Infrastructure as Code (IaC)

What Is Infrastructure as Code?

Infrastructure as Code (IaC) is a concept in IT infrastructure management where systems and devices are managed and provisioned through machine-readable definition files or scripts rather than manual hardware configuration or interactive configuration tools. This allows developers to automate provisioning and manage systems and their configurations. The underlying principle of IaC is to treat infrastructure in the same way as any other piece of software code: it can be written, tested, shared, and versioned, allowing rapid, consistent, and repeatable deployment of environments.


Benefits of IaC

The paradigm shift to Infrastructure as Code (IaC) brings several significant advantages over traditional, manual methods of managing infrastructure. With IaC, operations and development teams gain benefits that boost productivity, strengthen the quality, and reduce risks. These advantages extend from ensuring consistency and speed in deployment, to risk reduction, automatic documentation, and efficient scalability. 

Below are examples of each of these benefits, providing a detailed understanding of the transformative power IaC can bring to an organization's IT infrastructure management.

  • Consistency and repeatability: IaC allows the creation of a consistent environment every time it is deployed, reducing the potential for error when configuring systems manually.
  • Speed and efficiency: IaC makes it possible to quickly set up your complete infrastructure by running a script. This allows teams to launch reliable environments in a fraction of the time required by manual provisioning.
  • Reduced Risk: By managing infrastructure as code, changes can be version controlled and rolled back if a problem is detected, reducing the risk of potential outages.
  • Documentation: The code used in IaC effectively serves as documentation of the system, making it easier for new team members to understand the system architecture.
  • Scalability and distribution: IaC supports the infrastructure requirements of modern distributed systems and microservices, as well as scaling infrastructure up and down as per the application's needs.

Declarative vs. Imperative Approaches to IaC

In the context of IaC, the declarative and imperative models represent two different approaches to defining your infrastructure.

The Declarative IaC approach involves declaring the desired state of the infrastructure. The focus is on what the final result should be. You provide a description of the desired state and the tool figures out how to achieve that state.

In an Imperative IaC approach, you must provide explicit commands to reach the desired state. It's a step-by-step method in which you give the system a set of instructions to achieve the desired end state.


Immutable Infrastructure vs. Mutable Infrastructure

Immutable and mutable infrastructure are two different strategies you can use when implementing IaC.

In an immutable infrastructure, once a component is deployed, it is never modified, merely replaced with another instance when a change is needed. The main advantage of this approach is that it avoids configuration drift and ensures consistency across environments.

In a mutable infrastructure, changes are made to existing components. While this can be simpler for small-scale applications, it increases the risk of configuration drift, where small differences accumulate over time between supposedly identical environments