Tag Archives: Kubernetes

Creating a Helm chart repository

In this post, we’ll learn how to create and work with Helm chart repositories.

A chart repository is an HTTP server that houses an index.yaml file and optionally some packaged charts. Because a chart repository can be any HTTP server that can serve YAML and tar files and can answer GET requests, we have a plethora of options when it comes down to hosting our own chart repository. For example, we can use a Google Cloud Storage (GCS) bucket, Amazon S3 bucket, GitHub Pages, or even create our own web server.

Once the charts are ready and we need to share them, the easiest way to do so is by uploading them to a chart repository. However, Helm does not come with a chart repository while Helm can serve the local repository via “helm serve”.

Github Pages

We can create charts repository using GitHub Pages. It allows us to serve static web pages.

All we need is to host a single index.yaml file along with a bunch of .tgz files.

Create a new Github repository

Though it’s empty repo, let’s just clone it for now:

$ git clone https://github.com/Einsteinish/dummy-helm-charts.git    

Create a helm chart

We need to have the Helm CLI installed and initialized:

$ helm version
Client: &version.Version{SemVer:"v2.16.10", GitCommit:"bceca24a91639f045f22ab0f41e47589a932cf5e", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.16.10", GitCommit:"bceca24a91639f045f22ab0f41e47589a932cf5e", GitTreeState:"clean"}

$ helm3 version
version.BuildInfo{Version:"v3.3.1", GitCommit:"249e5215cde0c3fa72e27eb7a30e8d55c9696144", GitTreeState:"dirty", GoVersion:"go1.15"}    

We’re going to use the directory ./sources/ for the sources of our charts. We need to create charts and copy them into the ./sources/:

$ cd dummy-helm-charts/
$ mkdir sources  

$ tree
.
└── dummy-helm-charts
    ├── README.md
    └── sources
    
$ helm create sources/dummy-chart
Creating sources/dummy-chart

$ tree
.
├── README.md
└── sources
    └── dummy-chart
        ├── Chart.yaml
        ├── charts
        ├── templates
        │   ├── NOTES.txt
        │   ├── _helpers.tpl
        │   ├── deployment.yaml
        │   ├── ingress.yaml
        │   ├── service.yaml
        │   ├── serviceaccount.yaml
        │   └── tests
        │       └── test-connection.yaml
        └── values.yaml
        
$ helm lint sources/*
==> Linting sources/dummy-chart
[INFO] Chart.yaml: icon is recommended

1 chart(s) linted, no failures

Create the Helm chart package

$ helm package sources/*
Successfully packaged chart and saved it to: 
/Users/kihyuckhong/Documents/Minikube/Helm/DUMMY/dummy-helm-charts/dummy-chart-0.1.0.tgz

Create the repository index

A chart repository is an HTTP server that houses an index.yaml file.

The index file contains information about each chart and provides the download URL, for example, https://example.com/charts/alpine-0.1.2.tgz for that chart.

The index file is a yaml file called index.yaml. It contains some metadata about the package, including the contents of a chart’s Chart.yaml file. A valid chart repository must have an index file. The helm repo index command will generate an index file based on a given local directory that contains packaged charts.

$ helm repo index --url https://einsteinish.github.io/helm-chart/ . 

$ tree
.
├── README.md
├── dummy-chart-0.1.0.tgz
├── index.yaml
└── sources
    └── dummy-chart
        ├── Chart.yaml
        ├── charts
        ├── templates
        │   ├── NOTES.txt
        │   ├── _helpers.tpl
        │   ├── deployment.yaml
        │   ├── ingress.yaml
        │   ├── service.yaml
        │   ├── serviceaccount.yaml
        │   └── tests
        │       └── test-connection.yaml
        └── values.yaml


$ cat index.yaml
apiVersion: v1
entries:
  dummy-chart:
  - apiVersion: v1
    appVersion: "1.0"
    created: "2020-10-22T13:11:36.940863-07:00"
    description: A Helm chart for Kubernetes
    digest: c8d82f24fc29d40693a608a1fd8db1c2596a8325ecae62529502a1cbae8677a2
    name: dummy-chart
    urls:
    - https://einsteinish.github.io/helm-chart/dummy-chart-0.1.0.tgz
    version: 0.1.0
generated: "2020-10-22T13:11:36.935738-07:00"

Pushing to Github repository

$ git add .

$ git commit -m "initial commit"
[main 4006e22] initial commit
 12 files changed, 322 insertions(+)
 create mode 100644 dummy-chart-0.1.0.tgz
 create mode 100644 index.yaml
 create mode 100644 sources/dummy-chart/.helmignore
 create mode 100644 sources/dummy-chart/Chart.yaml
 create mode 100644 sources/dummy-chart/templates/NOTES.txt
 create mode 100644 sources/dummy-chart/templates/_helpers.tpl
 create mode 100644 sources/dummy-chart/templates/deployment.yaml
 create mode 100644 sources/dummy-chart/templates/ingress.yaml
 create mode 100644 sources/dummy-chart/templates/service.yaml
 create mode 100644 sources/dummy-chart/templates/serviceaccount.yaml
 create mode 100644 sources/dummy-chart/templates/tests/test-connection.yaml
 create mode 100644 sources/dummy-chart/values.yaml

$ git push origin main
...
To https://github.com/Einsteinish/dummy-helm-charts.git
   9d23dff..4006e22  main -> main    

Setting up Github Pages as a helm chart repository

From “settings” of git repository, scroll down to Github Pages section and configure it as follow:

Click “Save”:

Helm client configuration

To use the charts on the repository, we need to configure their own Helm client using helm repo command:

$ helm repo add dummy https://einsteinish.github.io/dummy-helm-charts
"dummy" has been added to your repositories
~/Documents/Minikube/Helm/DUMMY/dummy-helm-charts $ helm repo list
NAME  	URL                                             
stable	https://kubernetes-charts.storage.googleapis.com
local 	http://127.0.0.1:8879/charts                    
dummy 	https://einsteinish.github.io/dummy-helm-charts

$ helm search dummy
NAME             	CHART VERSION	APP VERSION	DESCRIPTION                
dummy/dummy-chart	0.1.0        	1.0        	A Helm chart for Kubernetes
local/dummy-chart	0.1.0        	1.0        	A Helm chart for Kubernetes

Chart repository updates

Whenever we want to add a new chart to the Helm chart repository, we should regenerate the index.yaml file. The helm repo index command will rebuild the index.yaml file including only the charts that it finds locally. Note that we can use the –merge flag to incrementally add new charts to an existing index.yaml:

$ helm repo index --url https://einsteinish.github.io/dummy-helm-charts/ --merge index