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Do you need help managing complex applications on Kubernetes? Say hello to Helm, the package manager that simplifies the deployment process. In this exciting blog post, we'll uncover what Helm is, how it works, and why it's a game-changer for Kubernetes developers.
If you're a developer or operator working with Kubernetes, you know that managing complex applications can be a daunting task. That's where Helm comes in.
Helm is a package manager for Kubernetes that simplifies the deployment and management of applications, making your job easier.
In this blog post, we'll dive deep into what Helm is. We will also discuss how it works and why it's an indispensable tool for any Kubernetes user. Whether you're a seasoned pro or just starting, you'll find valuable insights into Helm and its capabilities.
So, let's explore the exciting world of Helm in Kubernetes!
What is Helm in Kubernetes (K8s)?
Helm is a package manager for Kubernetes that enables developers and operators to package, deploy, and manage applications as Kubernetes resources.
Helm comprises two main components: Helm Charts, packages of pre-configured Kubernetes resources, and the Helm CLI, which allows users to manage and install these charts.
With Helm, developers can easily version and deploy their applications consistently, while operators can simplify deploying and updating applications.
Helm also supports templating. This allows for easy customization of resources and includes a rich ecosystem of third-party charts that can be easily installed and customized.
Also Read: How to Create & Manage Kubernetes Clusters using Kubeadm?
What is a Helm Chart?
Helm Chart is a package of pre-configured Kubernetes resources that simplifies deploying and managing applications on Kubernetes.
In this section, we'll explore the key components of a Helm Chart and walk you through the process of creating one.
A Helm Chart is a collection of YAML files that define Kubernetes resources, such as deployments, services, and config maps.
A Chart also includes a Chart.yaml file, which provides metadata about the Chart and values.yaml file allows users to customize the Chart for their specific use case.
How to Create a Helm Chart?
Now let's quickly see how you can create your own Helm chart. Creating a Helm Chart involves a few steps, let's look at them.
Initialize a Chart
Use the Helm CLI to create a new Helm Chart structure. Open your terminal and run the following command:
helm create <chart_name>
Replace <chart_name> with the desired name for your chart. This command will generate a basic Helm Chart structure with some default files and directories.
Customize the Chart
Inside the created chart directory, you'll find various files, including Chart.yaml, values.yaml, and templates. Customize these files to match the specifications of your application and its Kubernetes resources.
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Chart.yaml: This file contains metadata about your chart, such as version, description, and maintainer information. -
values.yaml: This file defines the default values for your application's configurations. Users can override these values during installation. -
templates: This directory holds the Kubernetes manifest files (in YAML format) that define the resources for your application, like Deployments, Services, ConfigMaps, etc. Use Go templates for dynamic content in these files. -
charts: Directory containing dependencies to other Helm Charts if required.
Package the Chart
Once you've defined your Helm Chart, you can package it into a distributable archive.
In the chart's root directory, run:
helm package .
This will create a .tgz file representing your packaged Helm Chart.
Distribute and Install
Share the packaged chart with others or deploy it to Kubernetes. To install the chart on a Kubernetes cluster, use the Helm CLI:
helm install <release_name> <chart_path>
Replace <release_name> with a name for your release, and <chart_path> with the path to your packaged chart .tgz file or the chart directory.
What is a Helm Template?
Helm Template is a powerful tool that allows users to customize and render Helm Charts before deploying them on Kubernetes.
With Helm Template, users can preview the resources created by a Chart and customize them with values from a YAML file without actually installing the Chart.
Helm Template uses Go's template language to dynamically generate YAML files based on user-defined values. It allows users to override any part of a Chart's resources, such as the number of replicas, image tags, and environment variables.
This all is possible without modifying the Chart itself.
Helm Template also supports conditional statements, loops, and functions, making it a powerful tool for generating complex Kubernetes resources.
Brief into Helm Architecture
Helm is built on a modular architecture that comprises two main components: the Helm CLI and Helm Charts.
The Helm CLI is a command-line interface built on Kubernetes' client-go library. It enables users to interact with the Kubernetes API server and install, upgrade, and manage Helm Charts.
On the other hand, Helm Charts are packages of pre-configured Kubernetes resources that define how an application should be deployed.
They contain YAML files that describe Kubernetes resources like deployments, services, and config maps, as well as metadata files that describe the Chart and its dependencies.
One of the most significant features of Helm Charts is their support for templating. With the help of the Go templating language, users can customize Kubernetes resources using values from YAML files.
This makes customizing resources like image tags and environment variables easier.
In summary, Helm's architecture is designed to simplify managing and deploying applications on Kubernetes.
The Helm CLI and Helm Charts work together seamlessly to provide users with a powerful tool streamlining the application deployment workflow.
How does Helm Work with Kubernetes?
At a high level, Helm works by defining and deploying Kubernetes resources using Helm Charts. A Helm Chart is a package of pre-configured Kubernetes resources that define how an application should be deployed on a Kubernetes cluster.
Helm Charts are built using YAML files that define Kubernetes resources like deployments, services, config maps, and metadata files that describe the Chart and its dependencies.
To install a Helm Chart, a user runs a Helm command that deploys the Chart to the Kubernetes cluster.
Helm will then create the Kubernetes resources defined in the Chart, making it easy to deploy and manage complex applications on Kubernetes.
Helm also simplifies the process of upgrading and rolling back applications on Kubernetes.
Users can use the Helm CLI to upgrade a Chart to a new version, and Helm will handle updating the Kubernetes resources and rolling out the new version of the application.
Also Read: Top 20+ Kubernetes Best Practices
What is Helm Used for?
Helm is a versatile tool that can be used for a variety of purposes, including:
Simplifying Application Deployment
Helm makes deploying complex applications with multiple dependencies easy using pre-built Helm Charts.
This allows developers and operators to focus on building and maintaining the application instead of spending time on the deployment process.
Managing Kubernetes Manifests
Helm Charts are built using YAML files that define Kubernetes resources, making it easy to manage Kubernetes manifests.
With Helm, users can apply changes to the manifests, track different versions of an application, and roll back to a previous version if necessary.
Collaborating between Development and Operations Teams
Helm Charts allow developers to package and share applications with operations teams, facilitating collaboration between different teams.
This makes deploying and managing applications on a Kubernetes cluster easier, streamlining the entire development process.
Scaling Applications
Helm makes it easy to scale applications on a Kubernetes cluster. It allows users to quickly add or remove resources, making managing the resources needed for an application easy.
When to Use Helm?
Here are some scenarios where Helm can be particularly useful:
Deploying Complex Applications
Helm can simplify the process if you're deploying an application with multiple dependencies or complex configurations. Helm Charts allow you to package all the necessary resources for your application and deploy them in one simple command.
Maintaining Consistency Across Environments
Helm Charts can help ensure your applications are consistently deployed across different environments.
Using the same Chart for all environments ensures that the same resources are being deployed with the same configuration.
Streamlining Collaboration Between Teams
Helm Charts can package and share applications with operations teams, streamlining collaboration between development and operations teams.
Using the same Chart allows everyone involved in the deployment process to be on the same page.
Simplifying Application Versioning
Helm Charts make it easy to version and roll back applications, allowing you to easily track changes and revert to previous versions if necessary.
This can be particularly useful when testing new features or changes to an application.
Also Read: Kubernetes Cost Optimization Tools
When Not to Use Helm?
While Helm is a powerful tool for deploying and managing applications on a Kubernetes cluster, there are some scenarios where it may not be the best choice.
Here are some situations where you may want to consider using an alternative tool:
Simple Deployments
Helm may be overkill if you're deploying a simple application with few dependencies. In this case, using kubectl to deploy the application may be more appropriate.
Security Considerations
Helm relies on a centralized repository for Charts, which can introduce security risks.
If you're deploying sensitive applications or dealing with sensitive data, you may consider using an alternative tool that doesn't rely on a centralized repository.
Limited Control over Deployment Process
While Helm can simplify the deployment process, it may not be suitable if you need more control over the deployment process.
If you need to customize every aspect of the deployment process, you may want to consider using alternative tools that allow more fine-grained control.
Limited Support for Non-Kubernetes Environments
While Helm is designed specifically for Kubernetes, it may not be the best choice if you need to deploy applications to non-Kubernetes environments.
In this case, a more generic deployment tool may be more appropriate.
How to Use Helm for Rollbacks and Deployments?
When using Helm for deployments, it's essential to understand how to use it for rollbacks and deployments. Helm maintains a version history of all configurations that have been sent over to Kubernetes.
Users can roll back to the last known working configuration if an upgrade doesn't work as expected.
To roll back to the previous configuration, they should simply run the command:
helm rollback MyApp <version>
Here, <version> is the specific version of the release that the user wants to roll back to.
Helm will then update the configuration in Kubernetes to match the previous version, ensuring that the deployment is reverted to its previous state.
Furthermore, when upgrading the application using Helm, users can use the --wait for the flag to wait until all resources are up to date before completing the upgrade.
This is particularly useful when upgrading large applications with many dependencies.
To upgrade an application using Helm with the --wait for the flag, users can run the command:
helm upgrade MyApp <chart> --wait
This ensures that all resources are updated, and the application is deployed successfully with the new configuration.
Also Read: Kubernetes vs HashiCorp Nomad
Helm Chart Example
To deploy the helm chart, run the command below:
helm install --name sample-chart
Helm vs Kustomize
Helm is a package manager for Kubernetes, while Kustomize is a tool for customizing Kubernetes configurations. Helm provides a more comprehensive solution for deploying applications, while Kustomize is ideal for making targeted changes to existing deployments.
Also read: Terraform Cheat Sheet - A List of Most Common Terraform Commands
Helm vs Terraform
Helm simplifies Kubernetes deployments as a package manager, allowing you to easily install, upgrade, and manage applications. In contrast, Terraform is a tool for infrastructure as code. It is used for provisioning infrastructure resources.
Helm vs Kubectl
Helm is a package manager, and Kubectl is a CLI. Helm manages releases, and Kubectl manages resources.
Also Read: Kubectl Cheat Sheet
Helm vs Docker Compose
Helm is a package manager for Kubernetes, while Docker Compose is a tool for defining and running multi-container Docker applications. Helm is designed specifically for Kubernetes, while Docker Compose is more of a general container orchestration tool.
Helm vs YAML
Helm is a package manager, while YAML is a language for defining configurations. Helm provides a templating engine and release management capabilities, whereas YAML does not.
Helm can also manage to deploy multiple Kubernetes objects with a single command, while YAML requires separate files for each object.
Helm vs Ivy
Ivy is a build system for Angular projects, while Helm is a package manager for Kubernetes. They serve completely different purposes and cannot be compared directly.
Helm vs ArgoCD
Helm is a package manager for Kubernetes, while ArgoCD is a continuous delivery tool for Kubernetes. Helm is used for packaging and deploying applications, while ArgoCD is used for the continuous delivery of applications.
Also Read: Kubernetes vs Docker Swarm
Frequently Asked Questions
Can we use Kubernetes without Helm?
Yes, Kubernetes can be used without Helm. Helm is an optional tool that can help manage Kubernetes applications and configurations, but it is not a requirement for using Kubernetes.
What is Helm and YAML?
A Helm Chart allows you to automate the execution of YAML template files & manifests in an order you define.
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