Introduction

The DevOps environment stresses automation and orchestration for ease of deployment or redeployment on different infrastructure. Two of the most important tools that help in achieving the same are Terraform and Ansible. Both are tools that help in automating configurations and deploying infrastructure. Terraform in particular allows you to deploy infrastructure as a code (IaaC), helping massively in understanding the infrastructure or in other words readability and lift and shift deployments. Ansible on the other hand is a configuration management solution that helps in automating systems configuration and management using IaaC.

Let’s first understand each of them better before we dive into their differences and advantages over each other.

  1. Understanding Terraform
  2. Understanding Ansible
  3. Let’s now dive into the differences between Terraform vs Ansible.

1) Understanding Terraform

Terraform is an open-source Infrastructure as a Code solution, developed by HashiCorp and release in 2014. The code that describes the infrastructure is declarative in nature, meaning, you write the code at a high level, instead of detailed commands, the rest will be executed by the Terraform engine. The code is written in what is called HashiCorp Configuration Language. With support from over 200 infrastructure providers including public, private, and SaaS cloud providers, Terraform is quite a popular utility in DevOps circles.

With its declarative nature of code, the final state is visible only at the provider end. If the provider is AWS for example, the final state will be visible on the AWS cloud. If Terraform users need to access the end state, they need to install and configure the applications deployed using various scripts and tools.

Terraform also supports infrastructure orchestration, using execution plans-basically steps to be performed in an orderly fashion and with the use of Resource graphs- a visual representation of the plan. Terraform engines are efficient in spinning up the infrastructure without detailed coding, and a quick description of resources on the stack will do. With Terraform you have to understand that the code is declarative in nature, defining the process using which results can be achieved. The code is a good representation of the infrastructure.

Terraform works well in automating processes that provide resources and can be useful in the process of migration to the cloud.  It offers a command-line interface that can be a quick way to deploy infrastructure as a code. Apart from deployment it can also perform versioning and altering infrastructure making it ideal for cloud management. With a large support base, Terraform offers flexible configurations that may include a variety of service providers alongside in-house solutions.  

Terraform can be a great cloud management solution with support for Multicloud, as it supports a variety of cloud providers. While it is declarative, allowing you to manage high-level instances like SaaS and DNS, it still does have the ability to manage low-level instances like storage and networking hardware. The multi-threaded nature of Terraform allows for parallel computing power that can be used to create a set of resources simultaneously.

Here is a quick and easy summary of the features of Terraform

  • Terraform is a declarative Infrastructure as a coding platform, making the initial deployment quick and easy.
  • Modular code encourages collaboration, reusability, and consistency. Modular code can be reused in various other deployment plans and can easily be tweaked for specificity.
  • A convenient tool to display the resulting model in a graphical form is available with Terraform.
  • One of the few tools that can be used to build infrastructure from scratch, be it public, private, or multi-cloud configurations. 

2) Understanding Ansible

Ansible is an open-source configuration management tool with software provisioning and application-deployment capabilities using Infrastructure as a Code. It features its own declarative language to describe system configuration. One key thing about Ansible is, it is agentless making it easy to manage large deployments across enterprises, using SSH or Windows PowerShell to perform its tasks. Ansible is not purely declarative, it is a hybrid of procedural and declarative paradigms.

Ansible allows you to perform ad-hoc commands, allowing procedural-style configuration, while you can perform high-level declarative-style configurations. Ansible is typically used to install/deploy and manage software on already existing server instances. Deploying and managing installation packages, initialization of services, running scripts or config files on the server instances, are some of the tasks of configuration management tools like Ansible. Although Ansible uses IaaC, it does so for configuration management on already deployed servers.

Ansible is a perfect tool for traditional configuration management, while it cannot be used for orchestration services in a large enterprise with interconnected applications.

A quick summary of the features of Ansible is listed below.

  • Ansible is primarily used for configuration management based on the procedural paradigm.
  • Ansible uses IaaC for system configuration across the infrastructure.
  • Allows you to quickly and easily deploy multi-tier apps while being agentless.
  • Ansible allows your code to be re-entrant meaning, the code can be interrupted and re-entered without any conflicts with other invocations.

3) Let’s now dive into the differences between Terraform vs Ansible.

TerraformAnsible
Terraform uses declarative IaaCAnsible uses IaaC for procedural execution
Terraform is focussed on infrastructure provisioningAnsible is focussed on configuration management within the infrastructure
Terraform is well suited for orchestrating cloud services and setup cloud infrastructure from scratchAnsible is well suited for configuring servers with the right software and updates on already configured cloud
Terraform can be used to deploy computing, storage, load balances and VPCs Ansible can be used to deploy apps on top of the cloud
Terraform does not by default support provisioning of bare-metal serversAnsible is natively capable of provisioning bare-metal servers

Terraform Vs Ansible for Provisioning

Both Ansible and Terraform allow provisioning of infrastructure using IaaC.

Terraform is a pure provisioning tool, and in no way supports configuration management. So, it does the best job at the provisioning of your infrastructure leaving the configuration of software to other tools. Actions like granting access to a bunch of users on the servers after the server is provisioned are out of scope for Terraform. Ansible, on the other hand, is not only a great configuration management tool that can set up the software on already provisioned infrastructure but Terraform can perform the task of provisioning your infrastructure including provisioning of bare metal servers.

Conclusion

While Ansible seems to be able to do both provisioning and configuration management well enough. Terraform has its core strengths in provisioning infrastructure across multiple clouds with support for 200 providers. A combination of Terraform for orchestration services and Ansible for configuration management of the infrastructure seems to be a good model to go by.

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