cloud-foundation-fabric/fast/stages/1-resman/README.md

Resource hierarchy

This stage performs two important tasks:

• create the top-level hierarchy of folders, and the associated resources used later on to automate each part of the hierarchy (eg. Networking)
• set organization policies on the organization, and any exception required on specific folders

The code is intentionally simple, as it's intended to provide a generic initial setup (Networking, Security, etc.), and then allow easy customizations to complete the implementation of the intended hierarchy design.

The following diagram is a high level reference of the resources created and managed here:

Design overview and choices

Despite its simplicity, this stage implements the basics of a design that we've seen working well for a variety of customers, where the hierarchy is laid out following two conceptually different approaches:

• core or shared resources are grouped in hierarchy branches that map to their type or purpose (e.g. Networking)
• team or application resources are grouped in lower level hierarchy branches that map to management or operational considerations (e.g. which team manages a set of applications, or owns a subset of company data, etc.)

This split approach usually represents well functional and operational patterns, where core resources are centrally managed by individual teams (e.g. networking, security, fleets of similar VMS, etc.), while teams need more granularity to access managed services used by the applications they maintain.

The approach also adapts to different high level requirements:

• it can be used either for single organizations containing multiple environments, or with multiple organizations dedicated to specific environments (e.g. prod/nonprod), as the environment split is implemented at the project or lower folder level
• it adapts to complex scenarios, with different countries or corporate entities using the same GCP organization, as core services are typically shared, and/or an extra layer on top can be used as a drop-in to implement the country/entity separation

Additionally, a few critical benefits are directly provided by this design:

• core services are clearly separated, with very few touchpoints where IAM and security policies need to be applied (typically their top-level folder)
• adding a new set of core services (e.g. shared GKE clusters) is a trivial operation that does not break the existing design
• grouping application resources and services using teams or business logic is a flexible approach, which maps well to typical operational or budget requirements
• automation stages (e.g. Networking) can be segregated in a simple and effective way, by creating the required service accounts and buckets for each stage here, and applying a handful of IAM roles to the relevant folder

For a discussion on naming, please refer to the Bootstrap stage documentation, as the same approach is shared by all stages.

Multitenancy

Fully multitenant hierarchies inside the same organization are implemented via separate additional stages that need to be run once for each tenant, and require this stage as a prerequisite.

Workload Identity Federation and CI/CD

This stage also implements optional support for CI/CD, much in the same way as the bootstrap stage. The only difference is on Workload Identity Federation, which is only configured in bootstrap and made available here via stage interface variables (the automatically generated .tfvars files).

For details on how to configure CI/CD please refer to the relevant section in the bootstrap stage documentation.

How to run this stage

This stage is meant to be executed after the bootstrap stage has run, as it leverages the automation service account and bucket created there. The relevant user groups must also exist, but that's one of the requirements for the previous stage too, so if you ran that successfully, you're good to go.

It's of course possible to run this stage in isolation, but that's outside the scope of this document, and you would need to refer to the code for the bootstrap stage for the actual roles needed.

Before running this stage, you need to make sure you have the correct credentials and permissions, and localize variables by assigning values that match your configuration.

Providers configuration

The default way of making sure you have the right permissions, is to use the identity of the service account pre-created for this stage during bootstrap, and that you are a member of the group that can impersonate it via provider-level configuration (gcp-devops or organization-admins).

To simplify setup, the previous stage pre-configures a valid providers file in its output, and optionally writes it to a local file if the outputs_location variable is set to a valid path.

If you have set a valid value for outputs_location in the bootstrap stage (see the bootstrap stage README for more details), simply link the relevant providers.tf file from this stage's folder in the path you specified:

# `outputs_location` is set to `~/fast-config`
ln -s ~/fast-config/providers/01-resman-providers.tf .

If you have not configured outputs_location in bootstrap, you can derive the providers file from that stage's outputs:

cd ../0-bootstrap
terraform output -json providers | jq -r '.["01-resman"]' \
  > ../1-resman/providers.tf

If you want to continue to rely on outputs_location logic, create a terraform.tfvars file and configure it as described here.

Variable configuration

There are two broad sets of variables you will need to fill in:

• variables shared by other stages (org id, billing account id, etc.), or derived from a resource managed by a different stage (folder id, automation project id, etc.)
• variables specific to resources managed by this stage

To avoid the tedious job of filling in the first group of variable with values derived from other stages' outputs, the same mechanism used above for the provider configuration can be used to leverage pre-configured .tfvars files.

If you configured a valid path for outputs_location in the bootstrap stage, simply link the relevant *.auto.tfvars.json files from the outputs folder. For this stage, you need the globals.auto.tfvars.json file containing global values compiled manually for the bootstrap stage, and 0-bootstrap.auto.tfvars.json containing values derived from resources managed by the bootstrap stage:

# `outputs_location` is set to `~/fast-config`
ln -s ~/fast-config/tfvars/globals.auto.tfvars.json .
ln -s ~/fast-config/tfvars/0-bootstrap.auto.tfvars.json .

A second set of variables is specific to this stage, they are all optional so if you need to customize them, create an extra terraform.tfvars file.

Refer to the Variables table at the bottom of this document, for a full list of variables, their origin (e.g. a stage or specific to this one), and descriptions explaining their meaning. The sections below also describe some of the possible customizations. For billing configurations, refer to the Bootstrap documentation on billing as the billing_account variable is identical across all stages.

Once done, you can run this stage:

terraform init
terraform apply

Customizations

Team folders

This stage provides a single built-in customization that offers a minimal (but usable) implementation of the "application" or "business" grouping for resources discussed above. The team_folders variable allows you to specify a map of team name and groups, that will result in folders, automation service accounts, and IAM policies applied.

Consider the following example in a tfvars file:

team_folders = {
  team-a = {
    descriptive_name = "Team A"
    group_iam = {
      "team-a@gcp-pso-italy.net" = [
        "roles/viewer"
      ]
    }
    impersonation_groups = ["team-a-admins@gcp-pso-italy.net"]
  }
}

This will result in

• a "Team A" folder under the "Teams" folder
• one GCS bucket in the automation project
• one service account in the automation project with the correct IAM policies on the folder and bucket
• a IAM policy on the folder that assigns roles/viewer to the team-a group
• a IAM policy on the service account that allows team-a to impersonate it

This allows to centralize the minimum set of resources to delegate control of each team's folder to a pipeline, and/or to the team group. This can be used as a starting point for scenarios that implement more complex requirements (e.g. environment folders per team, etc.).

Organization policies

Organization policies are laid out in an explicit manner in the organization.tf file, so it's fairly easy to add or remove specific policies.

For policies where additional data is needed, a root-level organization_policy_configs variable allows passing in specific data. Its built-in use to add additional organizations to the Domain Restricted Sharing policy, can be taken as an example on how to leverage it for additional customizations.

IAM

IAM roles can be easily edited in the relevant branch-xxx.tf file, following the best practice outlined in the bootstrap stage documentation of separating user-level and service-account level IAM policies in modules' iam_groups, iam, and iam_additive variables.

A full reference of IAM roles managed by this stage is available here.

Additional folders

Due to its simplicity, this stage lends itself easily to customizations: adding a new top-level branch (e.g. for shared GKE clusters) is as easy as cloning one of the branch-xxx.tf files, and changing names.

Files

name	description	modules	resources
billing.tf	Billing resources for external billing use cases.		google_billing_account_iam_member
branch-data-platform.tf	Data Platform stages resources.	folder · gcs · iam-service-account	google_organization_iam_member
branch-gke.tf	GKE multitenant stage resources.	folder · gcs · iam-service-account
branch-networking.tf	Networking stage resources.	folder · gcs · iam-service-account
branch-project-factory.tf	Project factory stage resources.	gcs · iam-service-account	google_organization_iam_member
branch-sandbox.tf	Sandbox stage resources.	folder · gcs · iam-service-account
branch-security.tf	Security stage resources.	folder · gcs · iam-service-account
branch-teams.tf	Team stage resources.	folder · gcs · iam-service-account
cicd-data-platform.tf	CI/CD resources for the data platform branch.	iam-service-account · source-repository
cicd-gke.tf	CI/CD resources for the data platform branch.	iam-service-account · source-repository
cicd-networking.tf	CI/CD resources for the networking branch.	iam-service-account · source-repository
cicd-project-factory.tf	CI/CD resources for the teams branch.	iam-service-account · source-repository
cicd-security.tf	CI/CD resources for the security branch.	iam-service-account · source-repository
main.tf	Module-level locals and resources.
organization.tf	Organization policies.	organization
outputs-files.tf	Output files persistence to local filesystem.		local_file
outputs-gcs.tf	Output files persistence to automation GCS bucket.		google_storage_bucket_object
outputs.tf	Module outputs.
variables.tf	Module variables.

Variables

name	description	type	required	default	producer
automation	Automation resources created by the bootstrap stage.	object({…})	✓		0-bootstrap
billing_account	Billing account id. If billing account is not part of the same org set is_org_level to false.	object({…})	✓		0-bootstrap
organization	Organization details.	object({…})	✓		0-bootstrap
prefix	Prefix used for resources that need unique names. Use 9 characters or less.	string	✓		0-bootstrap
cicd_repositories	CI/CD repository configuration. Identity providers reference keys in the automation.federated_identity_providers variable. Set to null to disable, or set individual repositories to null if not needed.	object({…})		null
custom_roles	Custom roles defined at the org level, in key => id format.	object({…})		null	0-bootstrap
data_dir	Relative path for the folder storing configuration data.	string		"data"
fast_features	Selective control for top-level FAST features.	object({…})		{}	0-0-bootstrap
groups	Group names to grant organization-level permissions.	object({…})		{}	0-bootstrap
locations	Optional locations for GCS, BigQuery, and logging buckets created here.	object({…})		{…}	0-bootstrap
organization_policy_configs	Organization policies customization.	object({…})		null
outputs_location	Enable writing provider, tfvars and CI/CD workflow files to local filesystem. Leave null to disable.	string		null
tag_names	Customized names for resource management tags.	object({…})		{…}
team_folders	Team folders to be created. Format is described in a code comment.	map(object({…}))		null

Outputs

name	description	sensitive	consumers
cicd_repositories	WIF configuration for CI/CD repositories.
dataplatform	Data for the Data Platform stage.
gke_multitenant	Data for the GKE multitenant stage.		03-gke-multitenant
networking	Data for the networking stage.
project_factories	Data for the project factories stage.
providers	Terraform provider files for this stage and dependent stages.	✓	02-networking · 02-security · 03-dataplatform · xx-sandbox · xx-teams
sandbox	Data for the sandbox stage.		xx-sandbox
security	Data for the networking stage.		02-security
teams	Data for the teams stage.
tfvars	Terraform variable files for the following stages.	✓