Understanding DevOps Tools: Ansible and Terraform

Ansible and Terraform – heard about these DevOps tools? This article is all about them and their differences.

Infrastructure as Code (IaC) is a core part of the DevOps domain and is a core skill that DevOps engineers must possess. IaC is used to provision and manage the IT infrastructure using configuration code that is machine-readable definition files. Using this software engineering approach towards operations, you can automate the IT infrastructure using programming scripts.

When a DevOps engineer thinks about automation using code in DevOps, two DevOps tools always get highlighted, Terraform and Ansible. Both are top-rated and widely used tools in the DevOps domain. But many folks are new to these tools and do not know the key differences between them. In this article, I will discuss Terraform, Ansible and their key differences.

What is Terraform?

Terraform is an open-source infrastructure as a code software tool created by HashiCorp. You can orchestrate a complete IT infrastructure by using very easy-to-use declarative language in Terraform. In Terraform, you need to declare and configure the necessary resources for the infrastructure. Then, it will take care of all the required dependencies and build the infrastructure for you.

Terraform launched just a few years ago, in 2014, but the adoption rate of this tool has been fantastic. It offers excellent features that ease the IT infra’s complete orchestration because configuring the whole infrastructure in a big organization is complex. You can also integrate this tool with all popular cloud providers such as AWS, GCP, etc.

Most IT organizations have different working environments for different teams, so development, staging, or QA and production teams will have their separate environments. After a while, it isn’t easy to manage the production environment. To ease the management, organizations use Terraform to codify everything in the production environment. By using terraform, you can spin developer and staging environments very quickly, which will be very similar to the production environment. This helps in developing and testing the application in a similar platform as production. Many big organizations such as Starbucks, Slack, Uber, etc., leverage terraform features big time.

Here are some advantages of Terraform:

• Manages the services using a simple GUI.
• Describes the infrastructure for GCP, AWS, Azure, and others using a straightforward language (declarative).
• Supports role-based access control (RBAC) for security.
• It can be provisioned with OpenStack, Azure, AWS, GCP easily by using their APIs
• It follows masterless architecture, so there is no master node for tracking all the configuration updates.
• Teams within an organization can easily collaborate on the infrastructure using the terraform registry.
• Integration with continuous integration platforms like GitLab, Jenkins, Travis for deploying DevOps pipelines is easy.

What is Ansible?

Ansible is a configuration management tool in the DevOps domain that is used to automate all IT tasks. Ansible is also an open-source tool that uses both declarative and procedural languages for configuration management. This tool has outstanding support from all the popular cloud providers, and it automates the applications, networks, infrastructure, security, containers, etc. It reduces the complexities in the DevOps processes significantly, so many DevOps engineers prefer to use this tool.

Ansible automates the most complex infrastructure with ease by using simple YAML configuration files (human-readable). It uses a code file written in YAML to perform configuration management; this code file is called Ansible Playbook. Ansible is agentless and has a master that pushes all the configurations required to manage and update the applications on the remote servers. In Ansible, you need to use SSH for connecting to the nodes in the IT infrastructure. Once the connection with the node is successful, Ansible pushes the most recent configurations using Ansible modules to install or update or remove the application. You also have options to run ad-hoc commands in Ansible for executing small tasks with speed.

Here are some advantages and features of Ansible:

• As Ansible is agentless, you don’t need to install and run agents on the nodes to perform the tasks.
• As Ansible was built on Python, it has a plethora of libraries to offer in Python, and that is why it is very developer-friendly.
• Provides secure authentication using SSH.
• Ansible Tower gives enterprise-level visualization features.
• The master sends the latest configurations on the remote servers to perform changes in the infrastructure, so it supports a push-based model.
• It uses human-readable YAML files for configuration management, so no additional coding skills are required.

Terraform vs. Ansible: Differences

Orchestration vs. Configuration Management

Ansible is a configuration management tool, and Terraform is an orchestration tool. This is the most fundamental difference between Terraform and Ansible. Although some of the features are common between these tools, they are still different from each other.

Ansible is used to add, update, delete and manage the configuration of the IT infrastructure, whereas Terraform is used to declare infrastructure components and orchestrate them across multiple cloud providers.

Procedural vs Declarative

Terraform uses declarative configuration language to declare the resources of the IT infrastructure. Ansible uses both procedural and declarative languages for configuration management. The procedural way is used in Ansible to run ad-hoc commands and reach the desired infrastructure configuration. The ansible modules use a declarative approach.

Mutable vs. Immutable Infrastructure

You can create mutable infrastructure using Ansible and immutable infrastructure using Terraform. Ansible manages and configures the software of the infrastructure on the same server. When you push more configuration updates, the production environment becomes complex and leads to many bugs that are difficult to identify and fix.

Terraform primarily uses a fresh Docker image for any deployment on the server. Terraform creates a new docker image to update any software on the infrastructure, deploys that image on all the servers, and removes the old configuration docker image. So even after multiple configuration updates, the environment remains stable.

Master vs. Masterless

Ansible has a master machine architecture responsible for storing the complete infrastructure state and pushing the new configuration updates on the remote servers. That is why it is called a push-based deployment model in ansible.

In Terraform, there is no separate master system. However, when it works with cloud providers like GCP, AWS through the APIs, the API server is the master machine in that case.

Community

In comparison, the community of Ansible is stronger than Terraform. For example, Ansible has 45 branches, 49.7K star, 51,836 commits, and 21K forks on GitHub, whereas Terraform has 183 branches, 28.7K star, 28,778 commits, and 6.9K forks. Currently, the community of both tools is growing rapidly.

Which one to choose, Ansible or Terraform?

I would say this is not an apple to apple comparison. The answer to this question depends on the business requirements. You can use Ansible for configuration management add Terraform to orchestrate the IT infrastructure. If your organization works with cloud providers, working with Terraform would be a better option. Both the tools have their limitations and benefits, and both are popular tools in the DevOps domain. So, depending on the problem statement you are trying to solve, you can choose either of the tools.

Here is a comparison table that summarizes the differences between Ansible and Terraform.

Conclusion 👩‍💻

That was all about Ansible, Terraform, and their differences. Both the DevOps tools are highly used in production environments and are often present in most bigger organizations. So, what are you waiting for? Go ahead and choose the tool that is more suitable for your organization’s business requirements. You can start by learning either of the tools, but knowing both gives you an advantage in the diverse industry.