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Aisalkyn Aidarova
Aisalkyn Aidarova

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Helm for DevOps Engineers

#beginners #devops #kubernetes #tooling

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1️⃣ What is Helm? (Conceptual Foundation)

Helm is an application package manager for Kubernetes.

Helm allows DevOps teams to define, install, upgrade, configure, version, and rollback Kubernetes applications using reusable packages called charts.

Key clarification

  • Helm does NOT replace Kubernetes
  • Helm does NOT replace kubectl
  • Helm operates on top of Kubernetes

2️⃣ Why Helm Was Created (Historical Context)

Kubernetes problem (early days)

Before Helm:

  • Teams manually applied YAML files
  • Each environment had duplicated YAML
  • No upgrade tracking
  • No rollback
  • No standard way to share apps

Example:

deployment-dev.yaml
deployment-prod.yaml
deployment-prod-v2.yaml
deployment-prod-final.yaml
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This caused:

  • Configuration drift
  • Human error
  • Broken production deployments
  • Impossible rollbacks

Helm’s purpose

Helm was created to:

  • Package Kubernetes applications
  • Provide version control for deployments
  • Enable repeatable installs
  • Simplify upgrades
  • Enable rollback

Helm is now a CNCF project, used industry-wide.

3️⃣ Helm Mental Model (Very Important)

Think of Helm like this:

World Tool
Linux OS apt / yum
Docker docker-compose
Kubernetes Helm

Kubernetes manages resources
Helm manages applications

4️⃣ Helm Architecture (Deep Dive)

Helm v3 Architecture (modern)

Helm is:

  • Client-side only
  • No server component
  • No Tiller (removed in v3)

How Helm works internally

  1. Helm reads a chart
  2. Helm merges:
  • values.yaml
  • user overrides (-f, --set)
    1. Helm renders templates → pure YAML
    2. Helm sends YAML to Kubernetes API
    3. Kubernetes creates resources
    4. Helm stores release metadata in Secrets

Where Helm stores state

Helm stores release state in:

Secret:
sh.helm.release.v1.<release>.v<number>
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This contains:

  • Chart version
  • Values
  • Rendered manifests
  • Revision history

This is how rollback works.

5️⃣ Helm Core Components (VERY IMPORTANT)

5.1 Chart

A chart is a Helm package.

It is:

  • A folder
  • With a defined structure
  • Versioned
  • Shareable

Example:

myapp/
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5.2 Chart.yaml

Metadata about the chart:

name: myapp
description: A sample application
version: 1.2.0
appVersion: "2.1.4"
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Important distinction

  • version → chart version
  • appVersion → application version

DevOps interview trap: many people confuse these.

5.3 values.yaml

This is the configuration interface of the chart.

replicaCount: 3

image:
  repository: myorg/myapp
  tag: "1.0.0"

service:
  type: ClusterIP
  port: 80
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Why it matters:

  • Same chart
  • Different environments
  • No YAML duplication

5.4 Templates

Templates are Kubernetes YAML files with Go templating.

Example:

replicas: {{ .Values.replicaCount }}
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Advanced features:

  • Conditionals (if)
  • Loops (range)
  • Includes
  • Helpers

⚠️ DevOps rule:

Templates should be simple. Logic belongs in apps, not Helm.

5.5 Release

A release is a deployed instance of a chart.

You can deploy:

  • Same chart
  • Multiple times
  • With different names and values 
helm install app-dev ./chart
helm install app-prod ./chart
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Each release is tracked independently.

6️⃣ Helm Lifecycle (Install → Upgrade → Rollback)

Install 

helm install myapp ./chart
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Creates:

  • Kubernetes resources
  • Release metadata

Upgrade 

helm upgrade myapp ./chart
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Helm:

  • Calculates diff
  • Applies changes
  • Stores new revision

Rollback 

helm rollback myapp 2
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Helm:

  • Restores old manifests
  • Reapplies them

⚠️ Important:
Helm rollbacks Kubernetes objects, not database data.

7️⃣ Who Uses Helm in Real Companies?

Roles

  • DevOps Engineers
  • Platform Engineers
  • SREs
  • Cloud Infrastructure Teams

Responsibilities

  • Managing application deployments
  • Standardizing environments
  • Reducing human error
  • Supporting GitOps

8️⃣ When DevOps Use Helm (Real Scenarios)

Scenario Why Helm
Production apps Rollback safety
Microservices Standardization
Monitoring stacks Large YAML sets
Databases Stateful config
GitOps Declarative deployment
Multi-env values.yaml overrides

9️⃣ Helm in GitOps (Industry Standard)

Helm is commonly used with Argo CD.

GitOps flow 

Git (Helm Chart)
↓
Argo CD
↓
Kubernetes
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  • Helm defines application structure
  • Argo CD controls deployment timing & sync

This is how real production clusters work.

🔟 Helm Command Reference (DevOps Daily Use)

Repo management 

helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update
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Search 

helm search repo nginx
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Install / upgrade 

helm upgrade --install app bitnami/nginx
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Inspect 

helm status app
helm history app
helm get values app
helm get manifest app
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1️⃣1️⃣ Helm Troubleshooting (Production-Level)

Issue 1: Chart fails 

helm install app ./chart --dry-run --debug
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Always debug before installing.

Issue 2: Wrong configuration 

helm get values app
helm get manifest app
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Compare rendered YAML vs expectation.

Issue 3: Pods crash

Helm is not responsible for runtime failures.

Use Kubernetes tools:

kubectl describe pod
kubectl logs pod
kubectl events
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Issue 4: Bad upgrade 

helm rollback app 1
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This is why Helm is critical in production.

1️⃣2️⃣ Helm Best Practices (From Industry)

  • One chart per application
  • Separate values per environment
  • No secrets in values.yaml
  • Use external secret managers
  • Keep templates readable
  • Lint charts: 
helm lint .
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1️⃣3️⃣ When NOT to Use Helm

  • Very small demos
  • Single YAML experiments
  • When platform team enforces raw YAML
  • When only patching is needed (use Kustomize)

1️⃣4️⃣ Interview-Level Summary (Memorize)

Helm is a Kubernetes package manager that allows DevOps teams to manage complex applications with versioning, upgrades, rollbacks, and environment-specific configuration.

📚 References & Sources (Where This Info Comes From)

This lecture is based on:

Official documentation

CNCF

GitOps

Industry practice

  • Kubernetes production deployments
  • Platform engineering patterns

  • Real DevOps workflows used at:

    • Cloud providers
    • FinTech
    • SaaS companies
    • Enterprise Kubernetes platforms

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