What is Site Reliability Engineering, and how does it relate to DevOps?

Summary

SRE is an engineering discipline, originated at Google, that applies software engineering to operations: reliability targets are defined with SLOs, risk is managed with error budgets, toil is automated away, and incidents are learned from. DevOps is a broader culture of shared ownership between development and operations; SRE is one concrete way to implement it.

Longer Answer

Google describes SRE as "what happens when you ask a software engineer to design an operations team". Core practices: SLIs and SLOs agreed with product owners, error budgets that balance reliability and release speed, a cap on operational toil (Google targets under 50% of an SRE's time), blameless postmortems, and engineering work that removes classes of failure.

The SRE workbook puts it as "class SRE implements interface DevOps": both value shared responsibility, automation, measurement and small changes; SRE adds prescriptive mechanisms. Job titles vary a lot between companies, from platform engineering to on-call operations, so ask what the role means locally.

Key Points

• Software engineering applied to operations.
• SLOs, error budgets, toil limits, postmortems.
• SRE is one implementation of DevOps.
• Titles vary between companies.

What interviewers look for

Understanding of the mechanisms (SLOs, error budgets, toil caps), not just 'SRE keeps things up'.