vpc-sc

VPC Service Controls

This module offers a unified interface to manage VPC Service Controls Access Policy, Access Levels, and Service Perimeters.

Given the complexity of the underlying resources, the module intentionally mimics their interfaces to make it easier to map their documentation onto its variables, and reduce the internal complexity. The tradeoff is some verbosity, and a very complex type for the service_perimeters_regular variable (while optional type attributes are still an experiment).

If you are using Application Default Credentials with Terraform and run into permissions issues, make sure to check out the recommended provider configuration in the VPC SC resources documentation.

Examples

Access policy

By default, the module is configured to use an existing policy, passed in by name in the access_policy variable:

module "test" {
  source        = "./fabric/modules/vpc-sc"
  access_policy = "12345678"
}
# tftest modules=0 resources=0

If you need the module to create the policy for you, use the access_policy_create variable, and set access_policy to null:

module "test" {
  source        = "./fabric/modules/vpc-sc"
  access_policy = null
  access_policy_create = {
    parent = "organizations/123456"
    title  = "vpcsc-policy"
  }
}
# tftest modules=1 resources=1

Access levels

As highlighted above, the access_levels type replicates the underlying resource structure.

module "test" {
  source        = "./fabric/modules/vpc-sc"
  access_policy = "12345678"
  access_levels = {
    a1 = {
      combining_function = null
      conditions = [{
        members = ["user:[email protected]"], ip_subnetworks = null,
        negate = null, regions = null,  required_access_levels = null
      }]
    }
    a2 = {
      combining_function = "OR"
      conditions = [{
        regions       = ["IT", "FR"], ip_subnetworks = null,
        members = null, negate = null, required_access_levels = null
      },{
        ip_subnetworks = ["101.101.101.0/24"], members = null,
        negate = null, regions = null, required_access_levels = null
      }]
    }
  }
}
# tftest modules=1 resources=2

Service perimeters

Bridge and regular service perimeters use two separate variables, as bridge perimeters only accept a limited number of arguments, and can leverage a much simpler interface.

The regular perimeters variable exposes all the complexity of the underlying resource, use its documentation as a reference about the possible values and configurations.

If you need to refer to access levels created by the same module in regular service perimeters, you can either use the module's outputs in the provided variables, or the key used to identify the relevant access level. The example below shows how to do this in practice.

/* Resources for both perimeters have a lifecycle block that ignores changes to spec and status resources (projects), to allow using the additive resource google_access_context_manager_service_perimeter_resource at project creation. If this is not needed, the lifecycle blocks can be safely commented in the code. */

Bridge type

module "test" {
  source        = "./fabric/modules/vpc-sc"
  access_policy = "12345678"
  service_perimeters_bridge = {
    b1 = {
      status_resources          = ["projects/111110", "projects/111111"]
      spec_resources            = null
      use_explicit_dry_run_spec = false
    }
    b2 = {
      status_resources          = null
      spec_resources            = ["projects/222220", "projects/222221"]
      use_explicit_dry_run_spec = true
    }
  }
}
# tftest modules=1 resources=2

Regular type

module "test" {
  source        = "./fabric/modules/vpc-sc"
  access_policy = "12345678"
  access_levels = {
    a1 = {
      combining_function = null
      conditions = [{
        members       = ["user:[email protected]"], ip_subnetworks = null,
        negate = null, regions = null, required_access_levels = null
      }]
    }
    a2 = {
      combining_function = null
      conditions = [{
        members       = ["user:[email protected]"], ip_subnetworks = null,
        negate = null, regions       = null, required_access_levels = null
      }]
    }
  }
  service_perimeters_regular = {
    r1 = {
      spec = null
      status = {
        access_levels       = [module.test.access_level_names["a1"], "a2"]
        resources           = ["projects/11111", "projects/111111"]
        restricted_services = ["storage.googleapis.com"]
        # example: allow writing to external GCS bucket
        egress_policies     = [
          {
            egress_from = {
              identity_type = null
              identities = [
                "serviceAccount:[email protected]"
              ]
            }
            egress_to = {
              operations = [{
                method_selectors = ["*"], service_name = "storage.googleapis.com"
              }]
              resources = ["projects/123456789"]
            }
          }
        ]
        # example: allow management from external automation SA
        ingress_policies    = [
          {
            ingress_from = {
              identities = [
                "serviceAccount:[email protected]",
              ],
              source_access_levels = ["*"], identity_type = null, source_resources = null
            }
            ingress_to = {
              operations = [{ method_selectors = [], service_name = "*" }]
              resources  = ["*"]
            }
          }
        ]
        vpc_accessible_services = {
          allowed_services   = ["storage.googleapis.com"]
          enable_restriction = true
        }
      }
      use_explicit_dry_run_spec = false
    }
  }
}
# tftest modules=1 resources=3

Notes

• To remove an access level, first remove the binding between perimeter and the access level in status and/or spec without removing the access level itself. Once you have run terraform apply, you'll then be able to remove the access level and run terraform apply again.

TODO

• implement support for the google_access_context_manager_gcp_user_access_binding resource

Variables

name	description	type	required	default
access_policy	Access Policy name, leave null to use auto-created one.	string	✓
access_levels	Map of access levels in name => [conditions] format.	map(object({…}))		{}
access_policy_create	Access Policy configuration, fill in to create. Parent is in 'organizations/123456' format.	object({…})		null
service_perimeters_bridge	Bridge service perimeters.	map(object({…}))		{}
service_perimeters_regular	Regular service perimeters.	map(object({…}))		{}

Outputs

name	description	sensitive
access_level_names	Access level resources.
access_levels	Access level resources.
access_policy	Access policy resource, if autocreated.
access_policy_name	Access policy name.
service_perimeters_bridge	Bridge service perimeter resources.
service_perimeters_regular	Regular service perimeter resources.