net-lb-app-ext and AutoNEG

[dcardellino24]

Hey there,

We are using some of the modules created here, one of them I currently struggle with is net-lb-app-ext

I created Health Checks, URLMap and my backend services like this:

backend_service_configs = {
  podinfo = {
    backends = []
    health_checks = ["podinfo"]
    project_id = "gke-0"
    cdn_policy = {
      cache_key_policy = {
        include_host         = true
        include_protocol     = true
        include_query_string = true
      }
      cache_mode                   = "USE_ORIGIN_HEADERS"
      signed_url_cache_max_age_sec = 3600
    }
    custom_request_headers = ["X-Forwarded-Proto: https", "X-Forwarded-Port: 443"]
    enable_cdn             = true
    log_sample_rate        = 1
    port_name              = "http"
    protocol                  = "HTTP"
    timeout_sec            = 86400
  }
}

health_check_configs = {
  podinfo = {
    project_id = "gke-0"
    http = {
      port = 9898
      request_path = "/healthz"
    }
    check_interval_sec  = 10
    timeout_sec         = 5
    healthy_threshold   = 3
    unhealthy_threshold = 3
  }
}


urlmap_config = {
  default_service = "podinfo"
  host_rules = [{
    hosts        = ["*"]
    path_matcher = "podinfo"
  }]
  path_matchers = {
    podinfo = {
      default_service = "podinfo"
      route_rules = [{
        match_rules = [{
          ignore_case = true
          path = {
            type  = "prefix"
            value = "/"
          }
        }]
        priority = 1
        service  = "podinfo"
      }]
    }
  }
}

If I ran a plan after applying and the Kubernetes Service is attached to the backends, terraform tries to remove the NEGs from the backend:

# module.loadbalancer.google_compute_backend_service.default["podinfo"] will be updated in-place
~ resource "google_compute_backend_service" "default" {
     id                                            = "projects/gke-0/global/backendServices/analytics-podinfo"
     name                                          = "analytics-podinfo"
     # (25 unchanged attributes hidden)
   - backend {
       - balancing_mode                      = "RATE" -> null
       - capacity_scaler                     = 1 -> null
       - group                               = "https://www.googleapis.com/compute/v1/projects/gke-0/zones/northamerica-northeast1-a/networkEndpointGroups/analytics-podinfo" -> null
       - max_connections                     = 0 -> null
       - max_connections_per_endpoint        = 0 -> null
       - max_connections_per_instance        = 0 -> null
       - max_in_flight_requests              = 0 -> null
       - max_in_flight_requests_per_endpoint = 0 -> null
       - max_in_flight_requests_per_instance = 0 -> null
       - max_rate                            = 0 -> null
       - max_rate_per_endpoint               = 1000 -> null
       - max_rate_per_instance               = 0 -> null
       - max_utilization                     = 0 -> null
         # (3 unchanged attributes hidden)
     }
   - backend {
       - balancing_mode                      = "RATE" -> null
       - capacity_scaler                     = 1 -> null
       - group                               = "https://www.googleapis.com/compute/v1/projects/gke-0/zones/northamerica-northeast1-c/networkEndpointGroups/analytics-podinfo" -> null
       - max_connections                     = 0 -> null
       - max_connections_per_endpoint        = 0 -> null
       - max_connections_per_instance        = 0 -> null
       - max_in_flight_requests              = 0 -> null
       - max_in_flight_requests_per_endpoint = 0 -> null
       - max_in_flight_requests_per_instance = 0 -> null
       - max_rate                            = 0 -> null
       - max_rate_per_endpoint               = 1000 -> null
       - max_rate_per_instance               = 0 -> null
       - max_utilization                     = 0 -> null
         # (3 unchanged attributes hidden)

Is there any way around this?

[juliocc]

I'd say this is WAI. GKE is updating the LB config and terraform is trying to make it match its definition.

You could remove the backend configs from the code and do a terraform state rm to prevent terraform from overriding the GKE changes.