Lab 4 - Helm Repositories

A key aspect of providing an application means sharing with others. Sharing can be direct counsumption (by users or in CI/CD pipelines) or as a dependency for other charts. If people can't find your app then they can't use it.

A means of sharing is a chart repository, which is a location where packaged charts can be stored and shared. As the chart repository only applies to Helm, we will just look at the usage and storage of Helm charts.

Using charts from a public repository

Helm charts can be available on a remote repository or in a local environment/repository. The remote repositories can be public like Bitnami Charts or IBM Helm Charts, or hosted repositories like on Google Cloud Storage or GitHub. Refer to Helm Chart Repository Guide for more details. You can learn more about the structure of a chart repository by examining the chart index file in this lab.

In this part of the lab, we show you how to install the guestbook chart from the Helm101 repo.

1. Check the repositories configured on your system:

   helm repo list

   The output should be similar to the following:

   $ helm repo list
   Error: no repositories to show

   Note: Chart repositories are not installed by default with Helm v3. It is expected that you add the repositories for the charts you want to use. The Helm Hub provides a centralized search for publicly available distributed charts. Using the hub you can identify the chart with its hosted repository and then add it to your local respoistory list. The Helm chart repository like Helm v2 is in "maintenance mode" and will be deprecated by November 13, 2020. See the project status for more details.

2. Add helm101 repo:

   helm repo add helm101 https://ibm.github.io/helm101/

   Should generate an output as follows:

   $ helm repo add helm101 https://ibm.github.io/helm101/
   "helm101" has been added to your repositories

   You can also search your repositories for charts by running the following command:

   helm search repo helm101

   $ helm search repo helm101
   NAME              CHART VERSION  APP VERSION DESCRIPTION
   helm101/guestbook 0.2.1                      A Helm chart to deploy Guestbook three tier web...

3. Install the chart

   As mentioned we are going to install the guestbook chart from the Helm101 repo. As the repo is added to our local respoitory list we can reference the chart using the repo name/chart name, in other words helm101/guestbook. To see this in action, you will install the application to a new namespace called repo-demo.

   If the repo-demo namespace does not exist, create it using:

   kubectl create namespace repo-demo

   Now install the chart using this command:

   helm install guestbook-demo helm101/guestbook --namespace repo-demo

   The output should be similar to the following:

   $helm install guestbook-demo helm101/guestbook --namespace repo-demo
   NAME: guestbook-demo
   LAST DEPLOYED: Tue Feb 25 15:40:17 2020
   NAMESPACE: repo-demo
   STATUS: deployed
   REVISION: 1
   TEST SUITE: None
   NOTES:
   1. Get the application URL by running these commands:
     NOTE: It may take a few minutes for the LoadBalancer IP to be available.
           You can watch the status of by running 'kubectl get svc -w guestbook-demo --namespace repo-demo'
     export SERVICE_IP=$(kubectl get svc --namespace repo-demo guestbook-demo -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
     echo http://$SERVICE_IP:3000

   Check that release deployed as expected as follows:

   $ helm list -n repo-demo
   NAME           NAMESPACE   REVISION UPDATED                                   STATUS   CHART            APP VERSION
   guestbook-demo repo-demo   1        2020-02-25 15:40:17.627745329 +0000 UTC   deployed guestbook-0.2.1

Conclusion

This lab provided you with a brief introduction to the Helm repositories to show how charts can be installed. The ability to share your chart means ease of use to both you and your consumers.