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10. Site Reliability Engineering (SRE).

SRE Principles.​

Site Reliability Engineering (SRE) is a discipline created by Google that combines software engineering with operations to build highly reliable, scalable, and efficient systems.

SRE brings engineering mindset, automation, and data-driven decisions to operations.

> SRE makes sure systems are fast, reliable, and always available without slowing down development.

1. Reduce toil​

Toil is the repetitive, manual, boring operations work that does not create long-term value.

  • Manual deployments.

  • Manual server setups.

  • Repeated ticket handling.

  • Manually restarting services.

How SRE reduces toil: –

  • Manual work leads to mistakes.

  • Developers waste time doing operational tasks.

  • Toil limits scaling.

> Automate or eliminate as much toil as possible.

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2. Reliability as a feature​

Reliability is not optional it is treated like a core feature of the product.

Why it matters: –

  • Customers expect services to be always available.

  • Unreliable systems harm business reputation.

  • Reliability builds trust.

Ex: –** **A product may delay new features if reliability drops below acceptable level.

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3. Error budgets​

Error budget = the allowed amount of failure within a given period based on SLOs.

Ex: – If SLO = 99.9% uptime, Error Budget = 0.1% allowed downtime.

Why error budgets matter: –

  • Balance between speed and reliability.

  • If error budget is consumed, teams slow down releases.

  • If error budget remains, teams can release faster.

> Error budgets link SRE and developers together.

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4. SLOs / SLIs​

SLO (Service Level Objective): –​

A target performance level for an SLI. Ex: – “Availability should be 99.9%.”

SLI (Service Level Indicator): –​

A metric that measures service performance. Ex: – latency, error rate, availability.

Why they matter: –

  • Help define reliability goals.

  • Provide clear expectations.

  • Remove guesswork and conflict.

  • Guide engineering decisions.

> SLOs help teams know when they can move fast and when they need to stabilize.

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5. Automate everything​

SRE teams automate as many processes as possible deployments, scaling, monitoring, remediation.

Why it matters: –

  • Reduces manual errors.

  • Saves engineer time.

  • Makes systems predictable.

  • Helps with scaling.

  • Enables reliable, repeatable processes.

> Automation is a core SRE principle.

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6. Blameless Postmortems​

After an incident or outage, the team analyses what happened without blaming any individual.

Why it matters: –

  • Encourages honesty.

  • Enables learning from failures.

  • Builds trust.

  • Reduces fear.

  • Prevents repeating mistakes.

> Blameless culture is essential for reliability improvement.

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7. Observability​

Observability is the ability to understand what is happening inside a system using: – Logs, Metrics, Traces, Dashboards.

Why it matters: –

  • Helps diagnose issues quickly.

  • Improves MTTR.

  • Helps identify performance bottlenecks.

  • Supports proactive improvements.

> Observability is the backbone of modern SRE.