This add-on allows creating an arbitrary number of Compute instances and service accounts, and is designed to simplify testing of the FAST networking stage.

Design overview and choices
How to run this stage
Files
Variables
Outputs

Design overview and choices

The add-on is very simple, as it just deals with creating service accounts and instances using pre-existing projects, networks and subnets.

To allow creation of portable configurations, it extensively leverages FAST output variables so that project ids, network ids, regions, and subnet ids can refer to the relevant FAST aliases.

A simple factory is also provided, so that YAML configurations can be used instead of Terraform tfvars.

How to run this stage

Once the main networking stage has been configured and applied, the following configuration is added the the resource management fast_addon variable to create the add-on provider files, and its optional CI/CD resources if those are also required. The add-on name (networking-test) is customizable, in case the add-on needs to be run multiple times to create gateways in different projects.

fast_addon = {
  networking-test = {
    parent_stage = "2-networking"
  }
}

Provider and Terraform variables

As all other FAST stages, the mechanism used to pass variable values and pre-built provider files from one stage to the next is also leveraged here.

The commands to link or copy the provider and terraform variable files can be easily derived from the fast-links.sh script in the FAST stages folder, passing it a single argument with the local output files folder (if configured) or the GCS output bucket in the automation project (derived from stage 0 outputs). The following example uses local files but GCS behaves identically.

# File linking commands for Test resources networking add-on stage

# provider file
ln -s ~/fast-config/providers/2-networking-test-providers.tf ./

# input files from other stages
ln -s ~/fast-config/tfvars/2-networking.auto.tfvars.json ./

# conventional place for stage tfvars (manually created)
ln -s ~/fast-config/2-networking-test.auto.tfvars ./

If a factory is used and neither the default factory paths nor the resource name prefix in the name variable need to be changed, the last file is unnecessary as there's no additional configuration for this add-on.

Impersonating the automation service account

The preconfigured provider file uses impersonation to run with this stage's automation service account's credentials. The gcp-devops and organization-admins groups have the necessary IAM bindings in place to do that, so make sure the current user is a member of one of those groups.

Variable configuration

Variables in this stage -- like most other FAST stages -- are broadly divided into three separate sets:

variables which refer to global values for the whole organization (org id, billing account id, prefix, etc.), which are pre-populated via the 0-globals.auto.tfvars.json file linked or copied above
variables which refer to resources managed by previous stages, which are prepopulated here via the 0-org-setup.auto.tfvars.json, 2-networking.auto.tfvars.json files linked or copied above
and finally variables that optionally control this stage's behaviour and customizations, and can to be set in a custom terraform.tfvars file

The first two sets are defined in the variables-fast.tf file, the latter set in the variables.tf file. The full list of variables can be found in the Variables table at the bottom of this document.

Once output files are in place, define your addon configuration in a tfvars file if needed (see section above).

Running the stage

Once provider and variable values are in place and the correct user is configured, the stage can be run:

terraform init
terraform apply

Files

name	description	modules
context.tf	FAST context locals
factory.tf	Factory locals.
main.tf	Module-level locals and resources.	`compute-vm` · `iam-service-account`
outputs.tf	Module outputs.
variables-fast.tf	FAST stage interface.
variables.tf	Module variables.

Variables

name	description	type	default	producer
factories_config	Configuration for the resource factories.	`object({…})`	`{}`
host_project_ids	Networking stage host project id aliases.	`map(string)`	`{}`	`2-networking`
name	Prefix used for all resource names.	`string`	`"test"`
regions	Region aliases.	`map(string)`	`{}`	`2-networking`
subnet_self_links	Subnet self links.	`map(map(string))`	`{}`	`2-networking`
test_instances	Test instances to be created.	`map(object({…}))`	`{}`
test_service_accounts	Service accounts used by instances.	`map(object({…}))`	`{}`
vpc_self_links	VPC network self links.	`map(string)`	`{}`	`2-networking`

Outputs

name	description	sensitive	consumers
instance_addresses	Instance names and addresses.
instance_ssh	Instance SSH commands.
service_account_emails	Service account emails.