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Advanced Topic 48 of 50 Software Engineering

Site Reliability Engineering

Applying software practice to operations with error budgets.

How it works

Site reliability engineering applies software engineering to operations, a discipline originated at Google. It defines reliability targets with service level indicators and objectives and uses error budgets, the allowed amount of unreliability, to balance feature velocity against stability. Practices include monitoring and alerting on symptoms, automation to eliminate toil, capacity planning, incident response with blameless postmortems, on-call rotations and gradual rollouts.

Step-by-step walkthrough

  1. The team sets a service level objective such as 99.9 percent.
  2. The gap to 100 percent is the error budget.
  3. While budget remains, ship new features quickly.
  4. When it is used up, focus on reliability.
  5. Automation reduces toil.

Where it is used

Operating large online services, setting reliability goals, handling incidents and improving systems after outages use SRE methods.

Common pitfall

Treating SRE as renamed system administration misses the engineering focus. Setting 100 percent availability targets is unrealistic and expensive. Too many noisy alerts cause fatigue, and blame-oriented postmortems hide lessons. Define meaningful SLOs, alert on user-visible impact, reduce toil by automation and learn systematically from incidents.

Where it fits in the course

Site Reliability Engineering is topic 48 of 50 in Software Engineering, rated Advanced. It follows Chaos Engineering. The next topic is Software Estimation.

Practice and explore

How to study this topic

  1. Read the explanation above and restate the definition in your own words.
  2. Open the interactive lesson and answer its mini quiz.
  3. Read the common pitfall, then write a short example that avoids it.
  4. Check your understanding in the Software Engineering quiz, and revisit the topic if you miss a question.

Frequently asked questions

What is Site Reliability Engineering?
Applying software practice to operations with error budgets. It belongs to Software Engineering and is an advanced-level topic.
Where do people use Site Reliability Engineering?
Operating large online services, setting reliability goals, handling incidents and improving systems after outages use SRE methods.
What is the most common mistake with Site Reliability Engineering?
Treating SRE as renamed system administration misses the engineering focus.
What should I learn before this topic?
Start with Chaos Engineering, the topic just before it in Software Engineering.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the Software Engineering quiz.
Is Site Reliability Engineering hard to learn?
It is an Advanced topic. Expect to read the explanation more than once and to connect it with earlier topics. Working through a small example by hand helps most.
How long does it take to learn Site Reliability Engineering?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Site Reliability Engineering?
Chaos Engineering, Software Estimation, Property-Based Testing are closely connected. The full list is in the related topics section of this page.
What should I study after Site Reliability Engineering?
Continue with Software Estimation, the next topic in Software Engineering.

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