Use Cases of Terraform
We can specify some use-cases which can help you with the applications of Terraform as an IaC solution:
Heroku App Setup
Terraform can be used to codify the setup required for a Heroku application, ensuring that all the required add-ons are available, but it can go even further: configuring DNSimple to set a CNAME, or setting up Cloudflare as a CDN for the app. Best of all, Terraform can do all of this in under 30 seconds without using a web interface.
Multi-tier Applications
A very common pattern is the N-tier architecture. The most common 2-tier architecture is a pool of web servers that use a database tier. Additional tiers get added for API servers, caching servers, routing meshes, etc. This pattern is used because the tiers can be scaled independently and provide a separation of concerns.
Terraform is an ideal tool for building and managing these infrastructures. Each tier can be described as a collection of resources, and the dependencies between each tier are handled automatically; Terraform will ensure the database tier is available before the web servers are started and that the load balancers are aware of the web nodes. Each tier can then be scaled easily using Terraform by modifying a single count configuration value. Because the creation and provisioning of a resource is codified and automated, elastically scaling with load becomes trivial.
Disposable Environments
It is common practice to have both a production and staging or QA environment. These environments are smaller clones of their production counterpart, but are used to test new applications before releasing in production. As the production environment grows larger and more complex, it becomes increasingly onerous to maintain an up-to-date staging environment.
Using Terraform, the production environment can be codified and then shared with staging, QA or dev. These configurations can be used to rapidly spin up new environments to test in, and then be easily disposed of. Terraform can help tame the difficulty of maintaining parallel environments, and makes it practical to elastically create and destroy them.
Multi-cloud Deployments
It’s often attractive to spread infrastructure across multiple clouds to increase fault-tolerance. By using only a single region or cloud provider, fault tolerance is limited by the availability of that provider. Having a multi-cloud deployment allows for more graceful recovery of the loss of a region or entire provider.
Realizing multi-cloud deployments can be very challenging as many existing tools for infrastructure management are cloud-specific. Terraform is cloud-agnostic and allows a single configuration to be used to manage multiple providers, and to even handle cross-cloud dependencies. This simplifies management and orchestration, helping operators build large-scale multi-cloud infrastructures.