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Infrastructure as Code: Mutable Vs Immutable

July 23, 2020

As Infrastructure as Code (Iac), Internet of Things (IoT), big data and cloud computing become the new standard in IT and business best practices, infrastructures are becoming immutable. This marks a major shift from traditional modes of operation and is worth taking a closer look at.

Before we dive into specifics and understand the benefits of immutable IaC systems, let’s take a moment to review and define key terms. If you aren’t familiar with the term mutable, it refers to something that is prone to change and is easily mutated. Immutable, on the other hand, describes something that is not capable of change.

Mutable IaC

When it comes to IaC, mutable refers to an infrastructure that needs to be constantly updated and changed in order to continue to meet the changing needs of the business. This means that IT professionals have to individually address each server and switch, which can translate into long hours spent identifying problems and coming up with solutions instead of taking the time to rebuild the system in a way that removes any quirks. Since each component is different and requires a unique approach that can often only be performed by one person, the servers are sometimes referred to as snowflakes.

As you may imagine, this approach can be problematic. Mutable IaC creates a situation where only certain IT professionals can address problems. If something goes wrong and that individual isn’t available, there is no way to quickly respond to glitches in the system. While this model created an environment where IT staff felt more needed and valuable, it wasn’t necessarily in the best interest of overall operations.

The other problem with the mutable infrastructure is that over time, businesses may face configuration drifts. For example, let’s say that you are dealing with 10 app services and over time, you are adding various configuration changes to those app services. It is very possible that each of those app services accumulate various executables stacked on each other to provide the required function. This is something to consider when thinking about how a mutable IaC may affect your project in the long run.

Immutable IaC

Immutable IaC represents the future by requiring that each component is built according to exact specifications. There is no room for small deviations that have to be individually addressed. Once a change is required, the infrastructure is provisioned according to the new requirements and the old IaC is taken out of commission.

This same approach is being used with other forms of technology. Consider phones that are equipped with batteries that can’t be replaced. Instead of upgrading the device, you have to purchase an entirely new phone. While this may seem like a waste, it actually provides a level of consistency that makes it easier to provide support. The same is true when it comes to immutable IaC.

Immutable IaC is largely made possible by the advent of virtualization. This tool uses cloud computing to virtualize both hardware and software so that businesses don’t have to worry about provisioning and removing obsolete hardware every time a change is needed. Instead, businesses can document all the steps and requirements involved in creating resources, create code scripts that can assemble the components as outlined in the documentation and automate the entire process. IT teams can also track and record changes for an immutable IaC that can be easily understood and updated by the entire team.

Immutable IaC and DevOps

The traditional mutable approach to infrastructure causes delays in the DevOps pipeline. Dependencies can make application deployments difficult and human innovation is actually slowed down by technology. Immutable IaC creates consistent environments that allow for automated testing and deployment that accelerates the DevOps process and eliminates delays and clogs in the pipeline.

With immutable IaC, teams don’t have to worry about manually validating changes. Everything can be handled through a continuous delivery pipeline that automates all the deployment and testing requirements. New applications can go online faster and all the usual risks associated with change can be eliminated.

Just because mutable infrastructures have been the standard doesn’t mean that they are the best solution. IT teams may be reluctant to let go of their manual update responsibilities, but automating tasks ultimately create more time and space for them to work on true innovations that can push the company forward.

If you have more questions about the benefits of immutable IaC and how you can implement this approach at your business, contact the experts at prancer. We specialize in cloud validation frameworks that support continuous compliance. We can provide you with advice, support and tools you need to take full advantage of cloud computing and IaC.