cloud-foundation-fabric/modules/net-ilb

Internal Load Balancer Module

This module allows managing a GCE Internal Load Balancer and integrates the forwarding rule, regional backend, and optional health check resources. It's designed to be a simple match for the compute-vm module, which can be used to manage instance templates and instance groups.

TODO

• do not create health check resource if var.health_check is not null (workaround is to set var.health_check_config to null
• add a variable for setting address purpose to SHARED_LOADBALANCER_VIP and an output for the address once the provider support has been implemented

Issues

TODO(ludoo): check if this is still the case after splitting out MIG from compute-vm

There are some corner cases (eg when switching the instance template from internal service account to an externally managed one) where Terraform raises a cycle error on apply. In these situations, run successive applies targeting resources used in the template first then the template itself, and the cycle should be fixed.

One other issue is a Provider produced inconsistent final plan error which is sometimes raised when switching template version. This seems to be related to this open provider issue, but it's relatively harmless since the resource is updated, and subsequent applies raise no errors.

Example

This example spins up a simple HTTP server and combines four modules:

• nginx from the cloud-config-container collection, to manage instance configuration
• compute-vm to manage the instance template and unmanaged instance group
• this module to create an Internal Load Balancer in front of the managed instance group

Note that the example uses the GCE default service account. You might want to create an ad-hoc service account by combining the iam-service-accounts module, or by having the GCE VM module create one for you. In both cases, remember to set at least logging write permissions for the service account, or the container on the instances won't be able to start.

module "cos-nginx" {
  source = "./modules/cloud-config-container/nginx"
}

module "instance-group" {
  source     = "./modules/compute-vm"
  project_id = "my-project"
  region     = "europe-west1"
  zone       = "europe-west1-b"
  name       = "ilb-test"
  network_interfaces = [{
    network    = local.network_self_link,
    subnetwork = local.subnetwork_self_link,
    nat        = false,
    addresses  = null
  }]
  boot_disk = {
    image = "projects/cos-cloud/global/images/family/cos-stable"
    type  = "pd-ssd"
    size  = 10
  }
  tags                   = ["http-server", "ssh"]
  metadata = {
    user-data = module.cos-nginx.cloud_config
  }
  group = {}
}

module "ilb" {
  source        = "./modules/net-ilb"
  project_id    = "my-project"
  region        = "europe-west1"
  name          = "ilb-test"
  service_label = "ilb-test"
  network       = local.network_self_link
  subnetwork    = local.subnetwork_self_link
  ports         = [80]
  backends = [{
    failover       = false
    group          = module.instance-group.group.self_link
    balancing_mode = "CONNECTION"
  }]
  health_check_config = {
    type = "http", check = { port = 80 }, config = {}, logging = true
  }
}

Variables

name	description	type	required	default
backends	Load balancer backends, balancing mode is one of 'CONNECTION' or 'UTILIZATION'.	list(object({...}))	✓
name	Name used for all resources.	string	✓
network	Network used for resources.	string	✓
project_id	Project id where resources will be created.	string	✓
region	GCP region.	string	✓
subnetwork	Subnetwork used for the forwarding rule.	string	✓
address	Optional IP address used for the forwarding rule.	string		null
backend_config	Optional backend configuration.	object({...})		null
failover_config	Optional failover configuration.	object({...})		null
global_access	Global access, defaults to false if not set.	bool		null
health_check	Name of existing health check to use, disables auto-created health check.	string		null
health_check_config	Configuration of the auto-created helth check.	object({...})		...
labels	Labels set on resources.	map(string)		{}
log_sample_rate	Set a value between 0 and 1 to enable logging for resources, and set the sampling rate for backend logging.	number		null
ports	Comma-separated ports, leave null to use all ports.	list(string)		null
protocol	IP protocol used, defaults to TCP.	string		TCP
service_label	Optional prefix of the fully qualified forwarding rule name.	string		null

Outputs

name	description	sensitive
backend	Backend resource.
backend_id	Backend id.
backend_self_link	Backend self link.
forwarding_rule	Forwarding rule resource.
forwarding_rule_address	Forwarding rule address.
forwarding_rule_id	Forwarding rule id.
forwarding_rule_self_link	Forwarding rule self link.
health_check	Auto-created health-check resource.
health_check_self_id	Auto-created health-check self id.
health_check_self_link	Auto-created health-check self link.