NAT Gateway module

Purpose

Terraform module used to deploy Azure NAT Gateway. For limitations and zone-resiliency considerations please refer to Microsoft documentation.

This module can be used to either create a new NAT Gateway or to connect an existing one with subnets deployed using (for example) the VNET module.

NAT Gateway is not zone-redundant. It is a zonal resource. It means that it's always deployed in a zone. It's up to the user to decide if a zone will be specified during resource deployment or if Azure will take that decision for the user. Keep in mind that regardless of the fact that NAT Gateway is placed in a specific zone it can serve traffic for resources in all zones. But if that zone becomes unavailable, resources in other zones will lose internet connectivity.

For design considerations, limitation and examples of zone-resiliency architecture please refer to Microsoft documentation.

Usage

To deploy this resource in it's minimum configuration following code snippet can be used (assuming that the VNET module is used to deploy VNET and Subnets):

module "natgw" {
  source = "PaloAltoNetworks/swfw-modules/azurerm//modules/natgw"

  name                = "NATGW_name"
  resource_group_name = "resource_group_name"
  location            = "region_name"
  subnet_ids          = { "subnet_name" = "/subscription/xxxx/......." }
  idle_timeout        = 120
}

This will create a NAT Gateway in with a single Public IP in a zone chosen by Azure.

Reference

Requirements

terraform, version: >= 1.5, < 2.0
azurerm, version: ~> 4.0

Providers

azurerm, version: ~> 4.0

Resources

nat_gateway (managed)
nat_gateway_public_ip_association (managed)
nat_gateway_public_ip_prefix_association (managed)
public_ip (managed)
public_ip_prefix (managed)
subnet_nat_gateway_association (managed)
nat_gateway (data)
public_ip (data)
public_ip_prefix (data)

Required Inputs

Name	Type	Description
`name`	`string`	Name of a NAT Gateway.
`resource_group_name`	`string`	Name of a Resource Group hosting the NAT Gateway (either the existing one or the one that will be created).
`region`	`string`	Azure region.
`subnet_ids`	`map`	A map of subnet IDs what will be bound with this NAT Gateway.

Optional Inputs

Name	Type	Description
`tags`	`map`	A map of tags that will be assigned to resources created by this module.
`create_natgw`	`bool`	Triggers creation of a NAT Gateway when set to `true`.
`zone`	`string`	Controls whether the NAT Gateway will be bound to a specific zone or not.
`idle_timeout`	`number`	Connection IDLE timeout in minutes (up to 120, defaults to Azure defaults).
`public_ip`	`object`	A map defining a Public IP resource.
`public_ip_prefix`	`object`	A map defining a Public IP Prefix resource.

Outputs

Name	Description
`natgw_pip`	Public IP associated with the NAT Gateway.
`natgw_pip_prefix`	Public IP Prefix associated with the NAT Gateway.

Required Inputs details

name

Name of a NAT Gateway.

Type: string

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resource_group_name

Name of a Resource Group hosting the NAT Gateway (either the existing one or the one that will be created).

Type: string

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region

Azure region. Only for newly created resources.

Type: string

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subnet_ids

A map of subnet IDs what will be bound with this NAT Gateway.

Value is the subnet ID, key value does not matter but should be unique, typically it can be a subnet name.

Type: map(string)

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Optional Inputs details

create_natgw

Triggers creation of a NAT Gateway when set to true.

Set it to false to source an existing resource. In this 'mode' the module will only bind an existing NAT Gateway to specified subnets.

Type: bool

Default value: true

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zone

Controls whether the NAT Gateway will be bound to a specific zone or not. This is a string with the zone number or null. Only for newly created resources.

For design considerations, limitation and examples of zone-resiliency architecture please refer to Microsoft documentation.

Type: string

Default value: &{}

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idle_timeout

Connection IDLE timeout in minutes (up to 120, defaults to Azure defaults). Only for newly created resources.

Type: number

Default value: &{}

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public_ip

A map defining a Public IP resource.

List of available properties:

create - (bool, required) controls whether a Public IP is created, sourced, or not used at all.
name - (string, optional) name of a created or sourced Public IP, required unless public_ip module and id property are used.
resource_group_name - (string, optional) name of a resource group hosting the sourced Public IP resource, ignored when create = true.
id - (string, optional, defaults to null) ID of the Public IP to associate with the NAT Gateway. Property is used when Public IP Address is not created or sourced within this module.

The module operates in 3 modes, depending on combination of create and name properties:

`create`	`name`	operation
`true`	`!null`	a Public IP resource is created in a resource group of the NAT Gateway
`false`	`!null`	a Public IP resource is sourced from a resource group of the NAT Gateway, the resource group can be

                overridden with `resource_group_name` property

false | null | a Public IP resource will not be created or sourced at all

Example:

# create a new Public IP
public_ip = {
  create = true
  name = "new-public-ip-name"
}

# source an existing Public IP from an external resource group
public_ip = {
  create              = false
  name                = "existing-public-ip-name"
  resource_group_name = "external-rg-name"
}

Type:

object({
    create              = bool
    name                = optional(string)
    resource_group_name = optional(string)
    id                  = optional(string)
  })

Default value: &{}

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public_ip_prefix

A map defining a Public IP Prefix resource.

List of available properties:

create - (bool, required) controls whether a Public IP Prefix is created, sourced, or not used at all.
name - (string, optional) name of a created or sourced Public IP Prefix, required unless public_ip module and id property are used.
resource_group_name - (string, optional) name of a resource group hosting the sourced Public IP Prefix resource, ignored when create = true.
length - (number, optional, defaults to 28) number of bits of the Public IP Prefix, this value can be between 0 and 31 but can be limited on subscription level (Azure default is /28).
id - (string, optional, defaults to null) ID of the Public IP Prefix to associate with the NAT Gateway. Property is used when Public IP Prefix is not created or sourced within this module.

The module operates in 3 modes, depending on combination of create and name properties:

`create`	`name`	operation
`true`	`!null`	a Public IP Prefix resource is created in a resource group of the NAT Gateway
`false`	`!null`	a Public IP Prefix resource is sourced from a resource group of the NAT Gateway, the resource group can be

                overridden with `resource_group_name` property

false | null | a Public IP Prefix resource will not be created or sourced at all

Example:

# create a new Public IP Prefix, default prefix length is `/28`
public_ip_prefix = {
  create = true
  name   = "new-public-ip-prefix-name"
}

# source an existing Public IP Prefix from an external resource group
public_ip = {
  create              = false
  name                = "existing-public-ip-prefix-name"
  resource_group_name = "external-rg-name"
}

Type:

object({
    create              = bool
    name                = optional(string)
    resource_group_name = optional(string)
    length              = optional(number, 28)
    id                  = optional(string)
  })

Default value: &{}

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Purpose​

Usage​

Reference​

Requirements​

Providers​

Resources​

Required Inputs​

Optional Inputs​

Outputs​

Required Inputs details​

name​

resource_group_name​

region​

subnet_ids​

Optional Inputs details​

tags​

create_natgw​

zone​

idle_timeout​

public_ip​

public_ip_prefix​

Purpose

Usage

Reference

Requirements

Providers

Resources

Required Inputs

Optional Inputs

Outputs

Required Inputs details

name

resource_group_name

region

subnet_ids

Optional Inputs details

tags

create_natgw

zone

idle_timeout

public_ip

public_ip_prefix