Site reliability engineering (SRE) is a set of principles and practices that applies aspects of software engineering to IT infrastructure and operations.^[1] SRE claims to create highly reliable and scalable software systems. Although they are closely related, SRE is slightly different from DevOps.^[2][3][4]

History

The field of site reliability engineering originated at Google with Ben Treynor Sloss,^[5][6] who founded a site reliability team after joining the company in 2003.^[7] In 2016, Google employed more than 1,000 site reliability engineers.^[8] After originating at Google in 2003, the concept spread into the broader software development industry, and other companies subsequently began to employ site reliability engineers.^[9] The position is more common at larger web companies, as small companies often do not operate at a scale that would require dedicated SREs.^[9] Organizations that have adopted the concept include Airbnb, Dropbox, IBM,^[10] LinkedIn, Netflix,^[8] and Wikimedia.^[11] According to a 2021 report by the DevOps Institute, 22% of organizations in a survey of 2,000 respondents had adopted the SRE model.^[12][13]

Definition

Site reliability engineering, as a job role, may be performed by individual contributors or organized in teams, responsible for a combination of the following within a broader engineering organization: System availability, latency, performance, efficiency, change management, monitoring, emergency response, and capacity planning.^[14] Site reliability engineers often have backgrounds in software engineering, system engineering, or system administration.^[15] Focuses of SRE include automation, system design, and improvements to system resilience.^[15]

Site reliability engineering, as a set of principles and practices, can be performed by anyone. Though everyone should contribute to good practices, as occurs in security engineering, a company may eventually hire specialists and engineers for the job.

Site reliability engineering has also been described as a specific implementation of DevOps, although they differ slightly. SRE focuses specifically on building reliable systems, whereas DevOps focuses more broadly.^[2][3][4] Although they have different focuses, some companies have rebranded their operations teams to SRE teams with little meaningful change.^[9]

Principles and practices

There have been multiple attempts to define a canonical list of site reliability engineering principles, but while consensus is lacking, the following characteristics are usually included in most definitions:^[1][16]

• Automation or elimination of anything repetitive in a cost-effective way.
• Avoidance to pursue much more reliability than what's strictly necessary. Defining what's necessary is a practice by itself (see list of practices below).
• Systems designed with a bias toward the reduction of risks to availability, latency, and efficiency.
• Observability—as in, the ability to ask arbitrary questions about a system without having to know ahead of time what to ask.^[17]

The site reliability engineering practices also vary widely, but the list below is relatively commonly seen as at least partially implemented:

• Toil management as the implementation of the first principle outlined above.
• Defining and measuring reliability goals—SLIs, SLOs, and error budgets.
• Non-Abstract Large Scale Systems Design (NALSD) with a focus on reliability.
• Designing for and implementing observability.
• Defining, testing, and running an incident management process.
• Capacity planning.
• Change and release management, including CI/CD.
• Chaos engineering.

Implementations

Site reliability engineering teams engage with the other teams within their companies and the SRE principles and practices in various forms. Here is a high-level overview of common SRE team implementations:^[18]

Industry

The USENIX organization has held an annual SREcon conference since 2014 for site reliability engineers in the industry and also holds regional conferences with similar themes.^[19]

See also

References

Further reading

• Limoncelli, Tom; Chalup, Strata R.; Hogan, Christina J. (September 2014). The Practice of Cloud System Administration: DevOps and SRE Practices for Web Services. Vol. 2. Upper Saddle River, NJ: Addison-Wesley. ISBN 978-0133478549. OCLC 891786231.
• Beyer, Betsy; Jones, Chris; Petoff, Jennifer; Murphy, Niall Richard, eds. (2016). Site Reliability Engineering: How Google Runs Production Systems. O'Reilly. ISBN 978-1491929124.
• Blank-Edelman, David N., ed. (2018). Seeking SRE: Conversations About Running Production Systems at Scale (1 ed.). Sebastopol, CA: O'Reilly. ISBN 978-1491978863. OCLC 1052565720.
• Beyer, Betsy; Murphy, Niall; Kawahara, Kent; Rensin, David; Thorne, Stephen (2018). The Site Reliability Workbook: Practical Ways to Implement SRE. O'Reilly. ISBN 978-1492029502.
• Welch, Nat (2018). Real-World SRE: The Survival Guide for Responding to a System Outage and Maximizing Uptime. Packt. ISBN 978-1788628884.
• Adkins, Heather; Beyer, Betsy; Blankinship, Paul; Lewandowski, Piotr; Oprea, Ana; Stubblefield, Adam (2020). Building Secure and Reliable Systems: Best Practices for Designing, Implementing, and Maintaining Systems. O'Reilly. ISBN 978-1-4920-8312-2. OCLC 1129470292.
• Rosenthal, Jones, Casey, Nora (2020). Chaos Engineering: System Resiliency in Practice. O'Reilly. ISBN 978-1492043867.{{cite book}}: CS1 maint: multiple names: authors list (link)

External links

• Awesome Site Reliability Engineering resources list
• How they SRE resources list
• SRE Weekly weekly newsletter devoted to SRE
• SRE at Google landing page for learning more about SRE in Google
• Komodor K8s Reliability learning center with resources for SREs working with Kubernetes