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Helm Package Manager

Updated May 21, 2022 ·

Pre-requisites​

  • A basic understanding of Kubernetes
  • Experience in deploying Kubernetes resources

Helm​

Helm is the Kubernetes package manager that simplifies package installation and manages dependencies. In a typical 3-tier architecture, each tier consists of a Deployment, ConfigMap, and Service, as shown below:

Before Helm, each of these components required running separate manifests:

kubectl apply -f frontend-deployment.yml 
kubectl apply -f frontend-configmap.yml 
kubectl apply -f frontend-service.yml 

kubectl apply -f app-deployment.yml 
kubectl apply -f app-configmap.yml 
kubectl apply -f app-service.yml 

kubectl apply -f data-deployment.yml 
kubectl apply -f data-configmap.yml 
kubectl apply -f data-service.yml

This process can be tedious and raises questions like:

  • How to parameterize?
  • How to add application lifecycle hooks?
  • How to manage versions of related resources?

This is where Helm helps. Helm uses charts (similar to Linux packages) to bundle all the necessary parts for a Kubernetes deployment. With Helm, you can deploy multiple resources with a single command.

Benefits of Helm:

  • Simplifies deployments by running everything in one go
  • Tracks versioned history of changes
  • Easy to create and share charts
  • Charts can be stored in a repository

To learn more, visit the official Helm website.

Concepts​

ConceptDescription
ChartContains all components needed to deploy a Kubernetes cluster.
TemplatesComponents that make up a chart.
ConfigOptional configurations to override default settings.
ReleaseA running instance of a chart.
Chart RepositoryA centralized location for storing and sharing charts.

Helm 2 vs. Helm 3​

Helm 3 introduces several differences from Helm 2:

  • Helm 2 uses a different architecture and CLI command structure.
  • Helm 2 charts are compatible with Helm 3.
  • Helm 2 relies on a "Tiller" component for authentication.
  • Helm 3 communicates directly with the Kubernetes API server.
  • Helm 3 uses the same credentials as those in the .kube/config file.

Architecture​

  • Helm Client:

    • Manages charts and releases.
    • Sends requests to the Kubernetes API server.
    • Handles install, upgrade, and uninstall commands.

  • Helm Library:

    • Manages operations with the Kubernetes API server.
    • Handles communication between Helm client and Kubernetes.
    • Handles chart installations and upgrades.
    • Executes Helm operations within Kubernetes.

Setting up Helm​

Helm can be installed from source or pre-built binaries. Here's how to set it up:

Install Helm​

For Windows with WSL2 (Ubuntu), run these commands:

curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

For auto-completion, use:

source <(helm completion bash)
echo "source <(helm completion bash)" >> ~/.bash_profile

Initialize a Repository​

With Helm v3, no repositories are installed by default. Add a repository with:

helm repo add stable https://charts.helm.sh/stable

Add another repo (e.g., Bitnami):

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

To list added repositories:

helm repo list

Update the repositories:

helm repo update

Search for charts in the repositories:

helm search repo

Deploy a Sample Chart​

Install a Redis chart:

helm install my-test-redis1 bitnami/redis

Check running pods:

kubectl get pods

List deployed charts:

helm ls

Delete the Chart​

Uninstall a chart:

helm uninstall my-test-redis1