Oracle Cloud Infrastructure (OCI) Subnet Module for Terraform

Introduction

This module provides a way to provision a Subnet(s) and set the related configuration options in Oracle Cloud Infrastructure (OCI). This serves as a foundational component in an OCI environment.

Solution

Subnets are the home for many IP-based resources in OCI. Much like a VLAN in traditional on-prem LANs.

Resource	Created by Default?
Subnet(s)	No

Prerequisites

This module does not create any dependencies or prerequisites (these must be created prior to using this module):

• VCN
• Security List(s)
  • The network_security module may be used to create and manage Security Lists.
• Route Table
  • Often times only a couple of routing policies exist and are created in the network module.
• DHCP Options
  • Often times only a couple of DHCP Options (DNS profiles) exist and are created in the network module.

Getting Started

Several fully-functional examples have been provided in the examples directory. Refer to the README.md in each example directory for directions specific to each example.

To get started quickly, for the minimum deployment, you can use the following example:

module "oci_subnets" {
  source          = "https://github.com/oracle-terraform-modules/terraform-oci-tdf-subnet.git"
  
  default_compartment_id  = var.default_compartment_id
  vcn_id                  = oci_core_vcn.this.id
  vcn_cidr                = oci_core_vcn.this.cidr_block
  
  subnets = {}
}

This will deploy a Subnet using the module defaults. Review this README for a detailed description of these parameters.

Accessing the Solution

This core service module is typically used at deployment, with no further access required; you might need to access a bastion, if it's been requested to be created as a part of the solution.

You may continue to manage the deployed environment using Terraform (best), the OCI CLI, the OCI console (UI), directly via the API, etc.

Resource-specific inputs

Provider

The following IAM attributes are available in the the terraform.tfvars file:

### PRIMARY TENANCY DETAILS

# Get this from the bottom of the OCI screen (after logging in, after Tenancy ID: heading)
primary_tenancy_id="<tenancy OCID"
# Get this from OCI > Identity > Users (for your user account)
primary_user_id="<user OCID>"

# the fingerprint can be gathered from your user account (OCI > Identity > Users > click your username > API Keys fingerprint (select it, copy it and paste it below))
primary_fingerprint="<PEM key fingerprint>"
# this is the full path on your local system to the private key used for the API key pair
primary_private_key_path="<path to the private key that matches the fingerprint above>"

# region (us-phoenix-1, ca-toronto-1, etc)
primary_region="<your region>"

### DR TENANCY DETAILS

# Get this from the bottom of the OCI screen (after logging in, after Tenancy ID: heading)
dr_tenancy_id="<tenancy OCID"
# Get this from OCI > Identity > Users (for your user account)
dr_user_id="<user OCID>"

# the fingerprint can be gathered from your user account (OCI > Identity > Users > click your username > API Keys fingerprint (select it, copy it and paste it below))
dr_fingerprint="<PEM key fingerprint>"
# this is the full path on your local system to the private key used for the API key pair
dr_private_key_path="<path to the private key that matches the fingerprint above>"

# region (us-phoenix-1, ca-toronto-1, etc)
dr_region="<your region>"

Subnet

The Subnet input variable represents a map of attributes. The automation creates the following resources with the following attributes:

Attribute	Data Type	Required	Default Value	Valid Values	Description
default_compartment_id	string	yes	none	string of the compartment OCID	This is the default OCID that will be used when creating objects (unless overridden for any specific object). This needs to be the OCID of a pre-existing compartment (it will not create the compartment.
vcn_id	string	yes	N/A (no default)	VCN OCID	The OCID of the VCN in which the subnet(s) are to be created.
vcn_cidr	string	no	N/A (no default)	CIDR	The CIDR used by the VCN. This is only needed when dynamically generating subnet CIDRs.
define_tags	map(string)	no	N/A (no default)	The defined tags
freeform_tags	map(string)	no	N/A (no default)	The freeform_tags

subnets

Each entry's key specifies the name to be given to the subnet, with its attributes specified as values in a sub-map.

Key	Data Type	Default Value	Valid Values	Description
compartment_id	string	null	Compartment OCID	Pre-existing compartment OCID (if default compartment is not to be used). If this value is null, the default compartment OCID will be used.
define_tags	map(string)	no	N/A (no default)	The defined tags
freeform_tags	map(string)	no	N/A (no default)	The freeform_tags
dynamic_cidr	bool	false	true/false	Whether or not the CIDR should be dynamically calculated (true) or statically set (false).
cidr	string	static cidr: null, dynamic_cidr: VCN CIDR	IPv4 CIDR	If dynamic_cidr is true, the CIDR specified here will be used in the subnet calculation. If dynamic_cidr is false, the CIDR specified here will be the one used by the subnet.
cidr_len	number	28	Any number between 16 and 30	Number of bits in the subnet mask. Only applicable if dynamic_cidr is true.
cidr_num	number	Defaults to the index number of the subnet being defined	number	zero-indexed network number use for the subnet. For example, 192.168.0.0/16 and cidr_len is 24. For cidr_num of 1, a dynamically generated CIDR of 192.168.1.0/24 would be given. A cidr_num of 0, 192.168.0.0/24 would result and cidr_num of 240 would yield 192.168.240.0/24.
enable_dns	bool	true	true/false	Whether or not DNS should be enabled for the subnet.
dns_label	string	"vcn"	Valid DNS name.	Specify the DNS label to be used for the VCN. If this value is null, a dynamically generated value of subnet<index_num> will be used. For example, the third subnet definition, if DNS is enabled, but no dns_label is provided (a null value is given), a value of subnet2 will be generated (remembering that index numbers are zero-indexed).
private	bool	true	true/false	If set to true, the subnet will be a private subnet. If set to false, a public subnet will be created.
ad	number	null	null, 0, 1 or 2 (dependent upon the number of available Availability Domains (ADs)	For a regional subnet value should be set to null. Number (zero-index, meaning AD1 = 0, AD2 = 1, AD3 = 2) to create an AD-specific subnet.
dhcp_options_id	string	null	null or OCID	Specify the OCID of the DHCP Options to use for the subnet.
route_table_id	string	null	null or OCID	Specify the OCID of the Route Table to use for the subnet.
security_list_ids	list of strings	null	null or list of OCID(s)	Specify the OCID(s) of the Security List(s) to use for the subnet, in list form.

Example The following example creates two subnets, test1 and test2.

module "oci_subnets" {
  ... /snip - shortened for brevity...

  default_compartment_id  = var.default_compartment_id
  # vcn_id = data.terraform_remote_state.network.outputs.vcn.id
  vcn_id                  = oci_core_vcn.this.id
  vcn_cidr                = oci_core_vcn.this.cidr_block
  
  subnets = {
    test1 = {
      compartment_id    = null
      defined_tags      = null
      freeform_tags     = null
      dynamic_cidr      = false
      cidr              = "192.168.0.0/30"
      cidr_len          = null
      cidr_num          = null
      enable_dns        = true
      dns_label         = "test1"
      private           = true
      ad                = null
      dhcp_options_id   = null
      route_table_id    = null
      security_list_ids = null
    },
    test2 = {
      compartment_id    = null
      defined_tags      = null
      freeform_tags     = null
      dynamic_cidr      = false
      cidr              = "192.168.0.4/30"
      cidr_len          = null
      cidr_num          = null
      enable_dns        = true
      dns_label         = "test2"
      private           = true
      ad                = 0
      dhcp_options_id   = null
      route_table_id    = null
      security_list_ids = null
    }
  }
}

Outputs

A map containing each subnet is returned in the subnets output. The outer map key is the name of the subnet, with all subnet attributes (as a map) being returned as the value.

Notes/Issues

• Note that if you provide any single element in the different resource maps (subnets), you must provide all of them. Maps do not have a notion of an optional (or default value) for keys within the map, requiring that all keys/values be passed (if one key is passed, all keys must be passed).

Release Notes

See release notes for release notes information.

URLs

• https://www.terraform.io/docs/providers/oci/r/core_subnet.html

Contributing

This project is open source. Oracle appreciates any contributions that are made by the open source community.

License

Copyright (c) 2020 Oracle and/or its affiliates.

Licensed under the Universal Permissive License v 1.0 as shown at https://oss.oracle.com/licenses/upl.

See LICENSE for more details.