What Is Infrastructure as Code?

Since repeatable, reusable code enables advanced automation, engineering teams can set up infrastructure simply by running a script. This can be done at all stages of the application development process—including design, testing, and production—resulting in more efficiency and better alignment between application and infrastructure. Ultimately, this results in faster development timelines.

Immutable infrastructure gives application development teams more confidence to test and run their applications, since the new versions of the infrastructure are always deployed as brand-new, purposely built deployments.

In addition, reusable code can help reduce human error. Since all team members are working with the same file, which provides a single source of truth, versioning errors and configuration drift are all but eliminated.

Finally, this practice also eliminates another source of errors: the inconsistencies in documentation that typically accompany deployments. With IaC, the configuration file serves as its own documentation, eliminating the need for an external version.

With IaC, the infrastructure provisioning expertise resides in code that everyone can share, as opposed to silos of knowledge across IT and operations teams.

Configuration management tools are used to install and manage deployments on existing server instances. These tools assign roles to instances without the user needing to specify exact instructions manually.

Orchestration tools allow IT teams to provision server instances and leave configuration to other tools. Orchestration tools are better suited to complex deployments across multiple environments and clusters.

IaC tools use one of two programming logic types: declarative or imperative.

With the declarative approach, the end state of the infrastructure is specified, and the tool assembles it automatically, aiming to always maintain the desired state. This is the most common method used by enterprises.

With the imperative approach, the tool helps prepare automation scripts that are then used to assemble infrastructure one step at a time. While this approach requires more work, it has the advantage of requiring less expertise, and can reuse existing automation scripts from previous deployments.

Using IaC, IT teams can establish provision either mutable or immutable infrastructure.

Mutable infrastructure can be modified or updated after deployment. While this approach allows for flexibility, it also undermines the main benefit of IaC, specifically, the consistency its versioning protections provide, ensuring the application will always run as designed.

Immutable infrastructure is replaced in full when changes are needed, ensuring that a consistent process is used for every deployment. With the flexibility and quick availability of cloud infrastructure, and the speed and reliability of IaC development, repeatedly replacing immutable infrastructure is no longer impractical.

Most configuration processes are documented somewhere within an organization. Gather these instructions and place them in version or source control systems where code can be managed and tracked. This way, whenever team members change code, the changes are documented and in one place.

Look for simple, well-defined tasks that can be automated using basic steps, such as server policies and profiles, or Kubernetes cluster deployments.

There are many IaC tools available, but the IT industry has converged around top tool vendors such as HashiCorp with Terraform and Red Hat with Ansible.