devops

Part 8: Helm - Packaging Kubernetes Applications

Published: (December 30, 2025 at 08:20 PM EST)
7 min read
Source: Dev.to

Source: Dev.to

Series: From “Just Put It on a Server” to Production DevOps
Reading time: 15 minutes
Level: Intermediate

The YAML Duplication Problem

In Part 6 we deployed our SSPP platform to Kubernetes. It works! But look at your k8s/ directory:

k8s/
├── api-deployment.yaml
├── api-service.yaml
├── api-configmap.yaml
├── worker-deployment.yaml
├── worker-configmap.yaml
├── redis-deployment.yaml
├── redis-service.yaml
├── postgres-statefulset.yaml
├── postgres-service.yaml
└── …

Now your manager says:

“We need dev, staging, and prod environments.”

Your first thought is to copy‑paste all YAML files three times:

k8s/
├── dev/
│   ├── api-deployment.yaml   # replicas: 1, resources: small
│   ├── api-service.yaml
│   └── …
├── staging/
│   ├── api-deployment.yaml   # replicas: 2, resources: medium
│   ├── api-service.yaml
│   └── …
└── prod/
    ├── api-deployment.yaml   # replicas: 5, resources: large
    ├── api-service.yaml
    └── …

What changes between environments?

  • Replica counts
  • Resource limits
  • Image tags
  • Database URLs
  • Domain names
  • Storage sizes

What stays the same?

  • Container ports
  • Health‑check paths
  • Service types
  • Label selectors
  • Volume mount paths

You’re copying 80 % identical YAML and changing 20 %.

Then a bug is found: the API health‑check path should be /health instead of /healthz.
Now you need to update it in three places and you miss one. Staging is broken. Users are angry.

This is the YAML duplication problem.

What is Helm?

Helm is a package manager for Kubernetes applications.

Beginner mental model

Helm is like apt‑get (Linux) or Homebrew (macOS) for Kubernetes apps.
Instead of managing 20+ YAML files per environment, you create a Helm chart—a template with variables:

# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Values.name }}
spec:
  replicas: {{ .Values.replicas }}
  template:
    spec:
      containers:
        - name: api
          image: {{ .Values.image.repository }}:{{ .Values.image.tag }}
          resources:
            limits:
              cpu: {{ .Values.resources.cpu }}
              memory: {{ .Values.resources.memory }}

Values files per environment

# values-dev.yaml
name: sspp-api
replicas: 1
image:
  repository: davidbrown77/sspp-api
  tag: dev-latest
resources:
  cpu: "500m"
  memory: "512Mi"
# values-prod.yaml
name: sspp-api
replicas: 5
image:
  repository: davidbrown77/sspp-api
  tag: v1.2.3
resources:
  cpu: "2000m"
  memory: "4Gi"

Deploy with Helm

# Dev
helm install sspp-api ./charts/api -f values-dev.yaml

# Prod
helm install sspp-api ./charts/api -f values-prod.yaml

Same template, different values. DRY (Don’t Repeat Yourself) for Kubernetes.

Helm Concepts

Charts

A Helm chart is a package of Kubernetes manifests.

Structure

charts/api/
├── Chart.yaml          # metadata (name, version)
├── values.yaml         # default values
├── templates/          # templated Kubernetes manifests
│   ├── deployment.yaml
│   ├── service.yaml
│   ├── configmap.yaml
│   └── ingress.yaml
└── charts/             # dependencies (sub‑charts)

Values

values.yaml defines default configuration:

replicaCount: 3

image:
  repository: davidbrown77/sspp-api
  tag: latest
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 3000

resources:
  limits:
    cpu: 1000m
    memory: 1Gi
  requests:
    cpu: 500m
    memory: 512Mi

Override values

helm install sspp-api ./charts/api \
  --set replicaCount=5 \
  --set image.tag=v1.2.3

Or use a separate values file:

helm install sspp-api ./charts/api -f prod-values.yaml

Templates

Templates use Go templating syntax:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ include "api.fullname" . }}
  labels:
    {{- include "api.labels" . | nindent 4 }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      {{- include "api.selectorLabels" . | nindent 6 }}
  template:
    metadata:
      labels:
        {{- include "api.selectorLabels" . | nindent 8 }}
    spec:
      containers:
        - name: {{ .Chart.Name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          ports:
            - name: http
              containerPort: {{ .Values.service.port }}

Template functions

  • {{ .Values.replicaCount }} – access values
  • {{ include "helper" . }} – reuse templates
  • {{- if .Values.enabled }} – conditionals
  • {{- range .Values.items }} – loops

Creating a Helm Chart for SSPP API

Initialize the chart

cd infrastructure
helm create charts/api

Define Chart.yaml

apiVersion: v2
name: sspp-api
description: Sales Signal Processing Platform API
type: application
version: 1.0.0
appVersion: "1.0.0"

Create templates

templates/deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Values.name }}
  labels:
    app: {{ .Values.name }}
spec:
  replicas: {{ .Values.replicas }}
  selector:
    matchLabels:
      app: {{ .Values.name }}
  template:
    metadata:
      labels:
        app: {{ .Values.name }}
    spec:
      containers:
        - name: {{ .Values.name }}
          image: "{{ .Values.image.repository }}:{{ .Values.image.tag }}"
          ports:
            - containerPort: {{ .Values.containerPort }}
          resources:
            limits:
              cpu: {{ .Values.resources.cpu }}
              memory: {{ .Values.resources.memory }}

(Add additional templates for Service, ConfigMap, Ingress, etc., following the same pattern.)

Deploy

# Dev
helm install sspp-api ./charts/api -f values-dev.yaml

# Staging
helm install sspp-api ./charts/api -f values-staging.yaml

# Prod
helm install sspp-api ./charts/api -f values-prod.yaml

Now you have a single source of truth for your manifests, with environment‑specific values kept separate—eliminating the YAML duplication problem.

Helm Charts for SSPP API & Worker

templates/deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: {{ .Values.name }}
  labels:
    app: {{ .Values.name }}
spec:
  replicas: {{ .Values.replicaCount }}
  selector:
    matchLabels:
      app: {{ .Values.name }}
  template:
    metadata:
      labels:
        app: {{ .Values.name }}
    spec:
      containers:
        - name: api
          image: {{ .Values.image.repository }}:{{ .Values.image.tag }}
          ports:
            - containerPort: 3000
          env:
            - name: DATABASE_URL
              value: {{ .Values.database.url }}
            - name: REDIS_URL
              value: {{ .Values.redis.url }}
            {{- if .Values.env }}
            {{- range $key, $value := .Values.env }}
            - name: {{ $key }}
              value: {{ $value | quote }}
            {{- end }}
            {{- end }}
          resources:
            limits:
              cpu: {{ .Values.resources.limits.cpu }}
              memory: {{ .Values.resources.limits.memory }}
            requests:
              cpu: {{ .Values.resources.requests.cpu }}
              memory: {{ .Values.resources.requests.memory }}
          livenessProbe:
            httpGet:
              path: /health
              port: 3000
            initialDelaySeconds: 30
            periodSeconds: 10
          readinessProbe:
            httpGet:
              path: /health
              port: 3000
            initialDelaySeconds: 5
            periodSeconds: 5

templates/service.yaml

apiVersion: v1
kind: Service
metadata:
  name: {{ .Values.name }}
  labels:
    app: {{ .Values.name }}
spec:
  type: {{ .Values.service.type }}
  ports:
    - port: {{ .Values.service.port }}
      targetPort: 3000
      protocol: TCP
      name: http
  selector:
    app: {{ .Values.name }}

Values Files

values.yaml

name: sspp-api
replicaCount: 3

image:
  repository: davidbrown77/sspp-api
  tag: latest
  pullPolicy: IfNotPresent

service:
  type: ClusterIP
  port: 3000

database:
  url: "postgresql://user:pass@postgres:5432/sspp"

redis:
  url: "redis://redis:6379"

resources:
  limits:
    cpu: "1000m"
    memory: "1Gi"
  requests:
    cpu: "500m"
    memory: "512Mi"

env: {}

values-dev.yaml

name: sspp-api
replicaCount: 1
image:
  tag: dev-latest
resources:
  limits:
    cpu: "500m"
    memory: "512Mi"
  requests:
    cpu: "250m"
    memory: "256Mi"

values-prod.yaml

name: sspp-api
replicaCount: 5
image:
  tag: v1.2.3
  pullPolicy: Always
resources:
  limits:
    cpu: "2000m"
    memory: "4Gi"
  requests:
    cpu: "1000m"
    memory: "2Gi"
env:
  LOG_LEVEL: "info"
  NODE_ENV: "production"

Deploying with Helm

Install

# Dev environment
helm install sspp-api ./charts/api -f values-dev.yaml

# Prod environment (different namespace)
helm install sspp-api ./charts/api \
  -f values-prod.yaml \
  -n production \
  --create-namespace

Upgrade

# Update image tag
helm upgrade sspp-api ./charts/api \
  --set image.tag=v1.3.0 \
  --reuse-values

Rollback

# Rollback to previous release
helm rollback sspp-api

# Rollback to specific revision
helm rollback sspp-api 3

List Releases

helm list
helm list -n production

Get Values

# See computed values
helm get values sspp-api

# See all values (including defaults)
helm get values sspp-api --all

Helm for Worker Service

Create a similar chart for the worker:

helm create charts/worker

Key differences from API

  • No Service – the worker doesn’t expose HTTP.
  • Different environment variables.
  • Different resource requirements.

values.yaml (worker)

name: sspp-worker
replicaCount: 2

image:
  repository: davidbrown77/sspp-worker
  tag: latest

redis:
  url: "redis://redis:6379"

database:
  url: "postgresql://user:pass@postgres:5432/sspp"

resources:
  limits:
    cpu: "1000m"
    memory: "2Gi"
  requests:
    cpu: "500m"
    memory: "1Gi"

Benefits of Helm

  • ✅ DRY Principle – One template, multiple environments. Change once, deploy everywhere.
  • ✅ Version Control – Track changes to chart versions; rollback to any previous release.
  • ✅ Parameterization – Override any value at deployment; no hard‑coded configuration.
  • ✅ Package Management – Share charts via Helm repositories; reuse community charts (PostgreSQL, Redis, etc.).
  • ✅ Release Management – Track deployment history; easy rollbacks.

What’s Next?

Helm solves packaging and templating, but we still have deployment problems:

  • ❌ Manual deployments – someone must run helm upgrade.
  • ❌ No Git sync – cluster state can drift from Git.
  • ❌ No automation – still need CI/CD triggers.
  • ❌ Configuration drift – manual kubectl changes go untracked.

In Part 9, we’ll add GitOps with Argo CD.

You’ll learn:

  • Git as the single source of truth (not your laptop).
  • Automatic sync from Git → Cluster.
  • Self‑healing (Argo CD reverts manual changes).
  • One‑click rollbacks through UI.
  • Deployment history and audit trails.
  • Progressive delivery (blue/green, canary).

Spoiler: Push to Git → Argo CD deploys automatically. This is GitOps.

Try It Yourself

Create Helm charts for all SSPP services:

  1. API chart – Deployment + Service + Ingress.
  2. Worker chart – Deployment only.
  3. Redis chart – Use bitnami/redis from Helm Hub (or create your own).
  4. PostgreSQL chart – Use bitnami/postgresql from Helm Hub (or create your own).

Happy charting! 🚀

# PostgreSQL

## Test multi‑environment setup

```bash
# Deploy dev
helm install sspp ./charts/api -f values-dev.yaml -n dev --create-namespace

# Deploy prod
helm install sspp ./charts/api -f values-prod.yaml -n production --create-namespace

# Compare
kubectl get pods -n dev
kubectl get pods -n production

Bonus: Package your chart and push to a Helm repository (GitHub Pages, ChartMuseum, or OCI registry).


## Next: Automating Deployments

In [Part 9](//./09-argocd-gitops.md) we’ll solve the manual‑
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