What are SLO, SLA, and SLI? Simple Explanation with Examples

What are SLO, SLA, and SLI? If you’ve ever dived into SRE (Site Reliability Engineering) or service monitoring, you’ve likely seen three mysterious abbreviations: SLO, SLA, and SLI. They might look similar, but they play different roles in how we measure and guarantee reliability. SLI — Service Level Indicator This is a metric that tells you how your service is doing. Examples: Latency (e.g., “response time of API requests”) Availability (e.g., “percentage of successful requests”) Error rate (e.g., “number of 5xx responses”) 👉 Think of SLI as a thermometer — it measures the state of your system. ...

September 25, 2025 · 2 min · 297 words · John Cena

What is a Percentile in Observability? Simple Explanation with Examples

What is a Percentile in Observability? When we talk about observability, especially metrics like latency, we often hear terms such as p50, p95, or p99. These are percentiles. They give us a way to understand not just the average behavior of a system, but how it performs for the majority (or the unlucky few) of requests. Simple Definition A percentile tells you the value below which a given percentage of measurements fall. ...

September 25, 2025 · 2 min · 301 words · John Cena

What is an SRE (Site Reliability Engineer)?

Site Reliability Engineering (SRE) may sound like a fancy job title, but it’s actually one of the most practical and important roles in modern infrastructure and software teams. What is an SRE? SRE stands for Site Reliability Engineer. In simple terms, an SRE ensures that systems are reliable, scalable, and efficient. The concept was born at Google, where software engineers were tasked with running production systems using software engineering principles. ...

July 25, 2025 · 2 min · 221 words · John Cena

Who is a DevOps Engineer?

Who is a DevOps Engineer? If you’ve spent any time in the world of software development or operations, you’ve probably heard the term DevOps thrown around. But what does it actually mean to be a DevOps engineer? Let’s break it down in simple terms. Dev + Ops = Collaboration At its core, DevOps is a cultural and technical movement that aims to bridge the gap between development (Dev) and operations (Ops). Traditionally, developers wrote code and handed it off to system administrators to deploy and maintain it. This often led to misunderstandings, delays, and finger-pointing when something broke. ...

July 25, 2025 · 2 min · 321 words · John Cena

SRE Golden Signals: simple and practical

Site Reliability Engineering (SRE) is not just about “keeping things up” — it’s about building systems that are reliable and understandable. At the heart of this idea lies a simple but powerful toolset: the four golden signals. Let’s break them down in human terms — no jargon, just practical insights. 🚨 What Are the Golden Signals? Golden signals are the four key metrics that Google’s SRE team recommends tracking for any user-facing service: ...

July 24, 2025 · 2 min · 338 words · DevOps Insights