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Omar Ahmed
Omar Ahmed

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Helm

#devops #kubernetes

What is Helm?

Helm is the package manager for Kubernetes. Think of it like apt for Ubuntu or npm for Node.js. Instead of writing many YAML files and running kubectl apply on each, you bundle them into a chart and install the whole app with one command.

  • Packaging applications as "Charts"
  • Managing complex deployments
  • Handling versioning and rollbacks
  • Templating Kubernetes manifests

Helm Architecture & Components

Helm installs charts into Kubernetes, creating a new release for each installation. And to find new charts, you can search Helm chart repositories.

  • Repository where charts are stored and shared (like Docker Hub for containers)
  • Chart a package containing Kubernetes manifests as templates.
  • Release an instance of a chart running in your cluster
  • Values configuration that fills in the template variables

Chart Structure: 

mychart/
├── Chart.yaml          # Chart metadata
├── values.yaml         # Default configuration values
├── templates/          # Kubernetes manifest templates
│   ├── deployment.yaml
│   ├── service.yaml
│   └── _helpers.tpl    # Template helpers
└── charts/            # Dependencies
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Key Files:

  • Chart.yaml: Chart metadata (name, version, description)
  • values.yaml: Default values for template variables
  • templates/: Go templates that generate Kubernetes manifests

Basic Commands 

# Add a repository
helm repo add bitnami https://charts.bitnami.com/bitnami
helm repo update

# Search for charts
helm search repo nginx

# Install a chart (creates a release)
helm install my-nginx bitnami/nginx

# List releases
helm list

# Upgrade a release
helm upgrade my-nginx bitnami/nginx --set replicaCount=3

# Rollback
helm rollback my-nginx 1

# Uninstall
helm uninstall my-nginx
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Your First Chart:

helm create mychart
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This generates a directory:

mychart/
  Chart.yaml          # metadata (name, version, description)
  values.yaml         # default configuration
  templates/          # Kubernetes manifests with Go templating
    deployment.yaml
    service.yaml
    _helpers.tpl
  charts/             # subchart dependencies
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Hands-On Practice

  • Prerequisites: kubernetes Cluster , kubectl , helm

Basic Repository and Install 

# Add the repo
helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm repo add grafana https://grafana.github.io/helm-charts
helm repo update

# Remove the repo
helm repo list
helm repo remove bitnami

# See what's available
helm search repo kube-prometheus-stack
helm search repo kube-prometheus-stack --versions | head -5

# Inspect before installing
helm show chart prometheus-community/kube-prometheus-stack # inspecting a Helm chart’s metadata without installing it.
helm show values prometheus-community/kube-prometheus-stack > default-values.yaml

# Install with defaults
kubectl create namespace monitoring
helm search repo kube-prometheus-stack --versions | head -5
helm install monitoring prometheus-community/kube-prometheus-stack \
  --namespace monitoring \
  --version 65.1.1 # 65.1.1 is the Helm chart version, not the app version.

# Watch it come up
kubectl get pods -n monitoring -w
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Once pods are running, access the UIs: 

## Once pods are running, access the UIs:
# Grafana (default admin / prom-operator)
kubectl port-forward -n monitoring svc/monitoring-grafana 3000:80

# Prometheus
kubectl port-forward -n monitoring svc/monitoring-kube-prometheus-prometheus 9090:9090

# Alertmanager
kubectl port-forward -n monitoring svc/monitoring-kube-prometheus-alertmanager 9093:9093
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Inspect the Release 

# Inspect the Release
helm list -n monitoring
helm status monitoring -n monitoring # get usernames and passwords

helm get values monitoring -n monitoring
helm get values monitoring -n monitoring --all   # includes defaults
helm get manifest monitoring -n monitoring | head -50 # Fetches the full Kubernetes YAML manifests for the release named monitoring
helm history monitoring -n monitoring
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Upgrade and Clean up 

# Upgrade with --set
helm upgrade monitoring prometheus-community/kube-prometheus-stack \
  --namespace monitoring \
  --set grafana.replicas=2

helm history monitoring -n monitoring

# roll it back
helm rollback monitoring 1 -n monitoring
kubectl get pods -n monitoring -l app.kubernetes.io/name=grafana

# Clean up
helm uninstall monitoring -n monitoring
kubectl get all -n monitoring
kubectl delete namespace monitoring
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Pull the Chart 

# Download the .tgz
helm pull prometheus-community/kube-prometheus-stack --version 65.1.1

# Download AND extract it
helm pull prometheus-community/kube-prometheus-stack \
  --version 65.1.1 \
  --untar \
  --untardir ./charts

ls charts/kube-prometheus-stack/
# Chart.yaml  values.yaml  templates/  charts/  README.md  ...

helm dependency list
ls charts/kube-prometheus-stack/charts/
helm dependency update # download/update dependencies
# Read Chart.yaml: Looks at the dependencies: block 
# Download required charts From the specified repositories
# Store them locally: Inside the charts/ directory of your project
# Generate/update Chart.lock: Locks exact versions

ls charts/kube-prometheus-stack/charts/  # you'll see kube-prometheus-stack-65.1.1.tgz
cat Chart.yaml | grep version
cat Chart.lock       # lock file for your chart dependencies , commit this to Git
# dependencies: exact versions used
# digest: checksum of dependencies (integrity check)
# generated: timestamp
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Build the Chart 

mkdir -p monitoring-stack/environments
tree monitoring-stack
cd monitoring-stack
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Create Chart.yaml

apiVersion: v2
name: company-monitoring
description: Company-wide monitoring stack
type: application
version: 1.0.0
appVersion: "1.0.0"

dependencies:
  - name: kube-prometheus-stack
    version: "65.1.1"
    repository: "https://prometheus-community.github.io/helm-charts"
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helm dependency update
ls charts/
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Create values.yaml

kube-prometheus-stack:
  fullnameOverride: monitoring

  prometheus:
    prometheusSpec:
      retention: 15d
      retentionSize: "45GB"
      serviceMonitorSelectorNilUsesHelmValues: false
      podMonitorSelectorNilUsesHelmValues: false
      ruleSelectorNilUsesHelmValues: false
      resources:
        requests:
          cpu: 200m
          memory: 1Gi
        limits:
          memory: 2Gi

  grafana:
    adminPassword: "grafana123"   # override per environment
    defaultDashboardsTimezone: browser
    sidecar:
      dashboards:
        enabled: true
        label: grafana_dashboard
        searchNamespace: ALL
      datasources:
        enabled: true

  alertmanager:
    alertmanagerSpec:
      resources:
        requests:
          cpu: 50m
          memory: 128Mi

  nodeExporter:
    enabled: true
  kubeStateMetrics:
    enabled: true
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Environment Overrides:

Create environments/values-dev.yaml

kube-prometheus-stack:
  prometheus:
    prometheusSpec:
      retention: 3d
      retentionSize: "8GB"
      resources:
        requests:
          cpu: 100m
          memory: 512Mi

  grafana:
    adminPassword: "admindev123"
    persistence:
      enabled: false

  alertmanager:
    enabled: false
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Create environments/values-prod.yaml

kube-prometheus-stack:
  prometheus:
    prometheusSpec:
      retention: 30d
      retentionSize: "180GB"
      replicas: 2
      resources:
        requests:
          cpu: 1
          memory: 4Gi
        limits:
          memory: 8Gi

  grafana:
    replicas: 2
    adminPassword: "adminprod123"
    persistence:
      enabled: true
      size: 10Gi

  alertmanager:
    alertmanagerSpec:
      replicas: 3
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Lint and Render Before Installing 

# Check for syntax issues
helm lint . # Lint (validate) the Helm chart in the current folder
helm lint . -f environments/values-dev.yaml

# Render locally — no cluster needed
helm template monitoring . -f environments/values-dev.yaml > rendered-dev.yaml

# Dry-run against the cluster (validates against API)
helm install monitoring . \
  --namespace monitoring \
  --create-namespace \
  -f environments/values-dev.yaml \
  --dry-run --debug 2>&1 | head -80
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helm install monitoring . \
  --namespace monitoring \
  --create-namespace \
  -f values.yaml \
  -f environments/values-dev.yaml \
  --rollback-on-failure \
  --timeout 10m

kubectl get secret monitoring-grafana -n monitoring -o jsonpath="{.data.admin-password}" | base64 --decode
kubectl port-forward -n monitoring svc/monitoring-grafana 3000:80

# added replicas to values.dev.yaml
# grafana:
#     replicas: 3

helm upgrade monitoring . \
  --namespace monitoring \
  -f values.yaml \
  -f environments/values-dev.yaml \
  --timeout 10m

# Verify
helm list -n monitoring
kubectl get pods -n monitoring
kubectl get prometheusrules -n monitoring
kubectl get servicemonitors -n monitoring
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Teardown 

kubectl delete ns monitoring 
helm repo remove prometheus-community grafana
helm repo list
helm list -A
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Don't forget to destroy your cloud Kubernetes cluster

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