Kustomize Overlay Freelance IT Career

Kustomize Overlay

Kustomize Overlay Kubernetes Configuration Template-free Base Overlay Environment GitOps ArgoCD Flux kubectl Freelance IT Career Multi-client Portfolio

Kustomize Structure

# === Kustomize Base + Overlay ===

# Directory Structure
# my-app/
# ├── base/
# │   ├── kustomization.yaml
# │   ├── deployment.yaml
# │   ├── service.yaml
# │   └── configmap.yaml
# ├── overlays/
# │   ├── dev/
# │   │   ├── kustomization.yaml
# │   │   ├── replica-patch.yaml
# │   │   └── env-patch.yaml
# │   ├── staging/
# │   │   ├── kustomization.yaml
# │   │   └── replica-patch.yaml
# │   └── production/
# │       ├── kustomization.yaml
# │       ├── replica-patch.yaml
# │       ├── resource-patch.yaml
# │       └── hpa.yaml

# base/kustomization.yaml
# apiVersion: kustomize.config.k8s.io/v1beta1
# kind: Kustomization
# resources:
#   - deployment.yaml
#   - service.yaml
#   - configmap.yaml
# commonLabels:
#   app: my-app
#   managed-by: kustomize

# base/deployment.yaml
# apiVersion: apps/v1
# kind: Deployment
# metadata:
#   name: my-app
# spec:
#   replicas: 1
#   selector:
#     matchLabels:
#       app: my-app
#   template:
#     metadata:
#       labels:
#         app: my-app
#     spec:
#       containers:
#         - name: app
#           image: my-app:latest
#           ports:
#             - containerPort: 8080
#           resources:
#             requests:
#               cpu: 100m
#               memory: 128Mi
#             limits:
#               cpu: 500m
#               memory: 512Mi

# overlays/production/kustomization.yaml
# apiVersion: kustomize.config.k8s.io/v1beta1
# kind: Kustomization
# resources:
#   - ../../base
#   - hpa.yaml
# namespace: production
# namePrefix: prod-
# images:
#   - name: my-app
#     newTag: v1.5.0
# patches:
#   - path: replica-patch.yaml
#   - path: resource-patch.yaml
# configMapGenerator:
#   - name: app-config
#     literals:
#       - ENV=production
#       - LOG_LEVEL=warn
#       - DB_HOST=prod-db.example.com

# Commands
# kubectl apply -k overlays/dev/        # Deploy to dev
# kubectl apply -k overlays/staging/    # Deploy to staging
# kubectl apply -k overlays/production/ # Deploy to production
# kubectl kustomize overlays/production/ # Preview output

from dataclasses import dataclass

@dataclass
class KustomizeFeature:
    feature: str
    syntax: str
    use_case: str
    example: str

features = [
    KustomizeFeature("namePrefix", "namePrefix: prod-", "แยก Resource ตาม Env", "prod-my-app"),
    KustomizeFeature("namespace", "namespace: production", "กำหนด Namespace", "Deploy to NS"),
    KustomizeFeature("images", "images: [{name, newTag}]", "เปลี่ยน Image Tag", "v1.5.0"),
    KustomizeFeature("patches", "patches: [path: patch.yaml]", "แก้ไข Resource", "Replicas Resources"),
    KustomizeFeature("configMapGenerator", "configMapGenerator:", "สร้าง ConfigMap", "ENV Variables"),
    KustomizeFeature("secretGenerator", "secretGenerator:", "สร้าง Secret", "DB Password"),
    KustomizeFeature("commonLabels", "commonLabels:", "ใส่ Label ทุก Resource", "app: my-app"),
]

print("=== Kustomize Features ===")
for f in features:
    print(f"  [{f.feature}] {f.syntax}")
    print(f"    Use: {f.use_case} | Example: {f.example}")

Multi-client Setup

# === Freelance Multi-client Kustomize ===

# Directory Structure for Multiple Clients
# platform/
# ├── base/
# │   ├── kustomization.yaml
# │   ├── deployment.yaml
# │   ├── service.yaml
# │   ├── ingress.yaml
# │   └── configmap.yaml
# ├── clients/
# │   ├── client-a/
# │   │   ├── kustomization.yaml  # namespace: client-a
# │   │   ├── domain-patch.yaml   # client-a.example.com
# │   │   └── config-patch.yaml   # Client-specific config
# │   ├── client-b/
# │   │   ├── kustomization.yaml
# │   │   ├── domain-patch.yaml   # client-b.example.com
# │   │   └── resource-patch.yaml # Different resource needs
# │   └── client-c/
# │       ├── kustomization.yaml
# │       └── domain-patch.yaml

# Client Overlay Example
# clients/client-a/kustomization.yaml
# apiVersion: kustomize.config.k8s.io/v1beta1
# kind: Kustomization
# resources:
#   - ../../base
# namespace: client-a
# namePrefix: ca-
# images:
#   - name: my-app
#     newTag: v2.1.0
# patches:
#   - path: domain-patch.yaml
# configMapGenerator:
#   - name: app-config
#     behavior: merge
#     literals:
#       - CLIENT_NAME=ClientA
#       - DOMAIN=client-a.example.com
#       - PLAN=enterprise

@dataclass
class ClientSetup:
    client: str
    namespace: str
    domain: str
    plan: str
    replicas: int
    monthly_fee: str

clients = [
    ClientSetup("Client A (E-commerce)", "client-a", "shop-a.example.com", "Enterprise", 3, "$2,000"),
    ClientSetup("Client B (SaaS)", "client-b", "app-b.example.com", "Business", 2, "$1,500"),
    ClientSetup("Client C (Startup)", "client-c", "client-c.example.com", "Starter", 1, "$800"),
    ClientSetup("Client D (Agency)", "client-d", "client-d.example.com", "Business", 2, "$1,500"),
]

print("\n=== Multi-client Deployments ===")
total_revenue = 0
for c in clients:
    fee = int(c.monthly_fee.replace("$", "").replace(",", ""))
    total_revenue += fee
    print(f"  [{c.client}] NS: {c.namespace}")
    print(f"    Domain: {c.domain} | Plan: {c.plan}")
    print(f"    Replicas: {c.replicas} | Fee: {c.monthly_fee}/mo")

print(f"\n  Total Monthly Revenue: ")
print(f"  Infrastructure Cost: ~$500/mo")
print(f"  Profit Margin: {((total_revenue - 500) / total_revenue) * 100:.0f}%")

GitOps Workflow

# === GitOps with Kustomize + ArgoCD ===

# ArgoCD Application
# apiVersion: argoproj.io/v1alpha1
# kind: Application
# metadata:
#   name: client-a-production
#   namespace: argocd
# spec:
#   project: default
#   source:
#     repoURL: https://github.com/freelancer/platform
#     targetRevision: main
#     path: clients/client-a
#   destination:
#     server: https://kubernetes.default.svc
#     namespace: client-a
#   syncPolicy:
#     automated:
#       prune: true
#       selfHeal: true
#     syncOptions:
#       - CreateNamespace=true

# CI/CD — GitHub Actions
# name: Deploy
# on:
#   push:
#     branches: [main]
# jobs:
#   deploy:
#     runs-on: ubuntu-latest
#     steps:
#       - uses: actions/checkout@v4
#       - name: Validate Kustomize
#         run: |
#           for dir in clients/*/; do
#             echo "Validating $dir..."
#             kubectl kustomize "$dir" | kubeval --strict
#           done
#       - name: Update image tag
#         run: |
#           cd clients/client-a
#           kustomize edit set image my-app=my-app:}
#       - name: Commit and push
#         run: |
#           git add .
#           git commit -m "Update image to }"
#           git push

freelance_workflow = {
    "New Client Onboarding": "Copy template overlay ปรับ Config 30 นาที",
    "Deploy Update": "Git push → ArgoCD auto-sync 2 นาที",
    "Rollback": "Git revert → ArgoCD auto-sync 1 นาที",
    "Scale Up": "Edit replica-patch.yaml → Git push",
    "Add Feature": "Update base → All clients get update",
    "Client-specific": "Edit client overlay → Only that client",
    "Monthly Report": "ArgoCD Dashboard + kubectl top",
}

print("Freelance GitOps Workflow:")
for step, desc in freelance_workflow.items():
    print(f"  [{step}]: {desc}")

เคล็ดลับ

• Base: สร้าง Base ที่ดี ใช้ซ้ำกับทุก Client
• Overlay: แต่ละ Client มี Overlay แยก ไม่ปนกัน
• GitOps: ใช้ ArgoCD ทุก Deploy ผ่าน Git Review ได้
• Template: สร้าง Client Template Onboard ไว ภายใน 30 นาที
• Validate: ตรวจสอบ Kustomize Output ก่อน Apply ทุกครั้ง

Kustomize คืออะไร

Kubernetes Configuration Template-free Overlay Pattern Base kustomization.yaml Resources Patches Generators kubectl apply -k GitOps ArgoCD Flux

สรุป

Kustomize Overlay Freelance IT Career Kubernetes Configuration Base Overlay Environment GitOps ArgoCD Multi-client Template Portfolio Production Workflow