Gateway Load Balancer Module for Azure

A Terraform module for deploying a Gateway Load Balancer for VM-Series firewalls.

Usage

In order to use GWLB, below minimal definition of Gateway Load Balancer can be used, for which:

• only name, VNet and subnet are defined
• default frontend IP configuration is used (Dynamic IPv4)
• zones 1, 2, 3 are configured (GWLB is zone redundant)
• default load balancing rule is used (with default load distribution)
• default health probe is used (protocol TCP on port 80)
• default 1 backend is configured (with 2 tunnel interfaces on ports 2000, 2001)

  gwlb = {
    name = "vmseries-gwlb"

    frontend_ip = {
      vnet_key   = "security"
      subnet_key = "data"
    }
  }

For more customized requirements, below extended definition of GWLB can be applied, for which:

• frontend IP has custom name and static private IP address
• there are no zones defined
• custom name for load balancing rule is defined
• custom name and port for health probe is configured
• 2 backends are defined (external and internal)

  gwlb2 = {
    name  = "vmseries-gwlb2"
    zones = []

    frontend_ip = {
      name               = "custom-name-frontend-ip"
      vnet_key           = "security"
      subnet_key         = "data"
      private_ip_address = "10.0.1.24"
    }

    lb_rule = {
      name = "custom-name-lb-rule"
    }

    health_probe = {
      name = "custom-name-health-probe"
      port = 80
    }

    backends = {
      ext = {
        name = "external"
        tunnel_interfaces = {
          external = {
            identifier = 801
            port       = 2001
            protocol   = "VXLAN"
            type       = "External"
          }
        }
      }
      int = {
        name = "internal"
        tunnel_interfaces = {
          internal = {
            identifier = 800
            port       = 2000
            protocol   = "VXLAN"
            type       = "Internal"
          }
        }
      }
    }
  }

Reference

Requirements

• terraform, version: >= 1.5, < 2.0
• azurerm, version: ~> 3.98

Providers

• azurerm, version: ~> 3.98

Resources

• lb (managed)
• lb_backend_address_pool (managed)
• lb_probe (managed)
• lb_rule (managed)

Required Inputs

Name	Type	Description
name	string	The name of the Azure Load Balancer.
resource_group_name	string	The name of the Resource Group to use.
region	string	The name of the Azure region to deploy the resources in.
frontend_ip	object	Frontend IP configuration of the Gateway Load Balancer.

Optional Inputs

Name	Type	Description
tags	map	The map of tags to assign to all created resources.
zones	list	Controls zones for Gateway Load Balancer's Fronted IP configurations.
health_probe	object	Health probe configuration for the Gateway Load Balancer backends.
backends	map	Map with backend configurations for the Gateway Load Balancer.
lb_rule	object	Load balancing rule configuration.

Outputs

Name	Description
backend_pool_ids	Backend pools' identifiers.
frontend_ip_config_id	Frontend IP configuration identifier.

Required Inputs details

name

The name of the Azure Load Balancer.

Type: string

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resource_group_name

The name of the Resource Group to use.

Type: string

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region

The name of the Azure region to deploy the resources in.

Type: string

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frontend_ip

Frontend IP configuration of the Gateway Load Balancer.

Following settings are available:

• name - (string, required) name of the frontend IP configuration. var.name by default.
• subnet_id - (string, required) id of a subnet to associate with the configuration.
• private_ip_address - (string, optional) private IP address to assign.
• private_ip_address_version - (string, optional, defaults to IPv4) the IP version for the private IP address. Can be one of "IPv4", "IPv6".

Type:

object({
    name                       = string
    subnet_id                  = string
    private_ip_address         = optional(string)
    private_ip_address_version = optional(string, "IPv4")
  })

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Optional Inputs details

tags

The map of tags to assign to all created resources.

Type: map(string)

Default value: map[]

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zones

Controls zones for Gateway Load Balancer's Fronted IP configurations.

Setting this variable to explicit null disables a zonal deployment. This can be helpful in regions where Availability Zones are not available.

Type: list(string)

Default value: [1 2 3]

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health_probe

Health probe configuration for the Gateway Load Balancer backends.

Following settings are available:

• name - (string, required) name of the health probe.
• protocol - (string, required) protocol used by the health probe, can be one of "Tcp", "Http" or "Https".
• port - (number, optional) port to run the probe against.
• probe_threshold - (number, optional) number of consecutive probes that decide on forwarding traffic to an endpoint.
• interval_in_seconds - (number, optional) interval in seconds between probes, with a minimal value of 5.
• request_path - (string, optional) used only for non Tcp probes, the URI used to check the endpoint status when protocol is set to Http(s).

Type:

object({
    name                = string
    protocol            = string
    port                = optional(number)
    probe_threshold     = optional(number)
    interval_in_seconds = optional(number)
    request_path        = optional(string, "/")
  })

Default value: map[name:health_probe port:80 protocol:Tcp]

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backends

Map with backend configurations for the Gateway Load Balancer. Azure GWLB rule can have up to two backends.

Following settings are available:

• name - (string, required) name of the backend.
• tunnel_interfaces - (map, required) map with tunnel interfaces:
  • identifier - (number, required) interface identifier.
  • port - (number, required) interface port.
  • type - (string, required) either "External" or "Internal".

Note!
If one backend is specified, it has to have both external and internal tunnel interfaces specified. For two backends, each has to have exactly one.

On GWLB inspection enabled VM-Series instance, identifier and port default to:

• 800/2000 for Internal tunnel type
• 801/2001 for External tunnel type

Variable default reflects this configuration on GWLB side. Additionally, for VM-Series tunnel interface protocol is always VXLAN.

Type:

map(object({
    name = string
    tunnel_interfaces = map(object({
      identifier = number
      port       = number
      protocol   = optional(string, "VXLAN")
      type       = string
    }))
  }))

Default value: map[backend:map[name:backend tunnel_interfaces:map[external:map[identifier:801 port:2001 protocol:VXLAN type:External] internal:map[identifier:800 port:2000 protocol:VXLAN type:Internal]]]]

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lb_rule

Load balancing rule configuration.

Available options:

• name - (string, optional) name for the rule.
• load_distribution - (string, optional, defaults to Default) specifies the load balancing distribution type to be used by the Gateway Load Balancer. Can be one of "Default", "SourceIP", "SourceIPProtocol".

Type:

object({
    name              = string
    load_distribution = optional(string, "Default")
  })

Default value: map[name:lb_rule]

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