Kubernetes Helm

Helm is a tool for managing Kubernetes charts. Charts are packages of pre-configured Kubernetes resources.

Use Helm to...

• Find and use popular software packaged as Kubernetes charts
• Share your own applications as Kubernetes charts
• Create reproducible builds of your Kubernetes applications
• Intelligently manage your Kubernetes manifest files
• Manage releases of Helm packages

Helm in a Handbasket

Helm is a tool that streamlines installing and managing Kubernetes applications. Think of it like apt/yum/homebrew for Kubernetes.

• Helm has two parts: a client (helm) and a server (tiller)
• Tiller runs inside of your Kubernetes cluster, and manages releases (installations) of your charts.
• Helm runs on your laptop, CI/CD, or wherever you want it to run.
• Charts are Helm packages that contain at least two things:
  • A description of the package (Chart.yaml)
  • One or more templates, which contain Kubernetes manifest files
• Charts can be stored on disk, or fetched from remote chart repositories (like Debian or RedHat packages)

Using Helm is as easy as this:

$ helm init                            # Initialize Helm as well as the Tiller server
$ helm install docs/examples/alpine    # Install the example Alpine chart
happy-panda                            # <-- That's the name of your release
$ helm list                            # List all releases
happy-panda
quiet-kitten

Install

Download a release tarball of helm and tiller for your platform. Unpack the helm and tiller binaries and add them to your PATH and you are good to go!

Install from source

To install Helm from source, follow this process:

Make sure you have the prerequisites:

• Go 1.6
• A running Kubernetes cluster
• kubectl properly configured to talk to your cluster
• Glide 0.10 or greater with both git and mercurial installed.

1. Properly set your $GOPATH
2. Clone (or otherwise download) this repository into $GOPATH/src/k8s.io/helm
3. Run make bootstrap build

You will now have two binaries built:

• bin/helm is the client
• bin/tiller is the server

From here, you can run bin/helm and use it to install a recent snapshot of Tiller. Helm will use your kubectl config to learn about your cluster.

For development on Tiller, you can locally run Tiller, or you build a Docker image (make docker-build) and then deploy it (helm init -i IMAGE_NAME).

The documentation folder contains more information about the architecture and usage of Helm/Tiller.

The History of the Project

Kubernetes Helm is the merged result of Helm Classic and the Kubernetes port of GCS Deployment Manager. The project was jointly started by Google and Deis, though it is now part of the CNCF.

Differences from Helm Classic:

• Helm now has both a client (helm) and a server (tiller). The server runs inside of Kubernetes, and manages your resources.
• Helm's chart format has changed for the better:
  • Dependencies are immutable and stored inside of a chart's charts/ directory.
  • Charts are strongly versioned using SemVer 2
  • Charts can be loaded from directories or from chart archive files
  • Helm supports Go templates without requiring you to run generate or template commands.
  • Helm makes it easy to configure your releases -- and share the configuration with the rest of your team.
• Helm chart repositories now use plain HTTP instead of Git/GitHub. There is no longer any GitHub dependency.
  • A chart server is a simple HTTP server
  • Charts are referenced by version
  • The helm serve command will run a local chart server, though you can easily use object storage (S3, GCS) or a regular web server.
  • And you can still load charts from a local directory.
• The Helm workspace is gone. You can now work anywhere on your filesystem that you want to work.