Basic Terraform Commands

1. terraform init

2. terraform init -upgrade

3. terraform plan

4. terraform apply

5. terraform validate

6. terraform fmt

7. terraform destroy

terraform init

Purpose: Initializes a new or existing Terraform configuration. This command prepares the working directory by downloading and installing the required provider plugins and setting up the backend configuration. It’s the first command to run in a new configuration or when setting up an existing configuration in a new environment.

Usage:

terraform init

Details:

• Downloads necessary provider plugins.

• Configures the backend where the state file is stored.

• Ensures the working directory is ready for further commands.

terraform init -upgrade

Purpose: Upgrades the modules and provider plugins to the latest acceptable versions, as defined in the configuration files. This command is useful when you want to ensure that you are using the most recent versions of your providers and modules.

Usage:

terraform init -upgrade

Details:

• Similar to terraform init, but forces the upgrade of all module and provider versions.

• Useful for keeping the infrastructure code up-to-date with the latest features and security patches.

terraform plan

Purpose: Creates an execution plan, showing what actions Terraform will take to achieve the desired state defined in the configuration files. It’s a dry run that doesn’t change any real resources but provides a detailed overview of what will be created, modified, or destroyed.

Usage:

terraform plan

Details:

• Compares the current state with the desired state defined in the configuration files.

• Outputs a detailed plan of changes.

• Helps in understanding the impact of changes before applying them.

terraform apply

Purpose: Applies the changes required to reach the desired state of the configuration. This command executes the plan generated by terraform plan and modifies real infrastructure resources.

Usage:

terraform apply

Details:

• Executes the actions proposed in the terraform plan.

• Prompts for approval before making changes unless the -auto-approve flag is used.

• Modifies, creates, or destroys resources as needed to match the configuration.

terraform validate

Purpose: Validates the configuration files in the directory. It checks the syntax and internal consistency of the files, ensuring that the configurations are well-formed and internally consistent.

Usage:

terraform validate

Details:

• Ensures that configuration files are syntactically correct.

• Detects issues that could prevent Terraform from successfully executing plans and applies.

• Does not interact with remote resources or state.

terraform fmt

Purpose: Formats the configuration files to a canonical format and style. This command helps maintain a consistent code style throughout Terraform configuration files.

Usage:

terraform fmt

Details:

• Reformats configuration files to follow Terraform’s style conventions.

• Enhances readability and maintainability of configuration files.

• Can be run in the current directory or specified directories.

terraform destroy

Purpose: Destroys all resources managed by the Terraform configuration. This command is used to remove all the infrastructure defined in the configuration files.

Usage:

terraform destroy

Details:

• Prompts for confirmation before destroying resources unless the -auto-approve flag is used.

• Completely removes all managed infrastructure.

• Useful for tearing down environments and cleaning up resources.

Understanding Terraform in General

Who are Terraform's Main Competitors?

1. Ansible

• Description: Ansible is an open-source automation tool used for configuration management, application deployment, and task automation.

• Comparison: While Terraform focuses on infrastructure provisioning and maintaining state, Ansible is more oriented towards configuration management and automating operational tasks on existing infrastructure.

2. Packer

• Description: Packer is an open-source tool for creating identical machine images for multiple platforms from a single source configuration.

• Comparison: Packer is often used alongside Terraform. Packer creates the machine images, while Terraform uses those images to provision infrastructure.

3. Cloud Foundry

• Description: Cloud Foundry is an open-source platform-as-a-service (PaaS) that enables developers to build, deploy, and run applications on their cloud infrastructure.

• Comparison: Cloud Foundry abstracts away much of the infrastructure management that Terraform handles, providing a higher-level platform for deploying applications.

4. Kubernetes

• Description: Kubernetes is an open-source container orchestration platform that automates deploying, scaling, and operating containerized applications.

• Comparison: Kubernetes manages the lifecycle of containers and their applications, while Terraform manages the underlying infrastructure that can host Kubernetes clusters and other resources.

Summary

Terraform is an essential tool in modern infrastructure management, enabling Infrastructure as Code (IaC) to automate and streamline the provisioning and management of cloud resources. Understanding and using its basic commands—such as init, plan, apply, validate, fmt, and destroy—is crucial for effectively managing infrastructure.

Competitors like Ansible, Packer, Cloud Foundry, and Kubernetes each serve specific needs within the ecosystem of cloud infrastructure and application management, often complementing Terraform rather than directly competing with it. By understanding the roles of these tools, you can choose the right combination to fit your infrastructure and application management needs.