Everything You Need to Know About Helm

Introduction

Helm is essential for simplifying application deployment and management within a Kubernetes cluster. It serves as a package manager for Kubernetes, like how apt or yum work on OS systems such as Ubuntu and Red Hat. Helm allows developers and administrators to easily package, configure, and deploy applications and services in Kubernetes clusters.
In this detailed introduction, we will look at the essential parts of Helm, such as its tasks, components, installation, and usage. In addition, we will walk through the process of deploying a LAMP stack in a Kubernetes cluster with a Helm chart.

Helm is the foundation of effective Kubernetes application deployment, offering a single, package-manager-like approach for handling complicated container orchestration systems. Helm charts enable developers to encapsulate the complete application stack into reusable packages, including dependencies, configurations, and Kubernetes resources. This streamlined technique speeds up the deployment process and reduces errors by allowing for simple versioning, changes, and rollbacks. Helm’s ability to standardize application management across clusters and environments makes it a must-have solution for any team trying to boost productivity and maintain consistency in their Kubernetes projects.

Helm Tasks

Helm is responsible for various critical activities in a Kubernetes environment, including:

• Obtaining apps and software packages from repositories.
• Installing apps and packages on the Kubernetes cluster.
• Automatically install app requirements.
• Upgrade apps and dependencies as needed.

Helm Components

Helm’s functionality is provided by many essential components that work together to manage Kubernetes applications:

• Helm CLI: The command-line interface is how developers and administrators interact with Helm. It enables users to run commands for installing, upgrading, managing, and troubleshooting apps in Kubernetes clusters.
• Charts: Helm charts are the primary packaging format for Kubernetes apps and resources. Charts contain YAML configuration files and templates that explain how to deploy apps. They encapsulate Kubernetes items like deployments, services, secrets, and persistent volumes, allowing you to manage the whole application lifecycle easily.
• Chart Repositories: These are collections of charts stored on distant servers, similar to package repositories in standard operating systems. Users can look up, download, and install charts from these repositories, including official and community-maintained sources.
• Releases: A release is a specific Helm chart deployed in a Kubernetes cluster. Multiple releases of the same chart can coexist in the same cluster, allowing for simultaneous versioning and managing an application’s various settings.
• Values Files: Helm allows you to customize chart values using values files (usually known as values.yaml), which specify configuration options. These files allow users to customize the chart’s distribution based on their requirements.
• Templates in a Helm chart specify how resources in Kubernetes should be rendered and produced. The templating engine allows for dynamic resource configuration based on input values, making it simple to adapt charts to various environments and use cases.

By combining these components, Helm provides a comprehensive and versatile solution for packaging, deploying, and administering Kubernetes applications, allowing users to perform complicated orchestration tasks efficiently.

Helm Charts

• Helm charts are the foundation of Helm’s ability to automate Kubernetes application deployment and administration.
• These charts package the whole application stack into reusable packages, including Kubernetes resources and configurations.
• Charts enable developers to construct consistent, portable deployments that facilitate growing and updating programs across several settings.
• One of the distinguishing features of Helm charts is their ability to accommodate a wide range of deployment situations via a flexible template system. This approach allows for dynamic configuration of Kubernetes resources based on input values, allowing deployments to be tailored to unique use cases or settings without editing the chart itself.
• In addition, Helm charts can be shared via chart repositories, allowing developers to use community-contributed packages for a wide range of applications and services. This ecosystem promotes knowledge exchange while also accelerating application development and deployment in Kubernetes.

A Helm chart’s core structure consists of a predefined set of files and directories organized in a standardized manner. This style promotes consistency and organization among charts, making it easier for developers to comprehend and alter them. Here is an overview of the typical directory structure of a Helm chart:

• /: The root directory of the chart, usually named after the software or application being deployed.
• Charts/: A directory to manage chart dependencies. This section contains sub-charts or other charts on which the main chart is based. However, requirements are more commonly used. A yaml file is used to specify dependencies.
• The crds/ directory contains custom resource definitions (CRDs) utilized by the chart. If the chart has custom resources, the definitions should be stored in this directory.
• The templates/ directory provides YAML templates for Kubernetes resources generated by the chart. Templates can be rendered dynamically using values from the values.yaml file.
• chart.yaml is a metadata file that contains information about the chart, including its name, version, maintainer information, and description.
• LICENCE (Optional) A text file providing the chart’s license information.
  md (optional): A readme file that contains important information for chart users.
• Requirements.yaml is a file that lists the chart’s dependencies, such as other charts and external resources.
• values. yaml: This file contains the chart’s default setup values. Users can alter these values during installation to customize the chart’s deployment.

Helm Installation

Helm is available on Linux, Windows, and macOS. It can be installed in two main ways:

1. From The Helm Project: Use binary releases or scripts.
2. Using Package Managers: Examples include apt for Ubuntu, Chocolatey for Windows, and Homebrew for macOS.

Helm Commands

Helm offers a variety of commands to manage applications in Kubernetes:

Deploying a LAMP Stack in Kubernetes Using Helm Charts

Deploying apps to Kubernetes can be difficult because of the number of components required, such as containers, services, secrets, and configurations. Helm addresses this deployment complexity by packaging Kubernetes apps and their dependencies, which include additional containers, services, secrets, and ConfigMaps.

Why Helm Charts?

Helm charts serve as package managers for Kubernetes apps, making it easier to deploy, manage, and update them. Charts can be published in repositories and then used to install applications in any Kubernetes cluster.

Traditional LAMP Stack Deployment

Traditionally, implementing a LAMP stack in a Kubernetes cluster required managing numerous Apache, MySQL, and PHP deployments, as well as configuring secrets, storage volumes, and ConfigMaps. This method necessitates manual editing of manifest files and can result in mistakes owing to frequent changes across many clusters.

LAMP Stack Deployment Using Helm Charts

Because the LAMP stack is so widespread, users can search for charts in a public repository like Artifacthub.io and install them immediately. Here’s how to deploy a LAMP setup with Helm charts.

1. 1. Searching for Helm Charts                        To find Helm charts, use the search command in the CLI. For example, when searching for an Apache chart:        Helm search hub Apache
2. Installing Helm charts.                   After you’ve found the necessary charts, use the commands below to install them. In this example, we will use Bitnami’s certified charts to supply Apache and MySQL within the cluster.  helm repo add bitnami https://charts.bitnami.com/bitnami helm install k8s-apache --set imagePullPolicy=Always bitnami/apachehelm install k8s-mysql --set auth.rootPassword=testpassword123, auth.database=lamp_database bitnami/mysql
3. Verifying Installation   To confirm that the necessary resources have been created in your cluster, run the following command: kubectl get all
4. Uninstalling Charts       To uninstall the charts and programs from the cluster, execute the following commands: helm uninstall k8s-apache k8s-mysql

And that’s it! You have successfully created a LAMP stack in Kubernetes using a single Helm chart.

Conclusion

Helm is a robust tool for automating application deployment and administration in Kubernetes clusters. Helm charts simplify the process of deploying, managing, and updating applications, making them an indispensable tool for any Kubernetes project.

About CloudThat

Established in 2012, CloudThat is a leading Cloud Training and Cloud Consulting services provider in India, USA, Asia, Europe, and Africa. Being a pioneer in the cloud domain, CloudThat has special expertise in catering to mid-market and enterprise clients from all the major cloud service providers like AWS, Microsoft, GCP, VMware, Databricks, HP, and more. Uniquely positioned to be a single source for both training and consulting for cloud technologies like Cloud Migration, Data Platforms, DevOps, IoT, and the latest technologies like AI/ML, it is a top-tier partner with AWS and Microsoft, winning more than 8 awards combined in 11 years. Recently, it was recognized as the ‘Think Big’ partner from AWS and won the Microsoft Superstars FY 2023 award in Asia & India. Leveraging its position as a leader in the market, CloudThat has trained 650k+ professionals in 500+ cloud certifications and delivered 300+ consulting projects for 100+ corporates in 28+ countries.