SRE Demystified - 09 - Simplicity
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SRE aims to balance system stability and agility by pursuing simplicity. The key aspects of simplicity according to SRE are minimizing accidental complexity, reducing software bloat through unnecessary lines of code, designing minimal yet effective APIs, creating modular systems, and implementing single changes in releases to easily measure their impact. The ultimate goal is reliable systems that allow for developer agility.
SRE Demystified - 09 - Simplicity
- 1. SRE Demystified Simplicity ganesh@ganeshniyer.com ganesh.vigneswara@gmail.com, http://ganeshniyer.com Dr Ganesh Neelakanta Iyer
- 3. Simplicity • Software systems are inherently dynamic and unstable • A good summary of the SRE approach to managing systems is: "At the end of the day, our job is to keep agility and stability in balance in the system 3 The price of reliability is the pursuit of the utmost simplicity. C.A.R. Hoare, Turing Award lecture https://landing.google.com/sre/sre-book/chapters/simplicity/
- 4. System Stability Versus Agility • For the majority of production software systems, we want a balanced mix of stability and agility • SREs work to create procedures, practices, and tools that render software more reliable • At the same time, SREs ensure that this work has as little impact on developer agility as possible • Building reliability into development allows developers to focus their attention on what we really do care about—the functionality and performance of their software and systems 4 https://landing.google.com/sre/sre-book/chapters/simplicity/
- 5. Accidental Complexity • Essential complexity is the complexity inherent in a given situation that cannot be removed from a problem definition, whereas accidental complexity is more fluid and can be resolved with engineering effort • With an eye towards minimizing accidental complexity, SRE teams should: • Push back when accidental complexity is introduced into the systems for which they are responsible • Constantly strive to eliminate complexity in systems they onboard and for which they assume operational responsibility 5 https://landing.google.com/sre/sre-book/chapters/simplicity/
- 6. The "Negative Lines of Code" Metric • The term "software bloat" was coined to describe the tendency of software to become slower and bigger over time as a result of a constant stream of additional features • While bloated software seems intuitively undesirable, its negative aspects become even more clear when considered from the SRE perspective: every line of code changed or added to a project creates the potential for introducing new defects and bugs 6 https://landing.google.com/sre/sre-book/chapters/simplicity/
- 7. Minimal APIs • Writing clear, minimal APIs is an essential aspect of managing simplicity in a software system • The fewer methods and arguments we provide to consumers of the API, the easier that API will be to understand, and the more effort we can devote to making those methods as good as they can possibly be • In software, less is more! A small, simple API is usually also a hallmark of a well-understood problem 7 https://landing.google.com/sre/sre-book/chapters/simplicity/
- 8. Modularity • The ability to make changes to parts of the system in isolation is essential to creating a supportable system • Versioning APIs allows developers to continue to use the version that their system depends upon while they upgrade to a newer version in a safe and considered way • The concept of modularity also applies to data formats. One of the central strengths and design goals of Google’s protocol buffers was to create a wire format that was backward and forward compatible. 8 https://landing.google.com/sre/sre-book/chapters/simplicity/
- 9. Release simplicity • It is much easier to measure and understand the impact of a single change rather than a batch of changes released simultaneously • If we release 100 unrelated changes to a system at the same time and performance gets worse, understanding which changes impacted performance, and how they did so, will take considerable effort or additional instrumentation 9 https://landing.google.com/sre/sre-book/chapters/simplicity/
- 10. References 10
- 11. Dr Ganesh Neelakanta Iyer ganesh@ganeshniyer.com ganesh.vigneswara@gmail.com