You already know what a chart repository is and how to install a chart off an existing repo. So let us consider how we would go about creating a chart repo and serving it, as well as a deep-dive into chart repositories.
While chart repositories such as ArtifactHub exist, you may want to create your own chart repositories. A chart repository is simply an HTTP server whcih has an index.yaml in it. The HTTP server does not need to be a physical server, and can instead be a GCS bucket, S3 bucket, or even something like GitHub pages. Going back to the index.yaml, this is neccessary to hold a reference to all charts in a repo, and is generally hosted on the same server.
To create this file, use
helm repo indexThis generates an index file. If you have packages charts (such as alpine) present in the local directory where you run this command, those charts will be taken into consideration.
Now that your chart repo structure is complete, let's go ahead and host the chart. There are a ton of ways to achieve this, and we will be using GitHub pages. This official guide should be able to start you off with creating a GitHub page.
Once your page is setup, there are some other steps that need completing in order for you to convert it to a Helm chart repo. You need to use chart releaser. Chart releaser is a GitHub action workflow, which is essentially a pipeline you can use to automate releases. Read more about GitHub action here.
You would likely have created a GitHub repository at this point. Introduce a folder called charts at the top level, then place all your charts there. It is also advisable to have a readme at the root level which acts as a guide to anyone using your repo. Once this is done, you can start setting up your GitHub workflow.
The chart releaser action will convert your GitHub repo to a Helm chart repo. Every time you push to master, every chart present in your project (inside the charts folder) is checked. If there is a new version, a GitHub release is created with the name of the chart version, and an artifact is created. The index.yaml is created (or updated) with the relevant metadata, and this is finally hosted on your GitHub page. Note that you can use Helm testing actions to ensure nothing breaks during this automated process.