Helm Package Manager

Helm cheatsheet — install, upgrade, rollback Kubernetes charts. helm install, helm upgrade --install, helm rollback, helm template, helm values. Full Helm reference.

6 min read

What it is

Helm is a package manager for Kubernetes that helps you define, install, and upgrade even the most complex Kubernetes applications.

Installation

Linux

curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 | bash

macOS

brew install helm

Windows (using Chocolatey)

choco install kubernetes-helm

Windows (using Scoop)

scoop install helm

Core Concepts

Chart: A Helm package. It contains all the resource definitions needed to run an application, a tool, or a service in Kubernetes. Charts are versioned and can be shared.
Repository: A place where charts are stored and shared. Helm can interact with chart repositories to fetch charts.
Release: An instance of a chart running in a Kubernetes cluster. A chart can be released multiple times in a cluster, and each release can have a different configuration.

Commands / Usage

Creating and Managing Charts

helm create mychart: Create a new chart with a default directory structure and boilerplate.
```
helm create my-nginx-chart
```

helm package mychart: Package a chart directory into a chart archive (.tgz file).

helm package my-nginx-chart
# Output: Successfully packaged chart and saved it to: my-nginx-chart-0.1.0.tgz

helm install <release-name> <chart-path-or-repo>: Install a chart into Kubernetes.

helm install my-nginx ./my-nginx-chart
# Output: NAME: my-nginx LAST DEPLOYED: ... STATUS: deployed REVISION: 1 ...

helm install bitnami/nginx --version 15.4.1
# Output: NAME: some-nginx LAST DEPLOYED: ... STATUS: deployed REVISION: 1 ...

helm upgrade <release-name> <chart-path-or-repo>: Upgrade an existing release to a new version or with a new configuration.
```
helm upgrade my-nginx ./my-nginx-chart --version 0.2.0
# Output: UPGRADE SUCCESSFUL: ...
```

helm uninstall <release-name>: Uninstall a release.

helm uninstall my-nginx
# Output: release "my-nginx" uninstalled

helm rollback <release-name> <revision-number>: Roll back a release to a previous revision.
```
helm rollback my-nginx 1
# Output: rolled back my-nginx to ...
```

helm list: List all releases in the current namespace.

helm list
# Output: NAME    NAMESPACE   REVISION    UPDATED STATUS      CHART           APP VERSION
# my-nginx    default     2           ...     deployed    my-nginx-chart-0.1.0  ...

helm list -a: List all releases in all namespaces.
```
helm list -a
```

helm history <release-name>: Show the history of a release.

helm history my-nginx
# Output: REVISION    UPDATED                 STATUS      CHART               DESCRIPTION
# 1           ...         deployed                ...         my-nginx-chart-0.1.0  Install complete
# 2           ...         deployed                ...         my-nginx-chart-0.1.0  Upgrade "my-nginx"

helm status <release-name>: Show the status of a release.

helm status my-nginx
# Output: NAME: my-nginx LAST DEPLOYED: ... STATUS: deployed REVISION: 2 ...

Managing Repositories

helm repo add <repo-name> <repo-url>: Add a chart repository.

helm repo add bitnami https://charts.bitnami.com/bitnami
# Output: "bitnami" has been added to your repositories

helm repo list: List all configured chart repositories.

helm repo list
# Output: NAME    URL
# bitnami https://charts.bitnami.com/bitnami

helm repo update: Update the local cache of chart repositories.
```
helm repo update
# Output: ... updated.
```

helm repo remove <repo-name>: Remove a chart repository.

helm repo remove bitnami
# Output: "bitnami" has been removed from your repositories

Searching for Charts

helm search repo <keyword>: Search for charts in repositories.

helm search repo nginx
# Output: NAME            CHART VERSION   APP VERSION DESCRIPTION
# bitnami/nginx   15.4.1          1.21.6          NGINX Open Source is a web server that can be also used as a reverse proxy...

helm search repo <repo-name>/<chart-name>: Search for a specific chart in a repository.

helm search repo bitnami/redis
# Output: NAME            CHART VERSION   APP VERSION DESCRIPTION
# bitnami/redis   17.7.1          7.0             Redis is an open source, in-memory data structure store...

helm search hub <keyword>: Search for charts on Artifact Hub.

helm search hub prometheus
# Output: NAME                               CHART VERSION   APP VERSION   PLATFORM    REPOSITORY
# prometheus-community/prometheus        22.0.1          2.45.0        kubernetes    prometheus-community
# ...

Inspecting Charts

helm show chart <chart-path-or-repo>: Show information about a chart.
```
helm show chart bitnami/nginx
# Output: apiVersion: v2 ...
```
helm show values <chart-path-or-repo>: Show the default values for a chart.
```
helm show values bitnami/nginx
# Output: replicaCount: 1 ...
```
helm show readme <chart-path-or-repo>: Show the README for a chart.
```
helm show readme bitnami/nginx
# Output: # NGINX Open Source ...
```

Customizing Installations

helm install <release-name> <chart> -f my-values.yaml: Install a chart using a custom values file.

# Create a file named custom-values.yaml with:
# replicaCount: 3
# service:
#   type: LoadBalancer

helm install my-custom-nginx ./my-nginx-chart -f custom-values.yaml

helm install <release-name> <chart> --set key1=value1,key2.subkey=value2: Install a chart and override values using --set.
```
helm install my-set-nginx ./my-nginx-chart --set replicaCount=2,service.type=NodePort
```
helm template <release-name> <chart> -f my-values.yaml: Render charts locally to see the Kubernetes manifests without deploying them.
```
helm template my-nginx-preview ./my-nginx-chart -f custom-values.yaml
# Output: --- apiVersion: v1 ...
```

Chart Hooks

helm uninstall <release-name> --no-hooks: Uninstall a release without running delete hooks.
```
helm uninstall my-nginx --no-hooks
```
helm upgrade <release-name> <chart> --atomic: If an upgrade fails, the release is rolled back to the previous version.
```
helm upgrade my-nginx ./my-nginx-chart --atomic
```

Common Patterns

Deploying an application with custom configurations:
```
helm upgrade --install my-app bitnami/redis -f my-redis-values.yaml --namespace dev
```
(This command installs if my-app doesn’t exist, or upgrades if it does. It uses a local my-redis-values.yaml file for configuration and deploys into the dev namespace.)

Finding the latest version of a chart and installing it:

CHART_INFO=$(helm search repo bitnami/nginx --devel --limit 1)
CHART_NAME=$(echo "$CHART_INFO" | awk '{print $1}')
LATEST_VERSION=$(echo "$CHART_INFO" | awk '{print $2}')
helm install my-latest-nginx $CHART_NAME --version $LATEST_VERSION

Rendering a chart to stdout with specific values:

helm template my-app ./my-app-chart --set image.tag=latest --namespace default

Listing releases in a specific namespace:
```
helm list --namespace kube-system
```
Getting the YAML output of a release’s deployed resources:
```
helm get manifest my-nginx
```

Gotchas

Namespaces: By default, Helm operates in the default namespace. Always specify namespaces using --namespace or ensure your kubectl context is set correctly if you want to manage releases in different namespaces.
Release Names: Release names must be unique within a namespace.
Chart Versioning: When upgrading, Helm defaults to the latest chart version. Explicitly specify --version if you need a specific older version to avoid unintended upgrades.
helm install vs helm upgrade: helm install will fail if a release with that name already exists. helm upgrade --install (or helm upgrade -i) is often preferred as it will install the release if it doesn’t exist, or upgrade it if it does.
Helm 2 vs Helm 3: Helm 3 removed the Tiller component, simplifying the architecture. If you encounter older documentation or setups, be aware of the differences. Most modern usage is Helm 3.
Chart Hooks: By default, Helm runs hooks during installation, upgrade, and uninstall. Be mindful of hooks that might interfere with automated processes or require specific conditions to run. Use --no-hooks during uninstall if necessary.