What is HELM?

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By Vijay Singh Khatri

Helm helps you simplify, standardize, and reuse application deployment with Kubernetes. Thus, it improves developer productivity and reduces deployment complexity. Helm in the real world means a type of steering that controls the movement of ships. Similarly, the Helm tool lets Kubernetes operators better manage the Kubernetes cluster that their DevOps application is based on.

Well, this sums up what Helm is all about. To find out more about Helm’s workings, benefits, and importance, read the below-given article.

Helm Overview

Kubernetes is an open-source platform that helps in the management of containerized workloads and services. With time and projects being expanded to new horizons, the Kubernetes has become more complex with the increase in the number of objects it handles.. The objects, pods, persistent volumes, etc., can all be managed easily using Helm. By assembling all the objects into one application, the user can see what they can configure in the application.

With just one click, Helm can be installed with Kubernetes and can be configured as per the organization’s needs. Moreover, users have the flexibility to choose the package and the release version of Helm. The Helm 1.0 version only allows certain parts to be configured, but Helm 2.0 allows developers to customize most of its parts.

Kubernetes can easily install, update, and remove the applications present in the container with the help of Helm. Likewise, it allows developers to convert all the objects in one application and share them as one package to the Kubernetes community. Thus, with the use of Helm, the software vendors can offer their containerized applications to clients with a “single click of button” procedure.

Why Do You Need To Consider Helm?

As previously discussed, applications that use Kubernetes can quickly become complex, resulting in developers spending a lot of time writing and maintaining Kubernetes YAML manifests. Even for simple application deployment, you will at least need 3 YAML manifests that require duplicated and hard-coded values. By using Helm, developers can take another approach to the deployment of applications and package all the different objects in a single package that can be used as a bundled package that consists of an advertised cluster of objects.

Helm is a client/ server-side application and relies on Tiller (helm server) for Helm to be deployed on developers’ clusters. The Helm gets installed when a developer tries to get it installed on a client machine. Tiller only has to receive requests from the client and install the package into the developer’s cluster. Helm is more like an RPM of the DEM packages on Linux, as it provides developers with the ability to package their applications and deliver them to clients as one complete application.

Once you are done installing the Helm, you will need to install production-ready applications such as MongoDB, MySQL, and others, in the Kubernetes cluster with one-line commands written for the Helm tool. You need to install Helm if you work on DevOps and manage your Kubernetes cluster using Kubernetes as it will give you a single interface to install, delete, and modify the objects present in the Kubernetes cluster.

What Are Helm Charts?

When a user is building or deploying an application, Helm charts provide the ability to leverage Kubernetes packages via a click of a button or a single line command. When a user runs the Helm install command, the Tiller server receives the request from the user and performs the installation of the appropriate package. The package defines resources used for installing applications in Kubernetes. These resource definitions are called charts.

How To Create A Helm Chart?

In order to create a Helm chart, you first need to install Helm in your system. Once the installation is complete, all you have to do is write Helm create <chart name>, and it will create a directory that will contain all the files and the directories. The files in the directory are required for the creation of even the most basic helm chart.

Now let’s look at the components of the file tree and try to understand their function.

  • Chart.yml: This file will contain all the information related to your chart that includes its version, name, and description. Which makes it easier to find it when you publish it on an open repository. Moreover, this is the file where you get to set the external dependencies using the dependencies key.
  • values.yaml: This file holds all the default variables which are needed to execute the package transfer.
  • Templates (dir): This file directory holds all the files which you manifest for your Kubernetes implementation. All of the materials presented here will be used to create Kubernetes.
  • If the chart you are currently using depends on another chart you already own, or if you don’t want to use Helm’s default chart library then you can bring the structure from the previously owned chart using this directory.

The dependencies of a chart are installed from the bottom to the top. That means chart A depends on chart B, and chart B depends on chart C. and the installation order will be C>B>A.

Note:– There are some other fields as well which are used for the creation of Helm charts, but most of the time, you will only be using these four directories. Another thing to keep in mind is that when installing the Helm version, always choose 3.0. The 2.0 version of Helm will still work perfectly fine, but it requires a server-side component called Tiller which will tie all your Helm installations to a single cluster.

Hosting A Helm Chart

Helm is a public library that consists of most of the used charts, and it works like a Docker Hub. In addition to this, a developer can create his own chart repository and host it online. If you want to use some repositories, you can download the charts contained in them. As a result, a developer doesn’t have to keep his or her repository cloned forever.

However, if you don’t want people to use your Helm charts from the public library, you can host it on your system and make it private. The Helm chart can be hosted on Azure CR and other hosting services as well. In case you want to store your charts and have a clean UI from where you can manage, then check out the Chart Museum application.

Why Helm Is Vital For Kubernetes Deployment?

If used correctly, Helm has a number of functions that can significantly improve an organization’s CL/CD integration with Kubernetes. Each deployment of the chart used in Kubernetes is a part of the Helm release. Helm automatically retrieves information from Kubernetes and maintains a version history of all your releases. So in the event of an error, a developer can simply roll back the changes using the following command: helm rollback RELEASE_Name.

A number of CL/CD pipeline integration hooks are also provided by Helm to Kubernetes to enable you to makecan in the actions. One of the examples of this integration can be found in the verification of the successful deployment. Using Helm, the developer can find out if code has been correctly executed and if the application is healthy.

Furthermore, Helm allows application configuration during deployment. This means a developer working on a project can specify the resources such as deployments, objects, services etc., that are being used in Kubernetes. Also, it allows environment-specific configurations. As a result, a user can deploy the same Helm chart across multiple environments, and it will work accordingly.

Benefits Of Using Helm Charts

Given below are the advantages of using Helm with Kubernetes and why this integration can save a lot of your time.

1. Automation

If you are not using Helm, you need to create YAML files manually for each application that you want to run in your program. But with the use of Helm charts, Helm takes over the deployment process and deploys applications on the cluster for you. There are a number of templates that are present in the Helm charts that work with Kubernetes resources. With the combination of Helm chart templates and Kubernetes resources, one can quickly create an application.

2. Customizability

A user can customize the Helm chart when they are trying to deploy it on different Kubernetes clusters. The Helm charts are designed in such a way that the configuration related to the environment or deployment-specific settings can easily be stored in a separate file. So these files can be used during the deployment of the Helm chart.

3. Constantly Evolving

We have seen quite a change in Helm since its first 1.0 version launch. Helm charts are updated regularly, and with each update, the management of Kubernetes applications has become easier. Helm 3.0 has actually exceeded the expectations of the DevOps developers as now it does not require developers to connect to the Tiller server for access control.

4. Click Of A Button

Yes, with just a single “click of a button”, a developer can leverage Kubernetes packages. Furthermore, a user can include the dependencies of one Helm chart within another Helm chart, making the system run with similar dependencies without any problem.

5. Kubernetes Functionality

Helm charts are specifically designed for keeping the workload of Kubernetes in check, and they are built on top of Kubernetes to complement the cluster form of architecture used by Kubernetes. When a developer is using Helm for deploying applications on Kubernetes, scalability is the default benefit that a developer enjoys. The Helm workspace stores the data of all the container images that are used by Helm for a particular Kubernetes.

6. Application Testing

Engineers have spent countless hours optimizing Helm charts, and with their deployment on Kubernetes, one can reap what they have sown. The addition of tests is common in many Helm charts. These tests range from proper load testing in your deployment to simpler configuration tests.

Drawbacks Of Helm

There are some drawbacks of Helm charts which a developer might face during its usage, but can be quickly dealt with. Some of the issues with Helm charts are:

  • The Helm chart’s complexity is a significant concern, and it becomes pretty challenging to create and debug complex applications that contain multiple Kubernetes resources.
  • The learning curve of the Helm chart is pretty steep. It does simplify the management of Kubernetes, but creating a Helm chart is not as simple as typing a few commands. The community provides extensive documentation on how to get things done. DevOps developers will still need some time to fully understand its working and implementation.

So this is what Helm is all about. It’s a tool used for managing applications of Kubernetes. We strongly recommend using a Helm chart with the Kubernetes before you move on to create your custom charts. Creating your own chart is going to take a lot of time and requires knowledge of DevOps commands.

Now that you are aware about its benefits, you should try it in your next application. When you are using Helm charts, the deployment can be done in just a few minutes, and if you are well versed in using Helm charts, then deployment takes mere seconds to finish. Helm charts are expected to be used for an increasing number of advanced projects in the future as the community grows.

There are certainly some more benefits which are yet to be discovered.

Thus, Helm charts are going to remain the de facto package for maintaining the Kubernetes clusters for at least a decade or more. Therefore, it’s better to learn its implementation as soon as possible and make your deployment task easy and time-efficient.

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