Understanding the Key Differences Between Terraform and Ansible

Ansible and Terraform are both used to automate repetitive tasks that typically take system administrators hundreds of hours a month to perform manually. Yet many companies still are not taking advantage of these Infrastructure as Code (IaC) tools, which can release system administrators from laboring over manual procedures.

Without IaC tools, system administrators must manually configure servers, release new versions of applications on dozens of servers, install security updates to servers and applications, conduct backups and system reboots, create users, assign permissions for individuals and groups, and document the latest server configurations and steps for installing applications. Many companies still spend countless hours each week doing these tasks, but they all can be automated with software like Terraform and Ansible.

In this article, we’ll help you understand the benefits of Terraform and Ansible, as well as the key ways they differ from one another. But first, let’s define what each of these software solutions was designed to do.

What is Ansible?

Ansible is a collection of open source software tools that automate configuration management, software provisioning, intra-service orchestration, server updating, and many other routine IT tasks. Written in Python, Ansible is easy to deploy, making it a popular option for organizations looking to streamline version control. It does not require extensive programming knowledge to understand, which is advantageous to end-users as well as DevOps teams. First released in 2012 and acquired by Red Hat in 2015, Ansible can configure systems, deploy software, and orchestrate advanced workflows to support application deployment, system updates, and more. It also supports hybrid cloud automation, network automation, and security automation. Automation streamlines essential routine activities and tests and deploys network changes, helping you run your network more efficiently.

Strengths and Weaknesses

Ansible Automation Platform is agentless, scalable and easy to install and configure. It has an extensive library of community content via the Ansible Galaxy portal. Though there are few barriers to learning the essentials of Ansible, developers frequently cite the tool’s lack of UI and sub-par Windows support as sources of frustration. It should be noted that Ansible 2.8 contains SSH connectivity for Windows-managed nodes as an experimental feature, suggesting that there is plenty of untapped potential in this solution.

What is Terraform?

Written in Go, Terraform is an open source solution for securely building and maintaining IaC processes. It has the ability to manage proprietary infrastructure solutions as well as other solutions provided by third-party vendors. Terraform-managed infrastructure can be hosted on leading public clouds like Amazon Web Services (AWS), Google Cloud and Microsoft Azure. Alternatively, it can be hosted on-premises using private clouds. Terraform is commonly leveraged by IT departments and DevOps teams to ensure a single, secure workflow across multiple cloud environments. It was created by HashiCorp and uses the company’s declarative HashiCorp Configuration Language (HCL), a JSON compatible language that adds features to help you use the Terraform tool to its highest potential. Terraform is also commonly used for managing Kubernetes clusters and multicloud deployments and for automating the infrastructure deployment of existing workflows.

Strengths and Weaknesses

As mentioned above, Terraform supports stable configurations for just about any cloud or data service provider. This helps facilitate cross-platform development and/or workflows. The declarative HashiCorp Configuration Language (HCL) makes it easy to define and provision complex IT infrastructure. However, learning HCL or Terraform’s JSON-compatible alternative syntax can be challenging for beginners.

Key Differences Between Ansible and Terraform

1.    Modules and General Approach

While Terraform relies on a declarative approach that involves explicitly defining the end state and then automating the steps required to achieve this goal, Ansible uses a hybrid approach that incorporates both procedural and declarative configurations. This can create a more flexible development ecosystem, but it also involves more human input throughout the process.

A good example of this is the way each tool deploys modules. With Ansible, each module performs a specific task. Automating a process across multiple endpoints requires that the best-suited module first be manually identified, configured and executed. Users can program custom modules with a variety of programming languages or can access pre-existing community-generated modules in the Ansible Project. Terraform modules prioritize reusing resources that the developer has grouped together.  

2.    Readability and Ease of Use

Based on the breakdown above, it may seem as though Ansible is the more complicated option to manage and deploy, but this is not the case. Ansible is written in Python and is known for its readable code. Ansible can be easily set up and deployed using widely available Python libraries, making it a more accessible option for beginners. On the flip side, Terraform requires a working knowledge of HCL or its JSON-compatible alternative syntax.

3.    Available Features & Capabilities

For those willing to put the time into mastering its intricacies, Terraform offers several powerful features, including lifecycle management capabilities, simplified rollbacks and easy integrations within existing CI/CD pipelines. The best part? While similarly powerful IaC solutions like AWS CloudFormation and Azure Resource Manager are typically restricted to their own platform, Terraform can be deployed simultaneously across different cloud platforms and architectures.

Ansible’s primary selling point, outside of perhaps its accessibility and ease of use, is the fact that it executes tasks in order independently of any dependency system. Processes are stopped immediately upon the identification of an error.

Both tools provide access to a robust—and growing—online community that can be leaned upon for modules, user documentation, reusable roles, configurations and troubleshooting assistance.

Which tool is better? The answer depends on what you’re trying to accomplish.

Terraform’s platform-agnostic software is great for organizations that want to streamline the way they securely collaborate across different environments and/or transition to multi-cloud infrastructure management. It is also useful for developing multi-tier applications and has a superior UI.

Ansible is a great option with a low barrier to entry. IT departments across the globe rely on it to automate day-to-day tasks related to cloud provisioning, infrastructure provisioning, application deployment and enterprise-grade security.

What does all this mean for IT professionals?

Whether you opt to obtain certification in Ansible Essentials or learn the basics of Terraform, focusing on Infrastructure as Code will have you and your company well-positioned for success in today’s cloud-oriented IT ecosystem. To learn more about other skills associated with IaC, check out How to Create an Automated CI/CD Pipeline.