the Terraform Registry. Again, everything in this section is the product of the CAE team that created the library format.

The alz provider

The Azure landing zone library format is read on Terraform using the alz provider and then used by the Azure Verified Module. (See below.)

The alz provider is relatively simple. Its role is to download the library (or libraries) locally, into the ./alzlib folder. The folder should be excluded from your public Git provider (e.g. GitHub, Azure DevOps, etc.) using .gitignore.

It supports multiple libraries, and those libraries can also recurively pull in their own library dependencies. Most of the optional argument for the provider relate to authentication, but there are two important arguments that control behaviour.

• library_fetch_dependencies controls whether to recursively download any dependencies found in a library’s metadata file. (Default is true.)
• library_overwrite_enabled controls whether assets can be overwritten by other libraries. (Default is false.)

Azure Verified Modules

The home for Azure Verified Modules (AVM) is https://aka.ms/avm. Here you will find information on the initiative and the various resource and pattern modules that are combined to create more complex infrastructure as code deployments.

AVM has fundamentally changed the delivery of Azure landing zones, and it is more modular and better supported than ever before. There is a specific ethos behind the design and implementation of the modules and they are used for many of the platform and workload accelerators.

There is nothing stopping you from combining the AVM Terraform modules with your own Terraform config and modules, and therefore this is more appealing to partners who have defined their own infrastructure as code IP.

Terraform registry

There are five AVM modules for Azure landing zones in the Terraform registry. Each of these has an extensive documentation page, plus a selection of examples in the drop down at the top.

• Azure/avm-ptn-alz

  The core module for deploying management groups, policies definitions and assignments, and customer RBAC role definitions. This is the module that uses the alz provider and the local .alzlib folder it generates. This registry search shows all of the modules starting with Azure/avm-ptn/alz.

• Azure/avm-ptn-alz-management

  Deploys the standard Azure landing zone resource for the management subscription, such as an Azure Monitor Log Analytics Workspace for resource diagnostics, Data Collection Rules for Azure Monitor Agent, etc. This module works hand in hand with the avm-ptn-alz module as these resources are required by some of the Azure landing zone’s policies.

• Azure/avm-ptn-alz-connectivity-hub-and-spoke-vnet

  The first of two provided modules for the connectivity subscription. This one provides plenty of options for deploying standard hub and spoke resources, including gateways for ExpressRoute and VPN, Private DNS Zones and Private DNS Zone Resolver, Azure Firewall, Azure Bastion and more. Supports single and multi region deployments.

• Azure/avm-ptn-alz-connectivity-virtual-wan

  This module is for those taking the Azure Virtual WAN path for connectivity, including support for Azure Firewall, Azure Bastion, and sidecar virtual networks for NVAs and other resources that are not supported in the main hub. Supports, minimal configs through to complex multiregion deployments with many network connections.

• Azure/avm-ptn-alz-sub-vending

  Azure landing zones inherited many of the design concepts from enterprise-scale landing zones, and one of those was the use of subscriptions as a scaling element and a strong scope for RBAC role assigmments. Subscription vending is a recommended mechanism for dynamic environments.

ALZ Accelerator

The ALZ Accelerator is used by customers, partners, and Microsoft’s own Factory to accelerate deployments of Azure landing zones. Use of the ALZ accelerator is not mandatory, but there are two core benefits of using the accelerator:

1. Defines a best practice recommendation for CI/CD of your infrastructure as code configurations, including repo branch protections, approval processes and custom pipeline definitions; use of OpenID Connect and least privilege Managed Identities, and more. Supports configuration of GitHub, Azure DevOps, or local filesystem.
2. A system generated config for either Bicep or Terraform using the Azure Verified Modules. A number of default scenarios are supported via the starter modules. For Terraform this includes single or multi region deployments, hub and spoke or Azure Virtual WAN, and Azure Firewall or NVA, as well as the simple management group only configuration.

The official ALZ Accelerator documentation covers all of the various options and customisation.

This approach allows us to take advantage of the CI/CD standards and benefits, whilst forcing us to build up a management group and management config manually using the examples in the Terraform module documentation. This is for deeper enablement so that partners are in a better position to support customisation needed for different go to market scenarios and customer requirements.

What is in these labs?

The Azure landing zone and Sovereign landing zone areas contain linked lab series that are designed to help you go deeper on Azure policy at scale. Here is a quick overview of what they cover.

• Overview

  A brief overview of the various moving parts with Azure landing zones and Sovereign landing zones. Start here!

• Run the ALZ Accelerator

  This series focuses purely on the ALZ Accelerator and the intention is to create a working CI/CD pattern that is suitable for a production environment. Note that the ALZ Accelerator is also usually used to generate the starter configs, but these pages intentionally create an empty config, ready for the next stage.

• Deploy an Azure or Sovereign landing zone

  You will start with that empty config created by the ALZ Accelerator. The idea is to build up your knowledge on how the Azure Verified Modules (AVM) are used to deploy the core Azure Landing Zone management group and management configurations. Learn about the Azure Landing Zone pattern modules in the Terraform Registry, including the examples you can reference to build up your own config. Learn how to add in a custom library so that you can override the archetypes in the ALZ library.

• Understanding libraries

  OK, time to backtrack. The ALZ platform library (plus SLZ and AMBA) are core to how this all works, and you can create your own ALZ libraries as well, which can be very useful for partners. This allows you to create your own custom libraries if you want to offer a standard set of additional policy controls for customers, or policy packs for sovereign requirements in specific regions or industries. This deep dive will take you into the assets and constructs, plus some useful commands for testing that your custom policies and RBAC role definitions are valid JSON.

• Reference configs

  OK, so now you have the core understanding. But you don’t want to have to read through all of the pages if you come back at a later point, you just want to get straight to the core info and see how your files should be configured for different library scenarios. Here are a few pages for you to reference.

Next

OK, that should have given you a decent overview of what we are covering here. Enjoy!