Immutable infrastructure is an approach to IT infrastructure management where servers, once deployed, are never modified directly. Instead, any changes require building a new server instance with the desired changes and replacing the old one.
Analogy: Imagine immutable infrastructure as using disposable contact lenses; once used, you discard them and use a fresh pair, ensuring cleanliness and consistency.
Why It Matters: Immutability improves reliability, reduces configuration drift, and simplifies deployments and rollbacks.