ArgoCD Patterns: App of Apps, ApplicationSets, Multi-Environment Management, and Source Strategies

ArgoCD Patterns#

Once ArgoCD is running and you have a few applications deployed, you hit a scaling problem: managing dozens or hundreds of Application resources by hand is unsustainable. These patterns solve that.

App of Apps#

The App of Apps pattern uses one ArgoCD Application to manage other Application resources. You create a “root” application that points to a directory containing Application YAML files. When ArgoCD syncs the root app, it creates all the child applications.

Building a Kubernetes Deployment Pipeline: From Code Push to Production

Building a Kubernetes Deployment Pipeline: From Code Push to Production#

A deployment pipeline connects a code commit to a running container in your cluster. This operational sequence walks through building one end-to-end, with decision points at each phase and verification steps to confirm the pipeline works before moving on.

Phase 1 – Source Control and CI#

Step 1: Repository Structure#

Every deployable service needs three things alongside its application code: a Dockerfile, deployment manifests, and a CI pipeline definition.

Devcontainer Sandbox Templates: Zero-Cost Validation Environments for Infrastructure Development

Devcontainer Sandbox Templates#

Devcontainers provide disposable, reproducible development environments that run in a container. You define the tools, extensions, and configuration in a .devcontainer/ directory, and any compatible host – GitHub Codespaces, Gitpod, VS Code with Docker, or the devcontainer CLI – builds and launches the environment from that definition.

For infrastructure validation, devcontainers solve a specific problem: giving every developer and every CI run the exact same set of tools at the exact same versions, without requiring them to install anything on their local machine. A Kubernetes devcontainer includes kind, kubectl, helm, and kustomize at pinned versions. A Terraform devcontainer includes terraform, tflint, checkov, and cloud CLIs. The environment is ready to use the moment it starts.

Kustomize Patterns: Bases, Overlays, and Practical Transformers

Kustomize Patterns#

Kustomize lets you customize Kubernetes manifests without templating. You start with plain YAML (bases) and layer modifications (overlays) on top. It is built into kubectl, so there is no extra tool to install.

Base and Overlay Structure#

The standard layout separates shared manifests from per-environment customizations:

k8s/
  base/
    kustomization.yaml
    deployment.yaml
    service.yaml
    configmap.yaml
  overlays/
    dev/
      kustomization.yaml
      replica-patch.yaml
    staging/
      kustomization.yaml
      ingress.yaml
    production/
      kustomization.yaml
      replica-patch.yaml
      hpa.yaml

The base kustomization.yaml lists the resources:

# base/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
  - deployment.yaml
  - service.yaml
  - configmap.yaml

An overlay references the base and adds modifications:

Setting Up Multi-Environment Infrastructure: Dev, Staging, and Production

Setting Up Multi-Environment Infrastructure: Dev, Staging, and Production#

Running a single environment is straightforward. Running three that drift apart silently is where teams lose weeks debugging “it works in dev.” This operational sequence walks through setting up dev, staging, and production environments that stay consistent where it matters and diverge only where intended.

Phase 1 – Environment Strategy#

Step 1: Define Environments#

Each environment serves a distinct purpose:

  • Dev: Rapid iteration. Developers deploy frequently, break things, and recover quickly. Data is disposable. Resources are minimal.
  • Staging: Production mirror. Same Kubernetes version, same network policies, same resource quotas. External services point to staging endpoints. Used for integration testing and pre-release validation.
  • Production: Real users, real data. Changes go through approval gates. Monitoring is comprehensive and alerting reaches on-call engineers.

Step 2: Isolation Model#

Decision point: Separate clusters per environment versus namespaces in a shared cluster.

Static Validation Patterns: Infrastructure Validation Without a Cluster

Static Validation Patterns#

Static validation catches infrastructure errors before anything is deployed. No cluster needed, no cloud credentials needed, no cost incurred. These tools analyze configuration files – Helm charts, Kubernetes manifests, Terraform modules, Kustomize overlays – and report problems that would cause failures at deploy time.

Static validation does not replace integration testing. It cannot verify that a service starts successfully, that a pod can pull its image, or that a database accepts connections. What it catches are structural errors: malformed YAML, invalid API versions, missing required fields, policy violations, deprecated resources, and misconfigured values. In practice, this covers roughly 40% of infrastructure issues – the ones that are cheapest to find and cheapest to fix.

GitOps for Kubernetes: Patterns, Tools, and Workflow Design

GitOps for Kubernetes#

GitOps is a deployment model where git is the source of truth for your cluster’s desired state. A controller running inside the cluster watches a git repository and continuously reconciles the live state to match what is declared in git. When you want to change something, you commit to git. The controller detects the change and applies it.

This replaces kubectl apply from laptops and CI pipelines with a pull-based model where the cluster pulls its own configuration. The benefits are an audit trail in git history, easy rollback via git revert, and drift detection when someone makes manual changes.