hashicorp / terraform-aws-consul

A Terraform Module for how to run Consul on AWS using Terraform and Packer
Apache License 2.0
401 stars 487 forks source link

DISCLAIMER

This repository is no longer supported, please consider using this repository for the latest and most supported version for Consul.

Moving forward in the future this repository will be no longer supported and eventually lead to deprecation. Please use our latest versions of our products moving forward or alternatively you may fork the repository to continue use and development for your personal/business use.


Consul AWS Module

This repo contains a set of modules in the modules folder for deploying a Consul cluster on AWS using Terraform. Consul is a distributed, highly-available tool that you can use for service discovery and key/value storage. A Consul cluster typically includes a small number of server nodes, which are responsible for being part of the consensus quorum, and a larger number of client nodes, which you typically run alongside your apps:

Consul architecture

How to use this Module

This repo has the following folder structure:

To deploy Consul servers for production using this repo:

  1. Create a Consul AMI using a Packer template that references the install-consul module. Here is an example Packer template.

    If you are just experimenting with this Module, you may find it more convenient to use one of our official public AMIs. Check out the aws_ami data source usage in main.tf for how to auto-discover this AMI.

    WARNING! Do NOT use these AMIs in your production setup. In production, you should build your own AMIs in your own AWS account.

  2. Deploy that AMI across an Auto Scaling Group using the Terraform consul-cluster module and execute the run-consul script with the --server flag during boot on each Instance in the Auto Scaling Group to form the Consul cluster. Here is an example Terraform configuration to provision a Consul cluster.

To deploy Consul clients for production using this repo:

  1. Use the install-consul module to install Consul alongside your application code.
  2. Before booting your app, execute the run-consul script with --client flag.
  3. Your app can now use the local Consul agent for service discovery and key/value storage.
  4. Optionally, you can use the install-dnsmasq module for Ubuntu 16.04 and Amazon Linux 2 or setup-systemd-resolved for Ubuntu 18.04 and Ubuntu 20.04 to configure Consul as the DNS for a specific domain (e.g. .consul) so that URLs such as foo.service.consul resolve automatically to the IP address(es) for a service foo registered in Consul (all other domain names will be continue to resolve using the default resolver on the OS).

What's a Module?

A Module is a canonical, reusable, best-practices definition for how to run a single piece of infrastructure, such as a database or server cluster. Each Module is created using Terraform, and includes automated tests, examples, and documentation. It is maintained both by the open source community and companies that provide commercial support.

Instead of figuring out the details of how to run a piece of infrastructure from scratch, you can reuse existing code that has been proven in production. And instead of maintaining all that infrastructure code yourself, you can leverage the work of the Module community to pick up infrastructure improvements through a version number bump.

Who created this Module?

These modules were created by Gruntwork, in partnership with HashiCorp, in 2017 and maintained through 2021. They were deprecated in 2022 in favor of newer alternatives (see the top of the README for details).

Code included in this Module:

How is this Module versioned?

This Module follows the principles of Semantic Versioning. You can find each new release, along with the changelog, in the Releases Page.

During initial development, the major version will be 0 (e.g., 0.x.y), which indicates the code does not yet have a stable API. Once we hit 1.0.0, we will make every effort to maintain a backwards compatible API and use the MAJOR, MINOR, and PATCH versions on each release to indicate any incompatibilities.

License

This code is released under the Apache 2.0 License. Please see LICENSE and NOTICE for more details.

Copyright © 2017 Gruntwork, Inc.