What is immutable infrastructure?

What is immutable infrastructure?

• A. Replace servers rather than modifying them; reduces drift, simplifies rollback, and improves reproducibility.
• B. Patch the live server in place for quick fixes.
• C. Maintain two versions of software on the same server.
• D. Use manual configuration management to apply changes.

Answer: (A)

Immutable infrastructure means you don’t modify running servers. Instead, you build a new machine image with the desired changes and deploy that fresh instance, then retire the old one. This approach eliminates drift because every server is created from the same, versioned image, ensuring consistent configurations across environments. Updates become predictable and reproducible, since the exact image used can be stored in a registry and redeployed anywhere, making rollbacks straightforward by simply returning to a previous image. Patching a live server in place breaks that model, creating subtle differences over time and increasing the risk of partial updates or misconfigurations. Maintaining two versions on the same server goes against the idea of replacing rather than mixing states. Manual configuration management can help, but immutability emphasizes using replaceable images and automated deployment pipelines rather than ad-hoc in-place changes.

Immutable infrastructure means you don’t modify running servers. Instead, you build a new machine image with the desired changes and deploy that fresh instance, then retire the old one. This approach eliminates drift because every server is created from the same, versioned image, ensuring consistent configurations across environments. Updates become predictable and reproducible, since the exact image used can be stored in a registry and redeployed anywhere, making rollbacks straightforward by simply returning to a previous image.

Patching a live server in place breaks that model, creating subtle differences over time and increasing the risk of partial updates or misconfigurations. Maintaining two versions on the same server goes against the idea of replacing rather than mixing states. Manual configuration management can help, but immutability emphasizes using replaceable images and automated deployment pipelines rather than ad-hoc in-place changes.