10.0 Terraform

What is Terraform?

Terraform is a tool for building, changing, and versioning infrastructure safely and efficiently. Terraform can manage existing and popular service providers as well as custom in-house solutions.

Note

Infrastructure as code (IaC) is an approach to managing IT infrastructure in which infrastructure resources are provisioned and managed using code and software development techniques. The idea behind IaC is to treat infrastructure like software, meaning that it can be version controlled, tested, and deployed in a consistent and repeatable manner.

With IaC, infrastructure resources such as servers, networking, and storage are defined and managed using code, which can be stored in version control systems like Git. This code can then be used to automate the provisioning and management of infrastructure resources, making it easier to maintain consistency, track changes, and quickly deploy and scale resources as needed.

Some benefits of using IaC include:

1. Increased automation: IaC allows for automated deployment and management of infrastructure resources, reducing the need for manual intervention and improving consistency and reliability.

2. Improved scalability: With IaC, infrastructure resources can be easily scaled up or down as needed, making it easier to meet changing business requirements and accommodate growth.

3. Enhanced security: IaC allows for more consistent and standardized security practices, making it easier to identify and remediate security issues.

4. Better collaboration: IaC allows for teams to work more collaboratively since infrastructure resources can be managed using code that can be shared, version controlled, and tested.

Terraform

Note

Terraform is an open-source infrastructure as code (IaC) tool that allows developers to manage and provision cloud infrastructure in a declarative way. It enables teams to define and automate the deployment and configuration of infrastructure resources, including virtual machines, containers, load balancers, and other cloud services.

Terraform uses a domain-specific language (DSL) called HashiCorp Configuration Language (HCL) to define the desired state of infrastructure resources. The HCL code describes the desired configuration of the infrastructure and the dependencies between resources. Terraform then compares the desired state to the current state of the infrastructure and generates a plan for making any necessary changes.

Terraform supports a wide range of cloud providers, including Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform (GCP), and many others. It also supports on-premises infrastructure, such as VMware and OpenStack.

One of the key benefits of using Terraform is that it allows teams to manage infrastructure as code, making it easier to version control, collaborate, and test infrastructure changes. It also enables teams to provision infrastructure quickly and consistently, reducing the risk of configuration drift and human error.

Terraform has become a popular tool for infrastructure automation and is widely used in many organizations, from startups to large enterprises.

Why terraform?

1. Declarative Syntax Terraform uses a declarative configuration language to describe the desired state of your infrastructure. This means you specify what you want to achieve, rather than how to achieve it, allowing Terraform to figure out the steps to take.

2. Infrastructure as Code (IaC) With Terraform, infrastructure is managed through code, which can be versioned, reused, and shared. This approach to infrastructure management brings benefits like consistency, reproducibility, and scalability.

3. Provider Ecosystem Terraform works with a wide range of providers, allowing it to manage resources across multiple cloud platforms (e.g., AWS, Azure, Google Cloud), services (e.g., Kubernetes, Docker), and software products (e.g., GitHub, Datadog). Providers are plugins that implement resource types and understand API interactions.

4. State Management Terraform tracks the state of your infrastructure and mappings between your configuration and real-world resources. This state allows Terraform to plan and make changes to your infrastructure with minimal human intervention. The state can be stored locally or remotely, enabling collaboration and history tracking.

5. Modularity and Reusability Modules in Terraform allow users to encapsulate and reuse configurations. This modularity promotes best practices, reduces duplication, and simplifies management of complex infrastructures.

6. Plan and Apply Workflow Terraform’s workflow consists of two main steps: terraform plan and terraform apply. The plan command generates an execution plan to show what Terraform will do to reach the desired state. The apply command executes the plan to manage the infrastructure resources.

7. Immutability and Infrastructure Lifecycle Terraform encourages immutable infrastructure patterns, where changes are made by replacing resources rather than modifying them in place. This approach can reduce the risk of configuration drift and simplify the rollback of changes.

8. Security Practices Terraform can manage sensitive data, such as passwords or access keys, using variables and securely storing state files. Proper security practices, including state encryption and limiting access to the state file, are crucial.

9. Community and Ecosystem Terraform benefits from a strong community and ecosystem, with a vast amount of documentation, modules, provider plugins, and third-party tools that extend its functionality.

10. Continuous Integration and Deployment (CI/CD) Terraform integrates well with CI/CD pipelines, enabling automated testing, infrastructure provisioning, and deployment within automated workflows, enhancing the DevOps practices.

1. Version Control Integration

   Code as Infrastructure: Terraform configurations are stored in version control systems alongside application code, making it easier to track changes, review infrastructure changes through pull requests, and maintain a history of the infrastructure alongside the application it supports.

2. Automated Testing and Validation

   • Static Code Analysis: Tools like tflint and terraform validate can be used to catch syntax and logical errors in Terraform configurations.

   • Policy as Code: Tools like HashiCorp Sentinel (Terraform Enterprise) or OPA (Open Policy Agent) can enforce policies on Terraform configurations to ensure compliance with organizational standards and security practices.

   • Integration Testing: After applying changes in a non-production environment, automated tests can verify that the infrastructure behaves as expected.

3. Automated Deployment

   • Plan and Apply: In CI/CD pipelines, terraform plan can be executed to show the intended changes, which can be reviewed and approved before terraform apply is automatically run to make the changes.

   • Rollback and Staging: Using multiple environments (dev, staging, production) and Terraform workspaces allows for safe testing and deployment strategies, including the ability to roll back changes if necessary.

4. Collaboration and Review

   Pull Request Workflows: Infrastructure changes through Terraform can be submitted as pull requests, allowing for code review and approval processes similar to application code changes. This promotes collaboration and ensures high-quality infrastructure changes.

Testing Terraform

Testing Terraform involves ensuring that your infrastructure configurations do what you expect them to do before and after applying them. Here are common approaches to testing Terraform configurations:

1. Static Analysis

   Tools like terraform fmt, terraform validate, and tflint help in formatting, validating syntax, and linting Terraform configurations, catching errors early in the development cycle.

2. Unit Testing

   Terratest: A Go library that allows you to write automated tests for your infrastructure code. With Terratest, you can apply and destroy Terraform configurations in a sandbox environment and verify the correctness of the infrastructure using Go test frameworks.

3. Integration Testing

   After deploying resources with Terraform, integration tests can be run to ensure that the deployed infrastructure interacts correctly with other components and services. This can be part of a CI/CD pipeline where automated tests verify network configurations, database connections, etc.

4. End-to-End Testing

   Comprehensive testing that covers the entire system from start to finish, ensuring the infrastructure supports the application’s requirements. Tools like Terratest can also be used for end-to-end testing by simulating real-world scenarios.

5. Compliance and Security Testing

   Checkov, Terrascan, and TFSec: Tools designed to analyze Terraform code for security issues and compliance with best practices. They can automatically detect common security concerns in your Terraform configurations.

Terraform vs competitors | Terraform vs OpenTofu

This year Hashicorp decided to update the license from open source to BUSL. That means that all the side projects built on top of Terraform are now in a legal grey area. OpenTofu is a fork of Terraform that is licensed under the Apache 2.0 license. It is a drop in replacement for Terraform and is 100% compatible with Terraform.

There are several infrastructure-as-a-code (IaaC) tools that are similar to Terraform and can be considered competitors. Here are some of the most popular ones:

1. Pulumi: Pulumi is an open-source infrastructure as code tool that allows developers to define and deploy infrastructure resources using a programming language such as Python, JavaScript, or Go. It is tightly integrated with cloud providers such as AWS, Azure, and GCP and can be used to provision and manage resources in these clouds.

2. CloudFormation: CloudFormation is an IaC tool provided by Amazon Web Services (AWS) that allows developers to define and deploy AWS infrastructure resources using a JSON or YAML file. It is tightly integrated with other AWS services and can be used to provision and manage resources in AWS.

3. SST (Serverless Stack): SST is an open-source framework for building serverless applications. It uses a YAML-based language to define the desired state of infrastructure and can be used to manage servers, networks, and other infrastructure resources.

4. Ansible: Ansible is an open-source automation tool that can be used for infrastructure as code. It uses a YAML-based language to define the desired state of infrastructure and can be used to configure and manage servers, networks, and other infrastructure resources.

5. Chef: Chef is an open-source configuration management tool that can be used for infrastructure as code. It uses a Ruby-based language to define infrastructure as code and can be used to manage servers, applications, and other infrastructure resources.

6. Puppet: Puppet is an open-source configuration management tool that can be used for infrastructure as code. It uses declarative language to define the desired state of infrastructure and can be used to manage servers, applications, and other infrastructure resources.

7. SaltStack: SaltStack is an open-source automation tool that can be used for infrastructure as code. It uses a YAML-based language to define the desired state of infrastructure and can be used to manage servers, networks, and other infrastructure resources.

Getting started

If you’re new to Terraform and want to get started, here are some steps you can follow:

1. Choose a Cloud Provider: Terraform supports a wide range of cloud providers, including AWS, Azure, GCP, and many others. Choose a cloud provider that you want to work with and create an account if you don’t have one already.

2. Create a Basic Terraform Configuration: Create a basic Terraform configuration file that defines the resources you want to create in your cloud provider.

3. Initialize the Terraform Configuration: Once you have created the Terraform configuration file, initialize Terraform by running the terraform init command in the directory containing the configuration file. This command will download the necessary provider plugins and set up the Terraform environment.

4. Plan the Terraform Configuration. Before you apply the Terraform configuration, you can use the terraform plan command to see what changes Terraform will make to your infrastructure. This command will generate a plan that shows what resources will be created, updated, or destroyed.

5. Apply the Terraform Configuration: Once you have initialized Terraform, you can apply the configuration by running the terraform apply command. This command will create the resources defined in the configuration file.

6. Manage the Terraform State: Terraform maintains a state file that tracks the current state of your infrastructure. It is important to manage this state file carefully, as it is used to determine what changes need to be made to your infrastructure. You can use Terraform commands like ‘terraform plan’ and ‘terraform destroy’ to manage the state and make changes to your infrastructure.

Managing state

1. Local Backend

   Description: The default method where Terraform stores state as a plain JSON file on your local filesystem. Use Cases: Suitable for individual use or quick prototypes where remote state management is not required.

2. Remote Backends

   Remote backends store state in a remote data store, supporting team collaboration, state locking, and secure storage.

   2.1 HashiCorp Terraform Cloud and Enterprise

   Description: Offers advanced features like remote operations, team access controls, and a UI for managing Terraform runs. Use Cases: Ideal for teams needing collaboration, governance, and a robust workflow around Terraform operations.

   2.2 Amazon S3 with DynamoDB for Locking

   Description: Uses Amazon S3 for state storage and DynamoDB for state locking and consistency checking. Use Cases: Suitable for AWS-based infrastructure with requirements for high availability and distributed access.

   2.3 Google Cloud Storage (GCS)

   Description: Utilizes Google Cloud Storage for storing state files, with built-in versioning and locking capabilities. Use Cases: Recommended for infrastructure deployed on Google Cloud Platform (GCP).

   2.4 Azure Blob Storage

   Description: Leverages Azure Blob Storage for state storage, supporting versioning and optional state locking with Azure Blob Storage’s leasing mechanism. Use Cases: Best for teams deploying resources on Microsoft Azure.

   2.5 Consul

   Description: Utilizes HashiCorp’s Consul for storing state data, providing high availability and datacenter replication features. Use Cases: Suitable for dynamic and service-oriented architectures, especially those already using Consul for service discovery.

3. Other Remote Backends

   • Artifactory: Can be used to store state files in an Artifactory repository.

   • etcd, etcdv3: Key-Value stores suitable for storing state in distributed systems.

   • Swift: The object storage service in OpenStack, useful for teams using OpenStack for their cloud infrastructure.

4. State Locking Mechanisms

   Many remote backends support state locking, which prevents concurrent runs from making simultaneous changes to the same state, reducing the risk of state corruption.

5. Encryption at Rest and in Transit

   When choosing a backend, consider whether it supports encryption at rest and in transit to secure sensitive data in your state files.

AWS Managed state

Step 1: Create an S3 Bucket for Terraform State

• Log in to the AWS Management Console and navigate to the S3 service.

• Create a new bucket with a unique name. Ensure the bucket is created in the region where you plan to deploy your resources. Remember to follow best practices for naming and organizing your resources.

• Enable versioning on the bucket to keep the history of your Terraform states. This can be useful for rolling back to a previous state if needed.

Step 2: Create a DynamoDB Table for State Locking

• Navigate to the DynamoDB service in the AWS Management Console.

• Create a new table with a primary key named LockID of type String. The table name can be anything, but it should be indicative of its purpose, such as terraform-state-lock. Note the table settings but you don’t need to add any sort keys or modify the default settings unless your specific use case requires it.

Step 3: Configure Your Terraform Backend

In your Terraform configuration, define the backend to use Amazon S3 for storing the state file and DynamoDB for locking. Add a backend configuration block to your Terraform configuration file (main.tf or a dedicated backend configuration file):

terraform {
backend "s3" {
    bucket         = "your-terraform-state-bucket-name"
    key            = "state-file-name.tfstate"
    region         = "aws-region"
    dynamodb_table = "terraform-state-lock"
    encrypt        = true
    }
}

Step 4: Initialize Terraform with the New Backend

Run terraform init in your project directory. Terraform will prompt you to confirm that you want to copy your state to the new backend. Confirm the action. This command initializes Terraform with the specified backend configuration. If you have existing state, Terraform will ask if you want to migrate that state to the new backend.

Best Practices and Considerations

• Security: Ensure that the AWS IAM role or user you’re using has the necessary permissions to access the S3 bucket and DynamoDB table.

• Encryption: Enabling encryption for the S3 bucket helps protect your state files. The encrypt attribute in the backend configuration ensures that your state files are encrypted at rest.

• Access Control: Use IAM policies to control who can access your Terraform state files. Be cautious with these permissions to prevent unauthorized access.

• State File Sensitivity: Terraform state files can contain sensitive data. Make sure that access to the S3 bucket and DynamoDB table is restricted according to your organization’s security policies.

Terraform Managed state

Step 1: Sign Up and Create an Organization in Terraform Cloud

• Sign Up: If you haven’t already, sign up for an account on Terraform Cloud.

• Create an Organization: After logging in, create an organization. This organization will be used to manage your workspaces and Terraform states.

Step 2: Create a Workspace

• New Workspace: In your organization, create a new workspace. Choose a name that represents your project or the environment you’re managing (e.g., dev, prod).

• Version Control: Optionally, you can connect your workspace to a VCS (Version Control System) repository. This step is not required for state storage but is useful for CI/CD workflows.

Step 3: Configure Terraform to Use Terraform Cloud

Terraform Configuration: In your Terraform configuration, you need to add a backend block that specifies Terraform Cloud as the backend for state storage. This is done in your Terraform configuration files (e.g., main.tf).

terraform {
backend "remote" {
    hostname     = "app.terraform.io"
    organization = "<YOUR_ORGANIZATION_NAME>"

    workspaces {
    name = "<YOUR_WORKSPACE_NAME>"
    }
}
}

Initialization: Run terraform init in your project directory. Terraform will initialize the project, which includes setting up the remote backend. You might be prompted to migrate your existing state to Terraform Cloud during this process.

Step 4: Authenticate Terraform with Terraform Cloud

To authenticate your Terraform CLI with Terraform Cloud, you have several options:

1. Terraform CLI Configuration File: You can use a Terraform CLI configuration file (.terraformrc or terraform.rc) with a credentials block to store your Terraform Cloud token. .. code-block:: python

credentials “app.terraform.io” { token = “your-terraform-cloud-token” }

2. Environment Variable: Alternatively, you can set the TF_CLI_CONFIG_FILE environment variable to the path of your Terraform CLI configuration file or use export TERRAFORM_CONFIG=”/path/to/.terraformrc”.

3. Directly in the Terminal: For a one-time operation, you might also use the terraform login command, which prompts you to enter your Terraform Cloud user token and automatically stores it in your Terraform CLI configuration file.