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Docker & Kubernetes1 min read

Override Helm values at install time

Pass custom files with -f or --values, single keys with --set, and know precedence: defaults, then files, then --set.

Docker & Kubernetes1 min read

Helm upgrade and rollback workflow

Helm upgrade creates a new revision; helm history lists revisions; helm rollback reverts to a prior one; --atomic auto-rolls-back on failure.

Docker & Kubernetes1 min read

How GitOps controllers detect drift and sync

The controller renders desired manifests from Git, diffs them against live cluster objects, marks OutOfSync, then a sync applies the diff to converge.

Docker & Kubernetes1 min read

Managing secrets in a GitOps workflow

Never commit plaintext; encrypt with Sealed Secrets or SOPS, or reference an external store via External Secrets Operator.

Docker & Kubernetes1 min read

Argo CD App of Apps pattern

A parent Application whose manifests are themselves Application resources, so syncing one app declaratively manages many.

Docker & Kubernetes1 min read

GitOps repo layout for environment promotion

Shared base plus per-env overlays via Kustomize or value files, promotion by PR moving a pinned version forward, separating app source from config repos.

Docker & Kubernetes1 min read

Helm migration hooks under GitOps

Use a pre-upgrade hook Job with weights and delete policy; the challenge is GitOps tools render statically and reconcile, conflicting with Helm's imperative hook lifecycle.

Docker & Kubernetes1 min read

What is a Custom Resource Definition?

A CRD registers a new resource kind so the API server stores and serves it like built-ins; it lets you model domain concepts declaratively.

Docker & Kubernetes1 min read

Core components of a Kubernetes Operator

A CRD defines the type, a controller watches instances via the API server and runs a reconcile loop, encoding operational knowledge to drive real state.

Docker & Kubernetes1 min read

Creating an instance of a custom resource

Write a manifest with apiVersion (group/version), kind, metadata.name, and a spec matching the CRD schema, then kubectl apply -f it.

Docker & Kubernetes1 min read

The reconciliation loop in an Operator

Reconcile compares desired spec to observed state and converges them, idempotently; triggered by resource changes, watched dependents, and periodic resync.

Docker & Kubernetes1 min read

Finalizers for clean external cleanup

A finalizer is a key blocking deletion; deletion sets deletionTimestamp, the operator does cleanup then removes the finalizer so the object is purged.

Docker & Kubernetes1 min read

Adding a required field to a live CRD

Don't make it required immediately; add it optional with a default, introduce a new version with conversion, migrate existing objects, then tighten.

Docker & Kubernetes1 min read

When to build an Operator vs a Helm chart

Charts handle install-time templating; operators add continuous day-two logic like failover, backups, and scaling for stateful apps.

Docker & Kubernetes2 min read

Keeping operator .status accurate under failures

Status can lag or go stale during partitions and crashes; make reconcile idempotent, observe true state each loop, use conditions and observedGeneration, handle conflicts.

Docker & Kubernetes1 min read

Mutating vs Validating webhooks with an Operator

Mutating runs first to inject defaults or sidecars, validating runs after to reject bad specs, both keyed to your CRD.

Docker & Kubernetes1 min read

Preventing split-brain in HA Operators

Run active-passive replicas, only the leader reconciles, election uses a Lease object renewed under a TTL.

Docker & Kubernetes1 min read

What a service mesh solves

It adds traffic management, security via mTLS, and observability at the network layer through sidecars, beyond what plain Kubernetes offers.

Docker & Kubernetes1 min read

The sidecar proxy pattern in a mesh

A proxy container shares the pod, all in/out traffic is redirected through it, so policy and telemetry apply without code changes.

Docker & Kubernetes1 min read

Canary release with Istio traffic splitting

DestinationRule defines subsets by label, VirtualService routes weighted 90/10 to those subsets, then shift weights as the canary proves healthy.