Hardcoding AMI IDs, account IDs, region codes, subnet cidrs and Route53 zone IDs brings duplication into your Terraform code, makes it brittle and prevents you running it in different regions and accounts.
Use this module to dynamically retrieve the CoreOS AMI ID for your region instead of just hardcoding it in.
module coreos_ami_id
{
source = "github.com/devops4me/terraform-aws-coreos-ami-id"
}
resource aws_instance mini
{
ami = "${module.coreos_ami_id.out_ami_id}"
instance_type = "t2.micro"
}
Put the above in a file named foo.tf, go to the directory and run it.
$ terraform init .
$ terraform -auto-approve apply
The CoreOS AMI for HVM virtualization is the assumed default. HVM (hardware virtual machine) makes use of virtualization extensions in hardware and now performs better than paravirtual (PV) machines.
Linux HVM / PV virtualization types - Explained.
module coreos_ami_id
{
source = "github.com/devops4me/terraform-aws-coreos-ami-id"
in_use_pv = "true"
}
To insist on PV set in_use_pv to true but beware that some regions lack a paravirtual CoreOS image.
| Region Name | Region Code |
|---|---|
| Asia Pacific (Seoul) | ap-northeast-2 |
| Asia Pacific (Mumbai) | ap-south-1 |
| Canada (Central) | ca-central-1 |
| China (Ningxia) | cn-northwest-1 |
| EU (London) | eu-west-2 |
| EU (Paris) | eu-west-3 |
| US East (Ohio) | us-east-2 |
out_ami_id is the only output from this module representing the EC2 AMI ID for CoreOS in your AWS region and selected virtualization type.
Just double check that
- you have terraform and git intalled (or Terraform Enterprise)
- your AWS credentials have been installed in the right place/s
- if PV is chosen a CoreOS AMI exists for the region (see above table)
Bug reports and pull requests are welcome on GitHub at the https://github.com/devops4me/terraform-aws-vpc-network page. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
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