Helm is a package manager for Kubernetes, similar to yum for Linux or npm for Node.js. Charts deployed by Helm are complete, packaged Kubernetes applications. They include versioned, pre-configured application resources that can be deployed as a single unit. You can deploy different versions of the chart with different sets of configurations.
Helm is an important part of a well-designed Kubernetes architecture. It can significantly improve the Kubernetes development experience, by improving productivity, making Kubernetes applications less complex, and making it easier to manage cloud native and microservices applications.
In this article, you will learn:
Kubernetes isn’t easy to learn and use, especially for those new to containerized environments. Kubernetes Helm can make Kubernetes much easier to use by:
As of Helm 3, Helm is a client-only system: the client is known as helm, it interacts directly with the Kubernetes API server. The old Helm server-side component, known as Tiller, has been removed.
Here are the main components of Kubernetes Helm is a bit more detail:
The following best practices can help you use Helm more effectively.
Helm charts have two types of versions—the chart version (version field in Chart.yaml) and the version of the application deployed by the chart (appVersion field in Chart.yaml). The two are totally independent and can be synced or separated. However, it is recommended to maintain consistency in your versioning strategy across all charts.
A considerable advantage of Helm charts is the ability to consolidate multiple operational components, which have a common denominator, into a single chart. Avoid placing a single chart in each repository from which you intend to deploy. Instead, invest in having a central set of charts that can serve the entire organization.
This makes it easy to administer standardized health checks, and maintain common configurations across the organization. And, as an added benefit, you can update Kubernetes resource API versions from a central location.
To facilitate using a central set of Helm charts for the entire organization, ensure charts are created by experienced Kubernetes professionals, who can plan them for consistent use across multiple use cases. Ensure they are built with proper error handling, consistent labeling, and correct YAML indentation.
Helm is more than just a template engine. It is a package manager that also includes template functionality. It is possible to only use Helm to create a generic Kubernetes manifest, and install it on your cluster using kubectl, but this misses the true power of the platform. Helm truly shines when you use it as an end-to-end package manager, and use it not only to create manifests but also to actually install applications on your cluster.
If you are using the Helm CLI, make sure that only Helm can change values in Kubernetes manifest. For example, don't modify deployment replicas directly—use Helm to change the values.
You may be familiar with kubectl apply, which is an easy way to deploy resources to your Kubernetes environment. However, you should not use kubectl for Helm-deployed environments, as this can cause problems the next time you run Helm commands. To change your environment, modify values in your Helm chart and use Helm to redeploy.
To further reduce the complexities of Kubernetes environments, Spot Ocean automates infrastructure management. Users can leverage the Spot Helm chart to deploy the Ocean toolkit, which will install the Spot Kubernetes controller and operators, as well as a metrics-server. These components are core to Ocean’s serverless engine and delivering:
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