TelemetryLink Terraform Creation State

[ozanichkovsky]

Description

As confirmed by a note within the STACKIT portal, audit logs of a hierarchy object (org/folder/project) can only be sent to one single telemetry router. This is further reflected in the portal itself, which only allows the creation of one single telemetry link per hierarchy object.
Observed Behavior:
Despite this constraint, the Terraform provider behaves inconsistently in this regard:

• In some cases, it is possible to create two telemetry links on the same hierarchy object without any immediate error being raised.
• However, when subsequently attempting to modify or delete these resources, the provider throws strange and unclear error messages, making it difficult to remediate the situation.

Steps to reproduce

resource "stackit_telemetrylink" "link" {
  resource_type       = "project"
  resource_id         = "e0335458-e68b-4c19-b844-f39cd44a2dc6"
  region              = "eu01"
  display_name        = "telemetrylink-example"
  access_token        = "eyJxxx"
  telemetry_router_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
}

resource "stackit_telemetrylink" "link2" {
  resource_type       = "project"
  resource_id         = "e0335458-e68b-4c19-b844-f39cd44a2dc6"
  region              = "eu01"
  display_name        = "telemetrylink-example"
  description         = "telemetrylink description"
  access_token        = "eyJxxx"
  telemetry_router_id = "xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx"
}

1. Run terraform ...
2. See two states are created for the same resource hierarchy.

Actual behavior

Despite this constraint, the Terraform provider behaves inconsistently in this regard:
• In some cases, it is possible to create two telemetry links on the same hierarchy object without any immediate error being raised.
• However, when subsequently attempting to modify or delete these resources, the provider throws strange and unclear error messages, making it difficult to remediate the situation.

Expected behavior

The Terraform provider should enforce the one-telemetry-link-per-hierarchy-object constraint consistently and return a clear, descriptive error message at creation time if a telemetry link already exists for the given hierarchy object — rather than allowing an invalid state to be created silently.
Impact:
This behavior can lead to an inconsistent Terraform state, making infrastructure management unreliable and causing confusion during plan/apply/destroy operations.

Environment

• OS:
• Terraform version (see terraform --version): v1.15.7
• Version of the STACKIT Terraform provider: v0.101.0

Additional information

Feel free to add any additional information here.