Add multiple GCP HA instance to Unmanaged Instance Group by Terraform

[ss39881]

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Description

I need to add multiple cross zonal GCP instances to UIG. But, below code is attaching only few instances to UIG.

It is working as expected (creating UIG and attaching instances to terraform created UIG) if var.num_instances count is greater than or equal to length(data.google_compute_zones.available.names).

But , It does not attach instance in case length(data.google_compute_zones.available.names) is less than var.num_instances.

main.tf

data "google_compute_zones" "available" {
  project = var.project
  region  = var.region
}

module "google_uig" {
  source = "C:/Users/xxxx/OneDrive/Desktop/New folder/terraform-google-core/modules/compute_engine_uig"
  depends_on = [
    module.google_vm
  ]
  project = var.project
  # count   = var.num_instances
  count   = length(data.google_compute_zones.available.names) < var.num_instances ? length(data.google_compute_zones.available.names) : var.num_instances
  zone    = var.zone == null ? data.google_compute_zones.available.names[count.index % length(data.google_compute_zones.available.names)] : var.zone
  name         = "use1${[for zone in (data.google_compute_zones.available.names): substr(zone,-1,-1)][count.index]}-oss94-mta99-app-ig01"
  instances = element((module.google_vm[*].google_instance_id), count.index)
}

terraform.tfvars

project            = "gcp-test01"
region             = "us-central1"
num_instances      = "6"
image_project      = "gcp-kcfn01"
image_name         = "centos7-kent-v20220105"
instance_name      = "kcfn01-cfn01-apoc01-app"
tags               = ["oss01-mta-app", "usc1-sss-oss-snet01-local"]
machine_type       = "n1-standard-4"
disk_size          = "50"
disk_type          = "pd-standard"
boot_disk_size     = "50"
boot_disk_type     = "pd-standard"
network            = "cfn01-sss-net"
subnetwork         = "cfn01-usc1-sss-oss-snet01"
subnetwork_project = "gcp-kcfn01"

Potential Terraform Configuration

# Propose what you think the configuration to take advantage of this feature should look like.
# We may not use it verbatim, but it's helpful in understanding your intent.

[ss39881]

@c2thorn Did you get a chance to look into it ?

[c2thorn]

Hi @ss39881, this repository is not meant for debugging modules, but individual Google provider resources. From the information provided, I cannot tell if there is an issue with a specific resource, or some misconfiguration in the module you are using. If there is an issue with a specific resource, please help us replicate the issue by reducing your configuration down to a single file with the minimum resources to replicate, provide a debug log, and open the issue as a bug.

[github-actions]

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