Helm Interview Questions

Helm is a Kubernetes deployment tool that simplifies the installation and upgrade of applications. The tool supports multiple deployment strategies and enables versioning and rollbacks.

It enables application configuration consistency by encapsulating best practices in chart templates and allowing for easy customization for different environments. Its template engine enables dynamic generation of Kubernetes manifests with conditional logic and parameterization.

What is Helm?

Helm is a tool that simplifies deployment and management of Kubernetes applications. It works like a package manager for software, and automates the process of installing, upgrading, fetching dependencies, and configuring deployments.

It also helps developers and system administrators avoid errors and inconsistencies that can occur when managing complex applications manually. In addition, Helm allows you to roll back to a stable version of an application, if necessary.

It achieves this by combining charts and configurations into a release that is then installed on a cluster. The helm library handles the actual code to perform these tasks, using a client-only architecture that interacts directly with the Kubernetes API server.

What is a Helm chart?

A chart is the package that defines how applications are deployed in Kubernetes. A chart repository is a place where these charts are stored and offered to the community. Some popular repositories are ArtifactHub CNCF’s official repository, Github, and Sysdig’s Helm chart repository.

A helm chart may be accompanied by a provenance file that provides information about its source and what it contains. This is helpful for troubleshooting purposes, notably when a chart is linted with the helm lint command.

Both Kubernetes Operators and Helm charts can be integrated with CI/CD pipelines and GitOps workflows to automate application deployment. However, Kubernetes Operators have a more seamless integration with these features due to their ability to manage custom resources and leverage APIs.

What is a Helm release?

Helm is a tool used to manage the deployment and upgrading of Kubernetes applications. It simplifies application deployment and management in Kubernetes by using charts, which are packaged versions of applications.

The helm tool uses a series of commands to install, upgrade, and rollback Helm releases. It also uses a series of release numbers to track changes and rollbacks.

Security Issues: Storing sensitive information in Helm chart templates and values files can pose a security risk. Avoid this by modularizing charts, following best practices for template optimization, and leveraging CI/CD pipelines for Helm chart builds and testing. Also, use external secret management tools to store sensitive data securely and enable RBAC and least privilege to control access.

What is a Helm subchart?

Helm sub-charts are useful when deploying charts that depend on other charts. For example, the Trivy Operator needs Prometheus to be installed and running in your cluster. To manage chart dependencies, you can source a directory of dependent charts at install time using the helm dependency subcommand.

To understand the key concepts and best practices of Helm, it’s important to get hands-on experience. Set up a Kubernetes cluster (or even just a minikube) and start practicing deploying, updating, and troubleshooting Helm charts. This will give you the confidence to answer technical Helm interview questions about real-world scenarios. In addition, integrating Helm with CI/CD pipelines and deployment processes helps automate the process of testing and deploying Helm releases.

What is a Helm template?

A Helm template is a collection of files that describe a set of Kubernetes resources. Each file contains YAML templates, which can be used to describe a specific resource or application. Helm uses these templates to simplify the deployment of Kubernetes applications.

It is important to follow best practices when using Helm. This includes using clear release notes, implementing CI/CD pipelines for Helm releases, and ensuring that sensitive information is handled securely.

It is also a good idea to use linting tools to validate Helm templates, and ensure that the indentation of template code follows standard conventions. This will help to reduce the risk of errors and security breaches.

What is a Helm install?

A Helm install is a set of charts and configurations that are deployed to a Kubernetes cluster. Helm can install, upgrade, and uninstall charts as well as configure and manage them.

A chart may contain conditional logic such as if, else, or with statements. These can make the chart more flexible and dynamic. Using semantic versioning in the chart can help you manage dependencies and ensure compatibility between different versions of your application.

Helm is most useful when managing complex applications with many microservices. Here are some signs that your project could benefit from Helm:

What is a Helm upgrade?

A Helm upgrade is the process of updating a chart and its dependencies in a Kubernetes cluster. The chart may be upgraded to a newer version of itself or to another chart that is compatible with the current product.

A release has a unique name, a version number, and a tag. Its version number increments with each helm install, upgrade, or rollback. The helm install, upgrade, and rollback commands have options that enable you to customize their behavior.

The Helm project’s official topics guide has detailed descriptions of the available cli flags for installing, upgrading, and rolling back Helm releases. The helm upgrade command also supports options that minimize downtime during the upgrade process.

What is a Helm rollback?

A Helm rollback is a way to revert a Helm release to a previous state, effectively undoing an upgrade. Helm uses Semantic Versioning (SemVer) to manage chart versions and store their configuration, ensuring that a release can be rolled back to any previously configured version.

Helm also provides a UI to view all installed releases and their revision histories. To use the helm rollback feature, select the release name and revision number, then click Rollback.

Implementing a rollback strategy with Helm is an important part of any deployment pipeline. Combine this with other best practices, such as testing in controlled environments and maintaining documentation, to ensure that your applications are resilient and reliable.