Joshua Resnick - Fotolia
Mutable and immutable infrastructures dictate the way an IT operations team handles server maintenance and adjustment. Mutable systems are changed and updated directly, whereas immutable images are static and any updates must generate a new version of the base image.
Immutable infrastructure is beneficial in cloud and microservices environments due to the sheer number of interdependent parts. Manually address issues on a one-off basis and you can create configuration drift chaos that inevitably spins out of control as new updates go live over time.
The immutable approach means that if there is an issue on only a couple of identical servers, all of the servers get updated, not just those affected. Immutable infrastructure creates uniformity and facilitates version tracking insofar as every new server, VM or other infrastructure setup is documented and maintained. In the event of a failure or other problem, the infrastructure team can roll back configurations to the last known-good version.
Take this quiz to see if you can identify mutable and immutable infrastructure models in the wild.