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Terraform Utility Modules 0.9.6Last updated in version 0.9.6

Instance Type

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This is a module that can be used to look up a list of EC2 instance types and determine which of them is available in all Availability Zones (AZs) in the current AWS Region. This is useful because certain instance types, such as t2.micro are not available in some of the newer AZs, while t3.micro is not available in some of the older AZs, and if you have code that needs to run on a "small" instance across all AZs in many different regions, you can use this module to automatically figure out which instance type you should use.

Example code

See the instance-type example for working sample code.

Usage

Use the module in your Terraform code, replacing <VERSION> with the latest version from the releases page:

module "path" {
source = "git::git@github.com:gruntwork-io/terraform-aws-utilities.git//modules/instance-type?ref=<VERSION>"

instance_types = ["t2.micro", "t3.micro"]
}

The arguments to pass are:

  • instance_types: A list of instance types to look up in the current AWS region. We recommend putting them in order of preference, as the recommended_instance_type output variable will contain the first instance type from this list that is available in all AZs.

When you run apply, the recommended_instance_type output variable will contain the recommended instance type to use. This will be the first instance type from your instance_types input that is available in all AZs in the current region. If no instance type is available in all AZs, you'll get an error.

For example, as of July, 2020, if you run apply on the code above in eu-west-1, the recommended_instance_type will be t2.micro, as that's available in all AZs in eu-west-1. However, if you run the same code in ap-northeast-2, the recommended_instance_type will be t3.micro, as t2.micro is only available in 2 of the 4 AZs.

Sample Usage

main.tf

# ------------------------------------------------------------------------------------------------------
# DEPLOY GRUNTWORK'S INSTANCE-TYPE MODULE
# ------------------------------------------------------------------------------------------------------

module "instance_type" {

source = "git::git@github.com:gruntwork-io/terraform-aws-utilities.git//modules/instance-type?ref=v0.9.6"

# ----------------------------------------------------------------------------------------------------
# REQUIRED VARIABLES
# ----------------------------------------------------------------------------------------------------

# A list of instance types to look up in the current AWS region. We recommend
# putting them in order of preference, as the recommended_instance_type output
# variable will contain the first instance type from this list that is
# available in all AZs.
instance_types = <list(string)>

}


Reference

Required

instance_typeslist(string)required

A list of instance types to look up in the current AWS region. We recommend putting them in order of preference, as the recommended_instance_type output variable will contain the first instance type from this list that is available in all AZs.