AWS Landing Zone Comparison

By Mohammad Alhussan12. October 2022

You are on your path to migrate your teams’ workloads to AWS, whether from on-premise or from other cloud providers? Then you have most probably stumbled upon the term “Landing Zones” being an important piece in the puzzle to a smoother cloud migration journey. If this term does not ring a bell, check out our blog post about landing zone lifecycle. Simply put, landing zones should set your foundation in AWS according to your organization’s security and compliance requirements.

It is not often the case that only one landing zone solution exists. This poses the challenge of choosing the right landing zone implementation for the right use case.

In this blog post we go through AWS’ ecosystem on landing zones. The goal is that after you finish reading, you will have a clearer picture on different AWS landing zone solutions to help you choose the landing zone solution that fits most to your organization.

ℹ️ Note that custom-built landing zone solutions are out of the scope of this blog post.
💡 If you are interested in Landing Zone solutions for Azure or GCP, please have a look at our comparison blog posts of these cloud platforms.

AWS Landing Zone Ecosystem

When starting your journey to search for a best fit landing zone option to pursue, you will most certainly come across different solutions. We will mainly describe a set of landing zone solutions that are provided and maintained, or recommended by AWS, namely AWS Control Tower (with plain account factory or account factory for terraform) and AWS Landing Zone Accelerator.

There are other solutions that we will not cover in the comparison, namely AWS Landing Zone and AWS Secure Environment Accelerator (SEA). The former being on long term support and not receiving more features, as well as not being recommended by AWS. The latter being targeted on governmental and public sector environments that require high-level of restrictions. We will give a brief explanation on each solution, but if you are interested in comparing these solutions as well, let us know know in the comments ⬇️ .

AWS Control Tower (CT)

We recommend that all new landing zones start with AWS Control Tower. AWS Control Tower helps you build out an initial prescriptive landing zone configuration, use out-of-the-box guardrails and blueprints, and create new accounts using AWS Control Tower account factory.
-AWS Documentation

This is the first solution you will probably come across. AWS repeatedly recommends this approach going forward. Unless you already have your landing zone setup customized with older approaches, you should definitely try it out.

AWS Control Tower’s main functionality is that it sets up a basic landing zone for you using multiple AWS services behind the scenes, such as AWS Organizations and AWS CloudFormation StackSets. It is pretty easy to set up as AWS provides a step-by-step walkthrough (i.e. a wizard). In that wizard, you will first choose the region of your control tower, and also have the option to deny services in regions you specify. Then you configure organizational units (OUs), shared accounts, CloudTrail (e.g. log retention periods) and encryption. Eventually, control tower will create the following:

  1. Two Organizational Units (OUs)
    Security: This OU contains shared accounts (log archive and audit accounts).
    Sandbox: This OU will be empty, to be filled with user provisioned accounts. Although its name indicates an environment with loose restrictions, by default it includes similar guardrails as all other OUs.
  2. Three shared accounts; management account (note that this account already exists, and is the account from which you setup CT) as well as already mentioned accounts under Security OU (log archive and audit accounts).
  3. A native cloud directory with preconfigured groups and single sign-on access.
  4. 20 preventive guardrails to enforce policies (using Service Control Policy (SCP)) and 3 detective guardrails to detect configuration violations (using AWS Config).

AWS Control Tower also offers an account factory where you can manually provision accounts or enroll existing accounts. These accounts are then governed by control tower. AWS also offers a framework around account factory to enable automation using a GitOps workflow which we explain in more details below.

AWS Control Tower Account Factory for Terraform (AFT)
AWS Control Tower Account Factory for Terraform
AFT is built on top of AWS Control Tower. It provides automation around account provisioning and further customizations using a GitOps approach.

AFT can be set up after setting up control tower, and is done mainly through two parts; manually creating the AFT management account and then applying the AFT terraform module. After applying the module, there will be 4 empty repositories (aft-account-customizations, aft-account-provisioning-customizations, aft-account-request, aft-global-customizations) in your configured VCS (e.g. CodeCommit, GitHub, etc.) that you need to populate with source repositories.

As shown in the “AFT Deployment Module” diagram above, AFT performs multiple automated steps to provision and modify accounts, as well as create custom resources. This is done by providing an interface to users (e.g. developers). For example, users can create a commit to aft-account-request repository (directly or through a pull-request based flow) with a file that calls the account request. The commit then triggers the configured workflow to provision an AWS account governed by CT.

AWS provides various resources to get more familiar with AFT. For information on broad concepts and some technical details, we recommend you check AWS AFT documentation. For a deep dive technical guidance, we recommend you go through AWS Control Tower Immersion / Activation Day – AFT workshop.

Landing Zone Accelerator on AWS

Landing Zone Accelerator on AWS is the latest approach by AWS to provide a solution for a secure Landing Zone based on best practices.

It is recommended to be used together with AWS Control Tower. But it also works in regions that don’t support Control Tower. In that case, it uses AWS Organizations directly and creates the intended OUs with according policies applied. It also works with AWS CloudGov (US), which is not supported by AWS Control Tower. So it is a solution that can be used by every AWS customer.

The Accelerator is completely executed via AWS native services. An AWS CloudFormation Stack is used to roll out a CodePipeline that creates and updates the Landing Zones according to the configuration that can be customized to your needs.

AWS Landing Zone Accelerator

The CodePipeline is the central component of it. It does the initial role out of the Landing Zone and also enables Continous Integration and Deployment. All that is needed to roll out changes to the Landing Zone is a commit to the Config Code Repository with the config changes you would like to apply.

Rolling it out will actually result in the following environment.

Resource Hierarchy AWS Landing Zone Accelerator

With this Resource Hierarchy responsibilities are clearly segregated into different OUs and accounts.

💡 If you try to roll out the Accelerator, please use the this page from the AWS documentation to get a step-by-step guide including pre-conditions. Without this page you will easily miss some important steps.

And when using the Accelerator in combination with AWS Control Tower, you have to make sure that you enter the management, audit and logging account email addresses of the accounts that were already created by Control Tower as the landing zone accelerator builds on top of it. Otherwise you will run into a code pipeline prepare stage issue.

AWS Landing Zone

AWS Landing Zone is currently in long-term support and will not receive any additional features. Customers who want to set up a new landing zone should review AWS Control Tower and Customizations for AWS Control Tower .
-AWS Documentation

This is the old approach on building an AWS landing zone which is based on AWS Organizations. One of its key components is the Account Vending Machine (AVM) which is a Service Catalog product that enables preconfigured account provisioning. It creates a multi-account structure; a security, logging, and a shared services account under a “Core OU”.

At the time of writing, searching over AWS Landing Zone in AWS documentation does not provide enough information and you will be redirected to AWS Control Tower in many occasions.

If you are already using this solution and are actually happy with it, let us know in the comments below!

AWS Secure Environment Accelerator (ASEA)

This solution has been around since 2020 and was initially built with focus on the Government of Canada. The main target of this project is environments that require high-level of security and restrictions such as governments and public sector organizations. It offers an opinionated and prescriptive architecture for your AWS multi-account setup, while also making it possible to customize as needed. It provides sample configurations that will build you an end-to-end landing zone.

There is extensive AWS secure environment accelerator documentation that will lay out details on the solution including workshops for both administrators and project teams.

If you are already using this solution and are actually happy with it, let us know in the comments below!

Comparing the Options

For this comparison, we assign 1 to 3 ⭐ for different aspects that we look at for these options. If a certain aspect is not covered at all we assign a ❌. Additionally, you can find some details about why we rated an aspect. These details also provide a deeper insight into how these aspects are covered within the options.

Feature Comparison

The feature comparison is based on the Cloud Foundation Maturity Model (CFMM). You can read details of what these blocks mean on the CFMM website. You can also follow the links in every row that redirect you directly to the details of the according CFMM block.

AWS Control Tower with Account Factory AWS Control Tower with AFT AWS Landing Zone Accelerator
Resource Hierarchy ⭐⭐ Creates 2 Organizational units (OUs), Security and Sandbox. It also creates 3 shared accounts; a standalone management account (not belonging to an OU), and log archive and security audit in the Security OU. The Sandbox OU remains empty to contain the new provisioned accounts. You can create new OUs based on your desired structure. They will be governed by CT. AWS also offers a sample hierarchy with additional OUs that you can manually include. ⭐⭐⭐ Additional to what CT provides, AFT offers a GitOps approach to provision accounts under specified OUs through an automated workflow. ⭐⭐⭐ By default it creates 2 OUs, Infrastructure and Security. You can easily define more OUs in the config. Another great feature it provides is the option to use a Quarantine OU where almost everything is forbidden. It is used for newly created accounts that are still under construction by the accelerator. That way unintended access or changes during creation can be avoided.
Resource Policies ⭐⭐⭐ AWS Control Tower sets up 20 preventive guardrails (implemented by SCPs) and 3 detective guardrails (implemented by AWS Config). Those are the “Mandatory” guardrails enabled by default that we see are reasonable, such as disallowing deletion of the log archive bucket, disallowing changes to AWS IAM roles set up by CT and CloudFormation, etc. There are also more guardrails available that are not enabled by default, which are “Elective” and “Strongly Recommended” guardrails. Newly provisioned accounts with Account Factory inherit guardrails from their parent OU. ⭐⭐⭐  Accounts provisioned through AFT also inherit all guardrails from their parent OU which is covered by CT. Additional policies can be applied through AFT customization framework. ⭐⭐⭐ Reasonable guardrails are applied to the default domains Infrastructure, Security and Quarantine. It is easy to also define additional guardrails or to define them for additional, custom OUs.
Centralized Audit Logs ⭐⭐⭐ Enables CloudTrail service to aggregate action and event logs into the shared Log Archive account from different AWS accounts and records them in CloudWatch. With CT release ≥ 3.0, an organization trail is created to gather event logs on an organization level instead of a member trail that gathers logs on a per account basis. ⭐⭐⭐ With AFT, you can also enable CloudTrail data events. Data events are events performed on or within a resource. These are disabled by default as they often incur high costs. This is done when deploying AFT by setting aft_feature_cloudtrail_data_events to true. ⭐⭐⭐ Uses the Log Archive Account to store the logs. It can be configured easily which logs shall be included.
Cloud Tenant Tagging ❌ No AWS account is tagged when setting up CT. ⭐ By default provisioned accounts are not tagged. It is possible to tag those accounts through a terraform variable account_tags. ❌ Only Tag Policies on the org level can be defined. They only ensure that if a certain tag is set, it complies with the definition in this policy. The policy will ignore those resources if no tags are set at all. During account creation , no tags can be set. So the tagging of Resources must be done outside of the accelerator.
Tenant Provisioning/Deprovisioning ❌ Initial provisioning of your multi AWS accounts. This does not qualify as tenant provisioning/deprovisioning, which is partly covered by account factory. ⭐⭐ AFT’s main functionality is automation around tenant provisioning. Deprovisioning is not supported. Removing the aft-account-request terraform for a specific account only removes it from AFT management. ⭐ Workload Accounts can be defined in the accounts-config.yaml. Only the very basic account information can be entered here. Tags, Service Accounts, etc cannot be defined for workload accounts.
Playground/Sandbox Environments ❌ Creates a Sandbox OU. However, it also has the same guardrails as the Security OU. ❌ No predefined Sandbox OU is available
Privileged Access Management (PAM) ⭐⭐⭐ Uses IAM Identity Center service to offer preconfigured groups. You can then add users to those groups based in their role in the organization. ⭐⭐⭐ By default, the user email set in the account request is assigned AdministratorAccess to the account. Additionally, groups created with CT are assigned with specific permissions. That is, AWSSecurityAuditPowerUsers group is assigned. AWSPowerUserAccess, AWSControlTowerAdmins group is assigned AWSOrganizationsFullAccess, AWSSecurityAuditors group is assigned AWSReadOnlyAccess to that account. ⭐⭐⭐ By default it defines only an Administrator group. But as you can base it on AWS Control Tower, you can make use of the advanced default roles created by AWS Control Tower.
Service Account Management
Virtual Networks ⭐⭐⭐ CT creates a default VPC with 3 subnets in the management account per availability zone. You can edit VPC configurations for new provisioned accounts with the account factory. For example, you can allow internet access for created subnets, which will lead to the creation of a NAT Gateway. When provisioning a new account, CT automatically deletes the default VPC and creates a new VPC configured by CT. ⭐⭐⭐ Similar to normal account factory, with addition to AFT customization framework that allows you to include additional terraform resources. ⭐⭐⭐ It provides a reasonable default network setup in the network-config.yaml. Additionally the default config contains a lot of additional options as commented code. You just have to active them and adapt to your needs.
On-Prem Connect ❌ CT workflow does not offer on-prem connection out of the box. It can however be implemented using Transit Gateways and Site-to-site VPN. AWS Control Tower workshop provides a detailed guide on interconnecting control tower accounts VPCs as well as connecting them to on-prem. ❌ While it is not supported out of the box by e.g. switching on a flag, AFT customization framework enables administrators to include terraform resources as they see fit. There are a bunch of “Site-to-Site VPN” terraform resources available that can be leveraged. ⭐⭐ It provides a TransitGateway in the network config to connect easily to a hub that makes the on-prem connect. As also directConnectGateways can be defined in the network config, everything that is needed to establish an on-prem connection is available.
Cloud Interconnect ❌ Similar to on-prem connect, CT does not offer cloud interconnect out of the box, but can be implemented as an “on-prem” connection. Additionally, AWS Control Tower workshop offers guidance on interconnecting AWS accounts VPCs. ❌ Same as for CT itself applies. ⭐⭐ In the network config directConnectGateways can be defined to connect to networks at other cloud providers.
Managed Key Vault
Automation in CI/CD ❌ Runs automation under the hood, not configurable by the user. ⭐⭐⭐ Automation is the core of AFT. It sets up a pipeline that is triggered by a code change in a version control system (VCS). It uses AWS CodeCommit natively, but also supports other alternatives such as GitHub and BitBucket. ⭐⭐ The whole Accelerator framework is based on AWS CodeBuild and CodePipelines. Any updates to the config is rolled out via that pipeline. The only downside is, that you can only use the AWS Services for it. Integrating it into any other CI/CD tool is not possible.

Non-Functional Comparison

AWS Control Tower with Account Factory AWS Control Tower with AFT AWS Landing Zone Accelerator
Extensibility/Modularity/Scalability ⭐⭐ CT only provides the baseline setup. It can be extended with “Customization for Control Tower – CfCT”. You can also create your own OU structure to which CT will also apply guardrails. ⭐⭐⭐  In addition to what can be extended and customized in CT, AFT provides a customization framework that allows users to include AWS resources with terraform. ⭐⭐ You can customize the config rather easily to your needs. But it seems like it is not possible to add completely new modules for other services easily to the Accelerator. As they have a DSL to define all the resources via their config it feels like you are pretty locked to the config options that are provided by the accelerator. But the config actually covers quite a lot of services (35+ services are mentioned in the AWS docs) and seems to be sufficient for many use-cases. But if you want to integrate an AWS service into your Landing Zone that is not yet supported by the accelerator, it looks like you have to create a Pull Request to the accelerator to get it in.
Terraform ⭐⭐ As its name suggests, it offers a workflow based on terraform. It requires a bit of ClickOps initially to create the AFT management account. ❌ It is completely based on AWS CloudFormation.
Learning Curve ⭐⭐ ⭐ It is easy to start with CT and set it up. Having an advanced AWS knowledge is not required. ⭐⭐ There are many AWS services involved in the workflow, making it a bit harder to grasp. Also, AWS account provisioning is not directly performed via terraform but an account request is created which triggers an account provisioning process. ⭐⭐ Except for some current issues, that should be related to the accelerator being quite new on the market, rolling it out is rather easy. You only have to deploy a StackSet and the rest of the bootstrapping is done automatically for you. As a next step you have to set the configuration you like to have in 6 yaml files, that are rather easy to understand. You also get a good reference implementation based on best practices where you can copy and adapt your own configuration.
Community ⭐ Scattered community across multiple platforms. There doesn’t seem to be a specific place to ask questions but you can find some answers on different platforms such as stackoverflow. ⭐⭐ In addition to different community platforms, you can open a GitHub issue in AFT repo in case you encounter problems. AFT maintainers seem to be responsive to issues, but they still don’t accept contributions at the time of writing. ⭐ As it is a rather new solution you cannot find a lot around this yet. The GitHub Repo only has 75 stars and 12 contributors yet. Only a few issues exist yet in the GitHub repo and the responsiveness of the developers is rather low at the moment. At least 2 tickets we created or commented in did not get any response from official contributors within more than a week. Eventhough community around it is still rather low, an advantage is that AWS Support fully covers support for it.
Costs ⭐⭐⭐ There are costs associated with services that CT uses such as CloudTrail and S3 buckets. The resources it creates can incur costs depending on the usage, for example the more accounts created, the more logs are ingested into the log archive account. AWS has a pricing page with details on different scenarios and how much cost is associated. Another example is, in account factory settings, you can allow internet access for created subnets in the new account, which will lead to the creation of a NAT Gateway and drive some cost. ⭐⭐ There are no additional costs for AFT but also for resources it creates. Transparency in AFT is limited and you need to figure out which options to enable/disable to control which resources are created. For example, AFT will by default create AWS PrivateLinks. In order to disable that, you need to set aft_vpc_endpoints=false when deploying the AFT terraform module. ⭐ AWS is very transparent around costs that are associated with running the best-practice landing zone. At the time of writing this article it is ±360€ per month. If you are not using all resources that are configured in the default landing zone you can save a bit of money. Main cost drivers are the KMS and the networking.
Time To Success ⭐⭐⭐ Setting up AWS Control Tower for the first time takes 1-2 hours, which includes going through “set up your landing zone” that takes roughly 15-30 minutes. This assumes that you do not have an existing setup that you need to decommission; as that will increase the time to success. ⭐⭐ Setting up AFT technically takes around ~1 hour, which includes creating the AFT management account and deploying the AFT terraform module. Post-steps like populating your repositories for automation would rather be quick. All in all, assuming the process goes smoothly, setting up CT with AFT would take ~4 hours. ⭐⭐ The concept of AWS accelerator is quite promising to set up a secure Landing Zone rather quickly due to the best practice defaults and the easy to understand configuration. But currently there is the downside that if something goes wrong while rolling out the pipeline you might receive really bad error messages that don’t help you resolving the issue. This can delay the time to success significantly. But these issues could vanish over time when the accelerator becomes more mature.

Find your way to building AWS Landing Zones

Building your landing zone in AWS eventually implies it will be built on top of either AWS Organizations directly or AWS Control Tower to enable your multi-account setup. Using either of these would also impact your decision on which landing zone solution to pursue. AWS Organizations is merely a tool that enables a multi-account setup but does not actually build a landing zone, while AWS Control Tower provides an abstraction to multiple AWS services including AWS Organizations and builds a basic landing zone that you can extend atop. The below simplified flow chart conveys the relation between the different solutions.

AWS Landing-Zone Solution Comparison

Unless you are using a region that is not supported by AWS Control Tower or you need absolute control over all the components of your landing zone, you should always go with AWS Control Tower. Most solutions nowadays support it, and it is highly recommended by AWS. But besides the guardrails it provides, there isn’t much that it adds in the meantime and it can be considered a very basic landing zone when used solo. Therefore, if you’re only interested in a basic landing zone setup that only provides you with a multi-account framework with a set of preventive and detective guardrails, then you should definitely consider AWS Control Tower.

From there you can choose to stay with only Account Factory in which you will pretty much only benefit from CT’s guardrails when provisioning accounts, or go for Account Factory for Terraform which additionally provides a GitOps based framework to automatically provision accounts with customization capabilities.

If you’re interested in an end-to-end landing zone solution, then consider AWS Landing Zone Accelerator. It is a solution that promises to build full-fledged AWS landing zones with automation capabilities. It supports both AWS Control Tower and AWS Organizations. This solution was first released on 23 May 2022 which is fairly new. We identified that the product itself and its documentation is not yet battle proven and you can run in some unexpected issues when trying to roll it out. As of this writing, we stumbled across a blocker that prevented us from actually deploying it and therefore we cannot provide a full recommendation yet. We like the simplicity and customizability of the config files that are steering the AWS Accelerator and the understandable pipeline that deploys it. But we are wondering whether more extensive customization that goes beyond the services and features supported by the configuration files of AWS Accelerator are feasible.

The different solutions presented in this blog post are actually not really alternatives that compete against each other. Instead they combine and extend each other very well. For a full-fledged Landing Zone we therefore recommend the combination of AWS Control Tower with AFT for automated account provisioning and Landing Zone Accelerator on AWS to add further highly recommended features to your Landing Zone.

Best-Practice AWS Landing Zone Solution Diagram

If the concerns we mentioned regarding the production-readiness of AWS Landing Zone Accelerator, or if you need to have full control over your landing zones, then go for a custom-built landing zone, either via an AWS partner or with your AWS team.

Did this blog post help you decide which Landing Zone Solution you will apply to AWS? Did you already gather your own insights to building an AWS Landing Zone and want to back up, add or discuss insights from this blog post, please do so and leave a comment! We look forward to hearing about your experience.