What Is… Explainers
Plain definitions of terms that get used loosely.
Short, definitional explainers for the concepts that get thrown around without agreement on what they mean. Each one leads with a straight answer, then links into the deeper material.
8 articles in this series
- 018 min
What Is a Kubernetes Operator? The Custom-Controller Pattern Explained
A Kubernetes operator is a custom controller plus one or more CRDs that extends the Kubernetes API to automate an application's full lifecycle — install, upgrade, backup, failover. It encodes a human operator's runbook as software that continuously reconciles desired state.
Read - 029 min
What Is a Service Mesh? Sidecars, mTLS, and Traffic Control Explained
A service mesh is a dedicated infrastructure layer that manages service-to-service communication through proxies — adding mTLS, traffic control, resilience, and observability without touching application code. Here's how it works and whether you actually need one.
Read - 0310 min
What Is Ansible? Agentless Configuration Management Explained
Ansible connects over SSH, pushes small programs to the machines you name, runs them, and deletes them. No agent, no database, no daemon. Here's the actual execution model, what idempotence really means in practice, and where Ansible stops being the right tool.
Read - 049 min
What Is GitOps? Git as the Source of Truth for Infrastructure
GitOps is an operating model where Git holds the declarative desired state of your systems and an in-cluster agent continuously reconciles the real world to match it. Here's how the reconcile loop works, why it's pull-based, and what it actually solves.
Read - 0510 min
What Is Infrastructure as Code (IaC)? Concepts, Tools, and Trade-offs
Infrastructure as Code means managing and provisioning servers, networks, and cloud services through machine-readable definition files instead of manual clicks. Here's how it works, the declarative-vs-imperative and mutable-vs-immutable distinctions, and the tools that matter.
Read - 0610 min
What Is Kubernetes? Container Orchestration Explained
Kubernetes is an open-source container orchestration platform that runs containerised applications across a cluster of machines. You declare the state you want — how many copies, how much memory, which network route — and Kubernetes continuously works to make reality match, rescheduling and restarting containers as machines fail.
Read - 078 min
What Is Ollama? Running LLMs on Your Own Machine Explained
Ollama is an open-source tool that downloads and runs large language models locally on your own computer. It bundles model weights, quantisation, and a server into a single command, exposing an HTTP API on localhost so applications can use a private LLM with no API key and no data leaving the machine.
Read - 0810 min
What Is Platform Engineering? Internal Developer Platforms Explained
Platform engineering is the discipline of building and running an Internal Developer Platform — a self-service layer of tools, golden paths, and automation, treated as a product — so product teams can ship independently without drowning in infrastructure detail.
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