immutable vs mutable infrastructure

A side-by-side comparison of immutable vs. mutable infrastructure

In the constantly shifting landscape for business technology, the only constant is change. 43% of senior executives say they’re increasing IT budgets in order to keep up with the rapid pace of technological evolution. One of those evolution’s is immutable vs. mutable infrastructure.

The question of immutable vs. mutable infrastructure is a fundamental one for your enterprise server management and maintenance. This article will discuss the pros and cons of both choices so you can make the most informed decisions when choosing the best infrastructure for your business.

What is mutable infrastructure?

The word “mutable” means “liable to change,” which makes the term “mutable infrastructure” a very apt one. Mutable infrastructure is IT server infrastructure that is capable of being modified and updated in-place on a regular basis.

Traditionally, server architectures have been mutable due to the greater short-term flexibility that the mutable approach provides. However, mutable infrastructure comes at the cost of predictability and consistency between different server deployments, as is possible with immutable infrastructure.

The advantages of mutable infrastructure include:

  • The infrastructure can more precisely fit the needs of the applications that are running on the server.
  • Updates are usually faster and can be adapted to each individual server.
  • Rather than needing to create a new server from scratch (which can seem like a scary prospect), IT staff get to know each server on a “personal” level, which can sometimes help fix problems more quickly.

The drawbacks of mutable infrastructure include:

  • Technical issues are difficult to diagnose or reproduce because each server has a unique configuration, a phenomenon often known as “configuration drift.”
  • Changes to the server are not necessarily documented, making version tracking more difficult.
  • Provisioning servers is usually a long process due to the need for manual configuration.

What is immutable infrastructure?

As you might have guessed, the word “immutable” is the antonym of “mutable,” meaning “unchanging or unable to change.” Immutable infrastructure is IT server infrastructure that, once deployed, cannot be modified. It’s often associated with the software engineering practices DevOps and continuous delivery.

In the event that changes or updates need to be made, an entirely new instance with the proper modifications is deployed onto the server. New environments can be spawned in the cloud in a matter of minutes. This makes immutable infrastructure a much more feasible option for the 96% of businesses that use the cloud.

The advantages of immutable infrastructure include:

  • Version tracking and rollbacks are much easier. The IT department can keep tabs on each new server or virtual machine as it is deployed.
  • Tests are easier to run thanks to the consistency in configurations between different servers.
  • Configuration drift is not possible. If a server is up and running, the IT staff know the exact state of that server and can avoid any unexpected surprises.

The drawbacks of immutable infrastructure include:

  • The infrastructure is completely unable to be modified in-place. In the event of a zero-day vulnerability, for example, all servers with the same configuration must receive a security update.
  • The improved agility and dynamism of immutable infrastructure can sometimes be misaligned with traditional IT security practices.

Related: The Benefits of Immutable Infrastructure

Need some advice about whether mutable or immutable infrastructure is right for you? Reach out to an experienced IT managed services provider.