Document the need to add pubsub roles to the read-only SA in bootstrap in specific use cases

[mlutx]

Describe the bug

When logSink is defined, running FAST CICD with Git Action failed at the plan phase, reporting error about could not check IAM policy about the Pub/Sub topics. Permission 'pubsub.topics.getIamPolicy' requires pubsub.admin role, a simple viewer role does not have access.

It also reported that cannot remove the lock on TF state file due to 'storage.objects.delete' permission missing. The predefined role 'storage.objectUser' role has that permission.

Environment

Terraform v1.8.1
on linux_amd64
+ provider registry.terraform.io/hashicorp/google v5.43.0
+ provider registry.terraform.io/hashicorp/google-beta v5.43.0
+ provider registry.terraform.io/hashicorp/local v2.5.1

Your version of Terraform is out of date! The latest version
is 1.9.5. You can update by downloading from https://www.terraform.io/downloads.html

dc0a27b8

To Reproduce

Follow the CICD steps in 0-bootstrap phase, stage bootstrap in a Github repo and set up Git Action.

Create a PR, which triggers a plan build, and build will fail with the errors.

An alternative way to check is to run the following command with an account that can impersonate into the 0r service account to validate the permission issue:

gcloud pubsub topics get-iam-policy projects/prefix-prod-audit-logs-0/topics/prefix-audit-logs --impersonate-service-account prefix-prod-bootstrap-0r@prefix-prod-iac-core-0.iam.gserviceaccount.com

Expected behavior

Git Action should complete the plan cleanly without error.

Result

Error: Error when reading or editing Resource "pubsub topic \"projects/prefix-prod-audit-logs-0/topics/prefix-workspace-audit-logs\"" with IAM Member: Role "roles/pubsub.publisher" Member "serviceAccount:[email protected]": Error retrieving IAM policy for pubsub topic "projects/prefix-prod-audit-logs-0/topics/prefix-workspace-audit-logs": googleapi: Error 403: User not authorized to perform this action.

Additional context
Add any other context about the problem here

[mlutx]

Add these two roles to the bootstrap 0r service account solves the bootstrap plan phase issue. Similar permission issues may affect resman plan phase as well, will report if found.

roles/pubsub.admin
roles/storage.objectUser

in organization-iam.tf file.

[ludoo]

Thanks for investigating the fix. Can you send a PR?

[sudhirrs]

Wouldn't giving admin rights to the 0r service accounts be a risk? I have had other similar issues with the plan related service accounts and ended up creating separate custom role along the lines of
name: iacViewer
includedPermissions:

• essentialcontacts.contacts.get
• essentialcontacts.contacts.list
• logging.settings.get
• orgpolicy.constraints.list
• orgpolicy.policies.list
• orgpolicy.policy.get
  ...
  So for any such issues - I just add the specific get/list permission.

[ludoo]

Yes, the plan is absolutely to add a custom role. Was mentioning this in a direct chat, sorry for not circling back here to say the same and good catch :)

[ludoo]

Gave this some thoughts, and I'm not convinced we should add a role for pubsub by default: FAST comes preconfigured with log sinks using log buckets as destinations, so the role is not needed by default; and granting it at the organization level might be undesired for some (or many) customers.

In general, FAST's expectation is that sinks requiring pubsub are generally used to pipe security-related records to onprem SIEMs, and those are best handled in a security-specific stage. Sinks in the bootstrap stage are mainly concerned with making some critical organization-level data easily consumable for operations, and for that use case log buckets are a good choice.

What we should do instead is making this explicit in the stage's README, so the relevant role can be added via the local tfvars file when in cases where handling pubsub sink destination in a separate stage is not desired or requires too much effort.

As for storage permissions, the read-only plan is run without a lockfile on purpose so those are not needed.