DevOps Tools, CI/CD and Automation Guides - Page 18

Multi-tenant operators come in three shapes: one operator serving all tenants (shared, simple, weakest isolation), one operator per tenant (isolated, expensive, strongest isolation), and the hybrid — one operator binary …

A complete guide to running a multi-replica Kubernetes operator with leader election: how the lease-based lock works, the four manager options (`LeaderElection`, `LeaderElectionID`, `LeaderElectionResourceLock`, …

A practical guide to liveness and readiness probes for Kubernetes operators: what `/healthz` and `/readyz` should report, how to register custom checks with `mgr.AddHealthzCheck` and `mgr.AddReadyzCheck`, the difference …

Learn how Kubernetes Operator watches, events, handlers, and predicates decide which changes trigger Reconcile, with Owns vs Watches examples.

Most real operators do not manage one child — they manage five, ten, sometimes dozens of children per CR: a Deployment, a Service, two ConfigMaps, a HorizontalPodAutoscaler, a NetworkPolicy, a ServiceAccount, a …

The status subresource is the API server endpoint controllers use to publish observed state without racing user edits on `.spec`. This guide explains why the split exists, the KEP-1623 Conditions standard (Ready / …

Learn how the Kubernetes reconcile loop works from API watch to informer cache, workqueue, and Reconcile(). Covers level-triggered control, Result return paths, requeue behavior, idempotency, concurrency, and hot loop …

Red Hat's five operator capability levels - Basic Install, Seamless Upgrades, Full Lifecycle, Deep Insights, Auto Pilot - are the maturity scale used by OperatorHub and OLM. This guide explains what each level means, …

Kubernetes Operators are not one shape - six distinct design patterns cover the entire range of production deployments: Singleton, Capability, Lifecycle, Auto-Pilot / Auto-Tune, Sidecar-Injecting, and GitOps-Controlled. …

A complete guide to admission webhooks for Kubernetes operators: the difference between mutating and validating, the webhook lifecycle inside the API server, how kubebuilder scaffolds …

A Kubernetes finalizer is a string on `metadata.finalizers` that tells the API server to keep an object alive (with `deletionTimestamp` set) until your controller has finished cleanup and removed the string. This …

Three tools install Helm charts on a Kubernetes cluster: a Helm-based operator (per-CR Helm install), Flux's HelmRelease (HelmRelease CR + per-source reconciler), and Argo CD's Application (Application CR + sync engine). …

A Kubernetes operator detects drift in four layered ways: watch-based reconciliation, periodic resync with SyncPeriod, three-way spec diffing with client.Patch or Server-Side Apply, and external polling for resources …

In Kubernetes, the desired state is what you declared in `.spec`, the actual state is what currently exists in the cluster, and the controller's job is to continuously reconcile the two. This guide explains why …

A Helm hybrid operator is a Go operator whose Reconcile calls the Helm SDK (v4) directly - the pre-built helm-operator, written by you, with full control. Part 1 of 2 walks the foundation: scaffold with operator-sdk init …

A Helm-based operator wraps a Helm chart as a Kubernetes operator without you writing any Go code. The Operator SDK ships a generic reconciler that watches a CR, maps its `.spec` to Helm values, and runs `helm install` / …

A complete guide to owner references and Kubernetes garbage collection for operators: the contract between an owner and its dependents, the difference between `SetControllerReference` and `SetOwnerReference`, three …

A complete step-by-step guide to installing Operator-SDK on Linux (Ubuntu, RHEL, Fedora, Debian), including the prerequisite toolchain (Go 1.22+, kubectl, container runtime, Helm 4 CLI, kind), the three Operator-SDK …

A Custom Resource Definition (CRD) is the API contract, a Controller is the reconciler that watches and acts on it, and an Operator is the combination of a CRD plus a controller plus domain-specific knowledge about a …

A Kubernetes Operator is a custom controller paired with a Custom Resource Definition (CRD) that automates the day-2 operations of a complex application - install, upgrade, backup, failover, scaling - by continuously …

Learn how to design a scalable parcel management system using APIs, database schema, event-driven architecture, queues, and cloud-native technologies like Kafka and Kubernetes.

Learn how to implement JWT authentication in Golang using Gin and PostgreSQL. This step-by-step guide covers user signup, login, JWT token generation, middleware validation, REST API usage, and common errors for building …

Learn why understanding hardware fundamentals like CPU, memory, storage, and printed circuit boards is essential for developers to build high-performance, scalable, and reliable applications in modern computing …

Learn how to delete a repository in GitHub using both the web interface and command line. This guide explains how to remove GitHub repositories, delete local Git repositories, remove files and folders, and safely clean …

Learn how to use git switch to change branches in Git. This guide explains git switch vs git checkout, switching branches, creating new branches, commands, examples, and fixing common errors.

Learn how to use git stash to save local changes without committing. This guide covers git stash commands, examples, applying and popping stashes, listing stashes, fixing errors like no local changes to save, and …

Learn how to use git tag to create, list, push, delete, and manage tags in Git. This guide covers tagging concepts, version tagging, commands, examples, and best practices for release management.

Learn how to squash commits in Git using rebase and merge. This guide covers combining commits, squashing last N commits, squashing all commits in a branch, before and after push workflows, fixing errors, and recovering …

Learn how to set upstream in Git with practical examples, fix common errors like no upstream branch, and understand origin vs upstream. This guide covers git push --set-upstream, git branch upstream setup, fork …

Learn how to use the git rm command with practical examples. This guide covers removing files and folders, git rm vs rm differences, git rm --cached usage, undoing git rm, and handling real-world scenarios safely without …