Terraform Interview Questions | Terraform Scenario Questions | DevOps Interview Series | Terraform

Summary

In this DevOps interview series video, the focus is on Terraform, a popular Infrastructure as Code (IaC) tool known for its platform agnosticism. The interviewee discusses various components created using Terraform, such as resource groups and VMs, and explains the importance of the Terraform state file. They also cover Terraform's features, lifecycle blocks, and the difference between Terraform and other tools like Ansible and Pulumi. The discussion includes handling lost state files, preserving keys, and managing multiple environments, providing a comprehensive overview of Terraform's capabilities and challenges.

Takeaways

• 📝 Terraform is a popular IaC (Infrastructure as Code) tool known for its platform agnosticism, allowing for infrastructure management across various cloud providers such as Azure, GCP, and AWS.
• 🔄 The 'terraform import' command is used to make changes to the configuration of already created resources within Terraform.
• 🗂️ Terraform maintains a state file that tracks the current status of the infrastructure, which can be stored locally or in a remote storage location, and it is crucial for managing resource changes.
• 🔒 The state file may contain sensitive information and should be stored in an encrypted medium to ensure security.
• 😵 Losing the Terraform state file can lead to issues where Terraform assumes resources have not been created and attempts to recreate them, potentially doubling infrastructure costs.
• 🌐 Terraform supports multiple cloud platforms and uses a human-readable configuration language called HCL (HashiCorp Configuration Language).
• 🔍 The 'terraform validate' command checks the syntax of the Terraform files, ensuring that the configuration is correctly formatted according to HCL standards.
• 🔄 The lifecycle block in Terraform allows for managing resource creation, destruction, and changes throughout deployments with arguments like 'create_before', 'prevent_destroy', and 'ignore_changes'.
• 🛠️ The choice between Terraform and Ansible depends on the specific needs of the business; Terraform is better suited for maintaining a steady state, while Ansible is more procedural and dynamic.
• 📦 Pulumi differentiates itself from Terraform by allowing the use of various programming languages instead of being restricted to HCL, catering to developers' language preferences.
• 🚫 Terraform has some drawbacks, such as the lack of error handling, language restrictions, and the inability to generate scripts or import certain resources directly.

Q & A

What is the significance of the video series on DevOps interviews?

The video series focuses on DevOps interviews, providing insights into various tools and practices within the DevOps field, with a special emphasis on Terraform in this particular video. It aims to prepare viewers for potential interview questions and showcase the expertise of the interviewee.

Why is Terraform considered a prominent tool in Infrastructure as Code (IaC)?

Terraform is a prominent IaC tool because it is platform-agnostic, allowing users to manage infrastructure across multiple cloud platforms like Azure, GCP, and AWS, using a human-readable configuration language called HCL.

What is the purpose of the 'terraform import' command?

The 'terraform import' command is used to make changes to the configuration of already created resources within Terraform. It allows users to import existing infrastructure into Terraform's state management system.

Can you explain the role of the state file in Terraform?

The state file in Terraform is crucial as it keeps track of the current status of the infrastructure in relation to the configuration files. It is typically stored locally or in a remote storage location and can include sensitive information, hence it should be stored securely.

What should one do if the Terraform state file is lost?

If the state file is lost, Terraform will not be able to track the existing infrastructure and may attempt to recreate resources, leading to duplication and increased costs. The 'terraform import' command can be used to resolve this issue by re-importing the existing infrastructure into Terraform's state management.

What are some of the main features of Terraform?

Terraform's main features include its ability to manage infrastructure across multiple cloud platforms, the use of the HCL for human-readable configuration, state tracking for resource changes, and the capability to collaborate on infrastructure through version control systems like Git.

What is the full form of 'HCL' used in Terraform?

HCL stands for HashiCorp Configuration Language, which is the domain-specific language used by Terraform to describe infrastructure.

Can you describe the 'terraform validate' command and its purpose?

The 'terraform validate' command is used to perform a syntax check on all Terraform files in a given directory. It ensures that the files are syntactically correct but does not check for formatting issues like spaces, tabs, or comments.

What is the lifecycle block in Terraform and what does it control?

The lifecycle block in Terraform is a nested block within a resource block that contains meta-arguments for managing resource lifecycle operations. It includes arguments like 'create_before', 'destroy', 'prevent_destroy', 'ignore_changes', and 'replace_triggered_by'.

How does Terraform differ from other tools like Ansible or CloudFormation?

Terraform uses a declarative approach, making it ideal for maintaining a steady state in infrastructure or building from scratch. In contrast, Ansible uses a procedural approach, suitable for managing and configuring infrastructure that evolves or changes over time. CloudFormation is specific to AWS and also follows an IaC approach but is not as platform-agnostic as Terraform.

What is the advantage of using Pulumi over Terraform?

Pulumi allows developers to use the programming language of their choice, such as Python, TypeScript, or JavaScript, instead of being restricted to a specific language like HCL in Terraform. This flexibility can be advantageous for developers who prefer working in certain languages.

Can you explain the concept of remote backends in Terraform?

Remote backends in Terraform are used to store the state file in a remote location, making it easier for teams to collaborate. It allows multiple users in different locations to access and share the same state file, ensuring everyone works with the most current state of the infrastructure.

How can one provide variable values at runtime in Terraform?

To provide variable values at runtime in Terraform, one can remove the default values set in the 'variables.tf' file and then supply the values directly when executing the Terraform command.

How can Terraform manage code for multiple environments?

Terraform can manage code for multiple environments using Terraform workspaces, which allow for separate state files for each workspace, and reusable modules, which enable the use of a single directory for configuration files that can be sourced and passed variables as needed.

Why is Terraform referred to as Infrastructure as Code?

Terraform is referred to as Infrastructure as Code because it allows for the creation, management, and deployment of infrastructure using code, specifically the HashiCorp Configuration Language (HCL), making infrastructure provisioning repeatable and version-controlled.

What are some drawbacks of using Terraform that you have encountered?

Some drawbacks of Terraform include the lack of error handling, the requirement to use HCL which may not be familiar to all developers, the inability to import certain resources, no support for script generation, and issues with accessing data from backends through variable files.

Which version of Terraform is currently being used in your organization?

As of the interview, the organization is not using Terraform but is considering adopting it in the future.