[Terraform](/intro/index.html) is HashiCorp’s infrastructure as code tool. It lets you define infrastructure resources in human-readable configuration files that you can version, reuse, and share. Terraform uses the configuration to safely and efficiently provision and manage your infrastructure throughout its lifecycle.
Provisioning infrastructure across multiple clouds increases fault-tolerance, allowing for more graceful recovery from cloud provider outages. However, multi-cloud deployments add complexity because each provider has its own interfaces, tools, and workflows. Terraform lets you use the same workflow to manage multiple providers and handle cross-cloud dependencies. This simplifies management and orchestration for large-scale, multi-cloud infrastructures.
- Try the [Deploy Federated Multi-Cloud Kubernetes Clusters](https://learn.hashicorp.com/tutorials/terraform/multicloud-kubernetes) tutorial on HashiCorp Learn to provision Kubernetes clusters in both Azure and AWS environments, configure Consul federation with mesh gateways across the two clusters, and deploy microservices across the two clusters to verify federation.
- Browse the [Terraform Registry](https://registry.terraform.io/browse/providers) to find thousands of publicly available providers.
You can use Terraform to efficiently deploy, release, scale, and monitor infrastructure for multi-tier applications. N-tier application architecture lets you scale application components independently and provides a separation of concerns. An application could consist of a pool of web servers that use a database tier, with additional tiers for API servers, caching servers, and routing meshes. Terraform allows you to manage the resources in each tier together, and automatically handles dependencies between tiers. For example, Terraform will deploy a database tier before provisioning the web servers that depend on it.
- Try the [Automate Monitoring with the Terraform Datadog Provider](https://learn.hashicorp.com/tutorials/terraform/datadog-provider?in=terraform/applications) tutorial on HashiCorp Learn to deploy a demo Nginx application to a Kubernetes cluster with Helm and install the Datadog agent across the cluster. The Datadog agent reports the cluster health back to your Datadog dashboard, and you will create a monitor for this cluster in Terraform.
- Try the [Use Application Load Balancers for Blue-Green and Canary Deployments](https://learn.hashicorp.com/tutorials/terraform/blue-green-canary-tests-deployments) tutorial on HashiCorp Learn. You will provision the blue and green environments, add feature toggles to your Terraform configuration to define a list of potential deployment strategies, conduct a canary test, and incrementally promote your green environment.
At a large organization, your centralized operations team may get many repetitive infrastructure requests. You can use Terraform to build a "self-serve" infrastructure model that lets product teams manage their own infrastructure independently. You can create and use Terraform modules that codify the standards for deploying and managing services in your organization, allowing teams to efficiently deploy services in compliance with your organization’s practices. Terraform Cloud can also integrate with ticketing systems like ServiceNow to automatically generate new infrastructure requests.
- Try the [Use Modules from the Registry](https://learn.hashicorp.com/tutorials/terraform/module-use?in=terraform/modules) tutorial on HashiCorp Learn to get started using public modules in your Terraform configuration.
Try the [Build and Use a Local Module](https://learn.hashicorp.com/tutorials/terraform/module-create?in=terraform/modules) tutorial on HashiCorp Learn to create a module to manage AWS S3 buckets.
- Follow these [ServiceNow Service Catalog Integration Setup Instructions](/cloud-docs/integrations/service-now) to connect ServiceNow to Terraform Cloud.
Terraform can help you enforce policies on the types of resources teams can provision and use. Ticket-based review processes are a bottleneck that can slow down development. Instead, you can use Sentinel, a policy-as-code framework, to automatically enforce compliance and governance policies before Terraform makes infrastructure changes. Sentinel is available with the [Terraform Cloud team and governance](https://www.hashicorp.com/products/terraform/pricing) plan.
- Try the [Control Costs with Policies](https://learn.hashicorp.com/tutorials/terraform/cost-estimation) tutorial on HashiCorp Learn to estimate the cost of infrastructure changes and define policy to check to limit it.
- The [Sentinel documentation](/docs/cloud/sentinel/index.html) provides more in-depth information and a list of example policies that you can adapt for your use cases.
## PaaS Application Setup
Platform as a Service (PaaS) vendors like Heroku allow you to create web applications and attach add-ons, such as databases or email providers. Heroku can elastically scale the number of dynos or workers, but most non-trivial applications need many add-ons and external services. You can use Terraform to codify the setup required for a Heroku application, configure a DNSimple to set a CNAME, and set up Cloudflare as a Content Delivery Network (CDN) for the app. Terraform can quickly and consistently do all of this without a web interface.
### Resources
Try the [Deploy, Manage, and Scale a an Application on Heroku](https://learn.hashicorp.com/tutorials/terraform/heroku-provider?in=terraform/applications) tutorial on HashiCorp Learn to use Terraform to manage an application’s lifecycle.
Terraform can interact with Software Defined Networks (SDNs) to automatically configure the network according to the needs of the applications running in it. This lets you move from a ticket-based workflow to an automated one, reducing deployment times.
For example, when a service registers with [HashiCorp Consul](https://www.consul.io/), [Consul-Terraform-Sync](https://www.consul.io/docs/nia) can automatically generate Terraform configuration to expose appropriate ports and adjust network settings for any SDN that has an associated Terraform provider. Network Infrastructure Automation (NIA) allows you to safely approve the changes that your applications require, without having to manually translate tickets from developers into the changes you think their applications need.
Try the [Consul-Terraform-Sync Run Modes and Status Inspection ](https://learn.hashicorp.com/tutorials/consul/consul-terraform-sync-run-and-inspect?in=consul/network-infrastructure-automation) tutorial on HashiCorp Learn to learn the different run modes available with Consul-Terraform-Sync, how to monitor the task status, and how to locate or store the Terraform state files in the Consul backend.
Kubernetes is an open-source workload scheduler for containerized applications. Terraform enables you to both deploy the Kubernetes cluster and manage its resources (e.g., pods, deployments, services, etc.). You can also use the [Kubernetes Operator for Terraform](https://github.com/hashicorp/terraform-k8s) to manage cloud and on-prem infrastructure through a Kubernetes custom resource definition (CRD) and Terraform Cloud.
### Resources
- Try the [Manage Kubernetes Resources via Terraform](https://learn.hashicorp.com/tutorials/terraform/kubernetes-provider?in=terraform/kubernetes) tutorial on HashiCorp Learn. You will use Terraform to schedule and expose a NGINX deployment on a Kubernetes cluster.
- Try the [Deploy Infrastructure with the Terraform Cloud Operator for Kubernetes](https://learn.hashicorp.com/tutorials/terraform/kubernetes-operator) tutorial on HashiCorp Learn. You will configure and deploy the Operator to a Kubernetes cluster and use it to create a Terraform Cloud workspace and provision a message queue for an example application.
## Parallel Environments
You may have staging or QA environments that you use to test new applications before releasing them in production. As the production environment grows larger and more complex, it can be increasingly difficult to maintain an up-to-date environment for each stage in the development process. Terraform lets you rapidly spin up and decommission infrastructure for development, test, QA, and production. Using Terraform to create disposable environments as needed is more cost-efficient than maintaining each one indefinitely.
## Software Demos
You can use Terraform to create, provision, and bootstrap a demo on various cloud providers. This lets end users easily try the software on their own infrastructure and even enables them to adjust parameters like cluster size to more rigorously test tools at any scale.
