Terraform is IAAC (infrastructure as a code) tool and is an open-source tool for building, changing, and versioning infrastructure safely and efficiently. It can be used to manage a variety of infrastructure resources. Terraform uses a simple, human-readable language called HashiCorp Configuration Language (HCL) to define infrastructure as code, making it easy to version, collaborate on, and automate the creation and management of infrastructure. Terraform can also be integrated with other tools and services, such as cloud providers and configuration management tools, to provide a comprehensive infrastructure management solution. It can be used to manage resources on different cloud providers like AWS, GCP, Azure, etc. One key feature in terraform is state management.
Importance of IaaC
IAAC stands for Infrastructure as Code, and it plays a crucial role in the DevOps (Development and Operations) methodology. DevOps is an approach that emphasizes collaboration between development and IT operations teams to automate and streamline the software delivery process. Infrastructure as Code is a fundamental concept in achieving the goals of DevOps. Infrastructure as Code is a critical aspect of DevOps as it brings automation, consistency, scalability, and collaboration to infrastructure management, enabling teams to deliver high-quality software more efficiently and reliably.
Why to Use State
In Terraform, state refers to the saved information about your infrastructure managed by Terraform and is a crucial aspect of the infrastructure management process. It is a representation of the current state of the infrastructure managed by Terraform, including resources, configurations, dependencies, and metadata.
The state file in Terraform serves several advantages:
Infrastructure Visibility, Tracking, and Managing Resources
The state file provides a detailed view of the deployed infrastructure. It tracks all the resources provisioned by Terraform, their configurations, and their current status, including their metadata and dependencies. This visibility helps you understand the existing infrastructure and track changes over time. When you apply changes to your infrastructure using Terraform, it compares the desired state (defined in your configuration files) with the current state (stored in the state file) and determines the necessary actions to achieve the desired state. The state file allows Terraform to accurately plan and execute changes, including additions, modifications, and deletions of resources.
Infrastructure Versioning
The state file serves as a record of your infrastructure’s history. It captures the current and previous states, including the changes made over time. This can be valuable for auditing purposes, troubleshooting, or rolling back to a previous state if needed.
Remote State Management
Terraform supports storing the state file remotely, such as in a remote storage backend like Amazon S3 or Terraform Cloud. Storing the state remotely provides additional benefits like better security, concurrent access, and the ability to collaborate across different environments.
Resource Attribute Management
The state file stores the current attribute values of resources. When you make changes to the infrastructure, Terraform references the state file to determine the current values of attributes. This allows Terraform to selectively modify only the necessary attributes, avoiding unnecessary modifications and reducing the risk of unintended consequences.
Dependency Management
The state file also includes information about resource dependencies. It tracks the relationships between resources, such as one resource relying on the existence or properties of another. Terraform uses this information to ensure that resources are created and destroyed in the correct order, maintaining the integrity and consistency of the infrastructure.
Concurrent Collaboration
The state file facilitates collaboration among team members when managing infrastructure. It serves as a shared source of truth, allowing multiple users to work simultaneously on the same infrastructure. Terraform uses a state locking mechanism to prevent conflicts when multiple users attempt to apply changes simultaneously, ensuring consistency and preventing unintended modifications.
Idempotent Infrastructure Management
Terraform uses the state to ensure idempotent infrastructure management. This means that running the same Terraform configuration multiple times will result in the same infrastructure state. Terraform checks the state to see if a resource already exists before creating it, ensuring that changes are only applied when necessary.
State Preservation
By preserving the state file, Terraform can retain knowledge about the infrastructure even if the configuration files are lost. This allows you to manage existing infrastructure, perform updates, and make changes without relying solely on the original configuration files.
How We Use Terraform in Our Projects
Infra/Staging
- Cluster (backend, provider, vpc, subnets, routing tables, cluster, nodegroups)
- Resource(backend, nginx, cert-manager, adminer, database, etc)
Bucket name: Project_name-terraform-state
Rules: block public access, enable versioning
The Remote Backend State File will be Named in the Bucket as follows
- staging_bucket/project/staging/cluster
- staging_bucket/project/staging/resource
- production_bucket/project/production/cluster
- production_bucket/project/production/resources
Some Best Practices for using Terraform
- Use modules for repeatable infrastructure patterns, Use modules to organize your Terraform code and make it more reusable.
- Use version control for all Terraform configuration files.
- Use separate state files for each environment (e.g. development, staging, production)
- Use remote state backend for storing the state file, and lock state with DynamoDB for state file consistency.
- Test your Terraform configurations using tools such as Terratest.
- Use Terraform’s built-in variables to make your code more flexible and easier to maintain.
- Use the “terraform plan” command to preview changes before applying them.
- Use the “terraform validate” command to check for errors in your configuration files.
- Use the “terraform apply -auto-approve” command to speed up the application process.
- Use the “terraform import” command to import existing resources into Terraform.
- Use the “terraform output” command to easily view output values from a Terraform state file.
- Use Terraform’s built-in versioning to track changes to your infrastructure.
- Keep your Terraform version up to date.
- Continuously monitor and validate your infrastructure with automated tooling like Sentinel.
- Distributes resources in separate file for more readability.
Conclusion
In summary, Terraform provides visibility, resource tracking, dependency management, collaboration support, attribute management, and many other features. The state file is a crucial component of Terraform’s infrastructure management workflow, enabling accurate planning, execution of changes, and maintaining the desired state of the infrastructure.
