SRE Demystified - 01 - SLO SLI and SLA
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The document discusses the concepts of Service Level Indicators (SLIs), Service Level Objectives (SLOs), and Service Level Agreements (SLAs) in the context of Site Reliability Engineering (SRE). It emphasizes the importance of these metrics in ensuring system performance and reliability for tech companies, providing definitions and examples for each term. Overall, it aims to align vendor and client expectations regarding system availability, performance, and accountability.
SRE Demystified - 01 - SLO SLI and SLA
- 1. Introduction to SRE SLO, SLA and SLI ganesh@ganeshniyer.com ganesh.vigneswara@gmail.com, http://ganeshniyer.com Dr Ganesh Neelakanta Iyer
- 2. Site Reliability Engineering Wikipedia • Discipline that incorporates aspects of software engineering and applies them to infrastructure and operations problems. The main goals are to create scalable and highly reliable software systems Google • SRE is what you get when you treat operations as if it’s a software problem Dr Ganesh Neelakanta Iyer 2
- 3. Dr Ganesh Neelakanta Iyer https://twitter.com/DEVOPSINST/status/1273678804951666688/photo/1
- 4. Never tell me the odds!!! 4https://twitter.com/nobl9inc/status/1272974728584663049/photo/1
- 5. Dr Ganesh Neelakanta Iyer https://twitter.com/sureshgp/status/1273643362617159680/photo/1
- 6. What is common for all tech companies? 6
- 7. Users…
- 8. Whether you’re Google’s search engine, serving a billion active monthly users who interact with your service for free, or Salesforce, with 3.75 million paying subscribers, building a technology product means serving people. https://www.atlassian.com/incident-management/kpis/sla-vs-slo-vs-sli
- 9. Hence, it is important for the companies to understand SLOs, SLIs and SLAs - three initialisms that represent the promises we make to our users, the internal objectives that help us keep those promises, and the trackable measurements that tell us how we’re doing. https://www.atlassian.com/incident-management/kpis/sla-vs-slo-vs-sli
- 10. The goal • Get everybody—vendor and client alike—on the same page about system performance – How often will your systems be available? – How quickly will your team respond if the system goes down? – What kind of promises are you making about speed and functionality? – Users want to know—and so you need SLAs, SLOs, and SLIs Dr Ganesh Neelakanta Iyer 10 https://www.atlassian.com/incident-management/kpis/sla-vs-slo-vs-sli
- 11. Dr Ganesh Neelakanta Iyer 11 https://www.atlassian.com/incident-management/kpis/sla-vs-slo-vs-sli
- 12. So what is the difference? SLI What we’ve chosen to measure progress towards our goal. E.g., “Latency of a request.” SLO Stated objective of the SLI – what we’re trying to accomplish for either ourselves or the customer. E.g., “99.5% of requests will be completed in 5ms.” SLA Contract explicitly stating the consequences of failing to achieve your defined SLOs. E.g., “If 99% of your system requests aren’t completed in 5ms, you get a refund.” Dr Ganesh Neelakanta Iyer 12 https://www.circonus.com/2018/07/a -guide-to-service-level-objectives/
- 13. SLI • SLI are the parameters which indicates the successful transactions, requests served by the service over the predefined intervals of time • These parameters allows to measure much required performance and availability of the service • Measuring these parameters also enables to improve them gradually • Key Examples are: – Availability/Uptime of the service. – Number of successful transactions/requests. – Consistency and durability of the data Dr Ganesh Neelakanta Iyer 13https://www.anshulpatel.in/post/sre_sli_sla_slo/
- 14. SLO • SLO defines the acceptable downtime of the service • For multiple components of the service, there can be different parameters which defines the acceptable downtime • It is common pattern to start with low SLO and gradually increase it • Key Examples are: – Durability of disks should be 99.9%. – Availability of service should be 99.95% – Service should successfully serve 99.999% requests/transactions Dr Ganesh Neelakanta Iyer 14https://www.anshulpatel.in/post/sre_sli_sla_slo/
- 15. SLA • SLA defines the penalty that service provider should pay in an event of service unavailability for pre-defined period of time • Service provider should clearly define the failure factors for which they will be accountable(Domain of responsibility) • Key Examples are: – Partial refund of service subscription fee. – Additional subscription time added for free Dr Ganesh Neelakanta Iyer 15https://www.anshulpatel.in/post/sre_sli_sla_slo/
- 17. Dr Ganesh Neelakanta Iyer ganesh@ganeshniyer.com ganesh.vigneswara@gmail.com 17