What Is Helm Charts in Cloud Computing?
Also known as: Helm Charts, Kubernetes package manager, CNCF Helm, KCNA exam, helm install
On This Page
Quick Definition
Helm Charts are like app store packages for Kubernetes. They bundle all the YAML configuration files needed to run an application, so you do not have to write each one from scratch. With Helm, you can install an entire application simply by running one command, and you can also update or remove it just as easily.
Must Know for Exams
The CNCF Kubernetes and Cloud Native Associate (KCNA) exam includes Helm Charts as a key topic under the Kubernetes Fundamentals domain. The exam expects you to understand the role of Helm as a package manager and its basic commands and concepts. Specifically, the exam objectives mention package management with Helm, including installing, upgrading, and rolling back applications.
You may be asked about the differences between Helm 2 and Helm 3, particularly the removal of Tiller and the security implications. The exam also tests your understanding of chart structure: what are the main components of a Helm Chart (Chart.yaml, values.
yaml, templates/), and what is the purpose of each. Another common area is the release management concept: what a release is and how Helm tracks releases. You might also see questions about Helm repositories: how to add a repository, search for charts, and install a chart from a repository.
The exam does not require deep hands-on YAML coding, but you should be able to interpret basic chart templates and understand how values are injected. Multiple-choice questions may present a scenario where an administrator needs to deploy an application with custom parameters, and you must choose the correct helm command or identify what a command does. For example, you could see a question like: Which command installs a chart named mychart from the current directory?
Answer: helm install myrelease . Questions about rollbacks are also common, such as: After a failed upgrade, which command reverts to a previous version? Answer: helm rollback myrelease 1.
The KCNA exam also emphasizes troubleshooting concepts. You might be asked what to check if a Helm install fails (e.g., invalid template, missing values, incorrect API version). Understanding dependency management, though less likely, could appear in an advanced question.
In summary, for the KCNA exam, focus on the lifecycle commands, chart structure, and the difference between Helm 2 and 3. Do not neglect the practical scenarios that require you to choose between similar commands like install and upgrade.
Simple Meaning
Imagine you want to set up a new smart home system. You have to buy a hub, connect light bulbs, install sensors, configure the Wi-Fi, and set up the app on your phone. Doing this piece by piece for every room would take forever.
Now imagine instead you could buy a single box called a Smart Home Kit. That kit contains everything you need for one room: the hub, the bulbs, the sensors, and a simple instruction booklet. You just open the box, follow the instructions, and the room is done.
If you later want to add motion detectors, you get an upgrade kit. That is what Helm Charts do for Kubernetes. Kubernetes is a system for running containerized applications, and each part of an application (like a web server, a database, a load balancer) is defined in a separate YAML file.
Writing and managing all these files by hand is tedious and error prone. A Helm Chart packages all these files together into a single, reusable bundle. It also includes a way to change settings (like the number of servers or the database password) without editing the original files.
This makes it much faster to deploy, update, and remove applications. Just as a smart home kit saves you from wiring every device individually, a Helm Chart saves you from writing dozens of YAML files. You can share charts with your team or get pre-made charts from the community, just like downloading apps from a store.
Helm also tracks what you have installed, so you can roll back to a previous version if something goes wrong. For beginners, the key idea is that Helm takes the mess of configuration files and turns it into a neat, reusable package that you can manage with simple commands.
Full Technical Definition
Helm is a package manager for Kubernetes, analogous to apt for Debian or yum for CentOS. It operates as a client-server system. The client is the helm CLI, and the server component is Tiller (deprecated as of Helm 3) or, in modern Helm 3, a client-only architecture that communicates directly with the Kubernetes API server using the user's kubeconfig credentials.
A Helm Chart is a collection of files organized in a specific directory structure. The core of a chart is the Chart.yaml file, which contains metadata such as the chart name, version, description, and dependencies.
The templates/ directory holds Go template files that, when rendered, produce valid Kubernetes YAML manifests for resources like Deployments, Services, ConfigMaps, and Ingresses. The values.yaml file contains default configuration values that are injected into the templates.
Users can override these values with custom YAML files or command-line flags at install or upgrade time, enabling environment-specific deployments without altering the chart itself. The dependency management system allows a chart to depend on other charts, which are fetched and installed automatically. This is declared in the Chart.
yaml file under the dependencies field and resolved using helm dependency update. Helm uses a release-based management system. Each installation of a chart creates a named release, and Helm tracks the state of all releases in the cluster (stored in Secrets in the kube-system namespace by default).
This enables rollbacks, upgrades, and deletion. The helm install, helm upgrade, helm rollback, and helm uninstall commands manage the lifecycle of releases. The rendering process involves several steps.
Helm reads the chart, parses the Chart.yaml and values.yaml, then processes the template files using the Go template engine. The resulting YAML is validated against the Kubernetes API schemas before being sent to the cluster via kubectl apply semantics.
Helm Charts are published in repositories, which are simple HTTP servers or Helm OCI registries. The public Helm Hub (now Artifact Hub) aggregates chart repositories for discovery. The CNCF (Cloud Native Computing Foundation) governs Helm as a graduated project, ensuring its stability and community support.
For the KCNA exam, understanding the concepts of charts, releases, repositories, and the helm install/upgrade/rollback workflow is essential. The exam may also test the difference between Helm 2 (with Tiller) and Helm 3 (client-only, with improved security via RBAC).
Real-Life Example
Think of Helm Charts like a recipe box for a professional kitchen. You are a chef who wants to create a three-course meal: a starter, a main course, and a dessert. Each dish requires multiple ingredients, specific cooking times, and precise plating instructions.
If you had to write out every recipe from scratch each time, you would waste a lot of time and risk making mistakes. Instead, you have a recipe box. Each recipe card lists all the ingredients, the steps, and the required cookware.
When you want to cook a dish, you pull out the card, follow it, and the meal comes together. Over time, you might tweak the card by writing notes (like substitute gluten-free flour or double the sauce). That recipe card is a Helm Chart.
The ingredients and steps are the YAML templates. The cookware is the Kubernetes cluster. The notes you write on the card are the values you override for different occasions. For example, when cooking for a large party, you might double the quantities.
That is like setting the replicas value in your values.yaml to scale up the number of pods. You can also combine multiple recipe cards to create a full menu. This is like Helm Chart dependencies, where one chart depends on another (e.
g., an application chart depends on a PostgreSQL chart). You keep your recipe box organized by meal type or cuisine, just like Helm repositories organize charts by purpose. If a recipe fails, you can go back to a previous version by checking your earlier notes.
That is the rollback feature. The recipe box does not tell you how to light the stove or chop an onion; it assumes you already know the basics of cooking. Similarly, Helm assumes you have a working Kubernetes cluster and basic knowledge of containers.
Ultimately, the recipe box saves you time, reduces errors, and lets you share your delicious meals with other chefs. Helm Charts do the same for Kubernetes applications: they package, share, and manage complex deployments with simplicity and consistency.
Why This Term Matters
In real IT work, managing Kubernetes applications manually by writing and applying dozens of YAML files is not only tedious but also highly error prone. A single typo in a YAML file can cause an application to fail to deploy or behave unpredictably. Helm Charts address this by providing a standardized, repeatable way to define, package, and deploy applications.
This matters because organizations that run Kubernetes in production often have multiple environments (development, staging, production) with slight differences in configuration. Without Helm, you would have to maintain separate YAML files for each environment, leading to drift and inconsistency. With Helm, you maintain one chart and use different values files for each environment.
This reduces configuration drift and makes deployments predictable. Helm also enables automated CI/CD pipelines. Tools like Jenkins, GitLab CI, and ArgoCD can run helm upgrade commands as part of a pipeline, ensuring that the latest version of an application is always deployed to the cluster.
This is critical for DevOps practices and continuous delivery. Another practical benefit is dependency management. Many applications rely on external services like databases, message queues, or monitoring tools.
Helm Charts can declare these dependencies and install them automatically, saving hours of manual setup. For operations teams, the ability to roll back a failed release with a single command (helm rollback) is invaluable during incidents. In a fast-paced production environment, downtime costs money, and quick recovery is essential.
Helm also enforces best practices by encouraging users to separate configuration from code (via values.yaml) and to version their charts. Finally, because Helm is a CNCF graduated project, it has a large ecosystem.
There are thousands of pre-built charts available on Artifact Hub for common tools like Nginx, Prometheus, Grafana, and Elasticsearch. This means you do not have to reinvent the wheel. For infrastructure engineers, site reliability engineers, and platform teams, Helm is not just a convenience; it is a fundamental tool for managing cloud native applications at scale.
How It Appears in Exam Questions
In the KCNA exam, Helm-related questions appear in several patterns. One common pattern is the command-line knowledge question. For example: A developer wants to install a Helm chart named nginx from the official repository.
Which command should they use? The answer involves helm repo add, helm repo update, and helm install. Another pattern is the concept question. The exam may ask: What is the primary purpose of Helm in a Kubernetes environment?
The correct answer would be to manage packaging, deployment, and lifecycle of applications. Scenario questions are also frequent. For instance: An operations team has deployed an application using Helm.
After applying a new upgrade, the application becomes unresponsive. The team needs to quickly restore the previous working version. Which Helm command should they use? This tests the understanding of helm rollback.
You might also see questions about chart structure, such as: Which file in a Helm Chart contains default configuration values that can be overridden during installation? The answer is values.yaml.
Another type is the comparison question, often contrasting Helm 2 and Helm 3. For example: What is a key security improvement in Helm 3 compared to Helm 2? The answer is the removal of Tiller, which required cluster-wide permissions.
There could be troubleshooting questions: A user runs helm install myapp ./mychart but receives an error indicating that a required value is missing. What should the user do? The correct response is to provide the missing value using the --set flag or a custom values file.
Questions about release management also appear. For example: When a chart is installed, what is created to track the deployment? The answer is a release. A more nuanced question might ask: Which command lists all releases in the cluster?
Answer: helm list. Finally, the exam sometimes includes questions about dependencies. For instance: An application chart depends on a PostgreSQL chart. Where should this dependency be declared?
In the Chart.yaml file under the dependencies section. By understanding these question patterns, you can prepare to answer confidently. Focus on mastering the helm command syntax and the conceptual roles of each chart component.
Study cncf-kcna
Test your understanding with exam-style practice questions.
Example Scenario
Imagine you are a cloud engineer at a small startup. Your team has developed a Node.js web application that needs to run on a Kubernetes cluster. The application consists of three parts: a web server, a Redis cache, and a PostgreSQL database.
Setting this up manually means creating separate YAML files for a Deployment (for the web server), a Service, a ConfigMap for environment variables, a PersistentVolumeClaim for the database, and Secrets for passwords. That is at least six files. If you need to deploy to a staging environment with different resource limits and a different database password, you have to duplicate and modify all these files.
This is error-prone and time-consuming. Instead, you decide to use a Helm Chart. You create a chart called myapp. In the templates/ directory, you put all the YAML templates with placeholders for values like image tag, replica count, and database URL.
In values.yaml, you set defaults. For the staging deployment, you create a staging-values.yaml file that overrides the database password and resource limits. Now, deploying to staging is as simple as running: helm install myapp-staging .
/myapp -f staging-values.yaml. A few weeks later, your team updates the web server to version 1.2. You run helm upgrade myapp-staging ./myapp -f staging-values.yaml --set image.tag=1.
2. If the update causes issues, you can instantly roll back with helm rollback myapp-staging 1. This scenario shows how Helm simplifies multi-environment deployments, reduces human error, and gives you control over application lifecycle.
Without Helm, you would be managing multiple copies of YAML files, increasing the risk of misconfiguration and slowing down your release cycle.
Common Mistakes
Believing that Helm Charts are only for simple applications and cannot handle complex stateful workloads.
Helm Charts can handle complex applications, including stateful sets, operators, and custom resource definitions. Many production-grade charts for databases like PostgreSQL and Cassandra exist.
Always check the chart's documentation and capabilities. Helm is designed to manage applications of any complexity, as long as the chart is well authored.
Thinking that helm install and helm upgrade are always interchangeable.
helm install creates a new release, while helm upgrade modifies an existing release. Using helm install on an already installed release will fail with a conflict error.
Use helm install for first-time deployments and helm upgrade for updates. Use helm status to check if a release already exists before deciding which command to run.
Assuming that Helm templates are just static YAML files and cannot include logic.
Helm templates are Go templates that support conditionals, loops, functions, and variable manipulation. They can generate dynamic YAML based on values and built-in objects.
Study the Helm template language basics. Understand how to use if/else, range, and functions like required and coalesce to create flexible templates.
Overlooking the security implications of using Tiller in Helm 2 in a production environment.
Tiller runs inside the cluster with elevated permissions, potentially allowing any user with helm client access to deploy or modify resources beyond their intended RBAC scope.
Use Helm 3, which removes Tiller and uses the user's kubeconfig credentials, enforcing RBAC at the user level. If you must use Helm 2, secure Tiller with service accounts and limited permissions.
Forgetting to run helm dependency update before installing a chart that has dependencies.
If dependencies are not downloaded and stored in the charts/ directory, the install command will fail or miss required sub-charts.
Always run helm dependency update before helm install for charts with dependencies. This fetches the referenced charts from the repositories.
Confusing chart version with app version.
The chart version (in Chart.yaml) refers to the version of the chart package itself, while app version refers to the version of the application being deployed. They are independent.
When upgrading, focus on the chart version if changing configuration, and update app version separately in values. Use helm show chart to inspect both.
Exam Trap — Don't Get Fooled
A question asks: What command should you use to update an existing Helm release to a new version of the chart? The options include helm install, helm upgrade, and helm update. Many learners choose helm install because they associate 'install' with 'deploying'.
In the context of an existing release, helm install will fail. Remember that Helm has two distinct commands: helm install for first-time deployment, and helm upgrade for subsequent updates. Think of a release as a named object; you can only have one release with a given name.
If it already exists, you must upgrade it. A mnemonic: 'Install once, upgrade always afterwards.'
Commonly Confused With
A Helm Chart is a package of static YAML templates that deploys an application. A Kubernetes Operator, on the other hand, is a custom controller that automates the lifecycle of an application, including scaling, backups, and recovery, using custom resource definitions. Operators are more dynamic and do not just deploy; they manage ongoing operations.
A Helm Chart for MySQL installs the database once. An Operator for MySQL can automate taking backups, handling failover, and resizing storage continuously.
Kustomize is a configuration management tool that patches and overlays YAML files without using templates or a packaging system. Helm Charts are packaged, versioned, and include a template engine with values injection. Kustomize is simpler and does not manage releases or rollbacks.
You use Kustomize to apply different environment overlays to your raw YAML files. You use Helm to install a complete packaged application with dependencies, then later upgrade or roll back it as a unit.
Docker Compose is a tool for defining and running multi-container applications on a single host using a docker-compose.yml file. Helm Charts are for deploying applications on a Kubernetes cluster across multiple nodes. Compose does not handle cluster-level concepts like services, ingress, or persistent volumes in the same way.
Docker Compose runs your web app and database on your laptop. Helm deploys the same app across 10 nodes in a production Kubernetes cluster with load balancing and auto-healing.
kubectl apply -f directly applies individual YAML files to the cluster. Helm Charts group multiple YAML files, support templating, and manage releases. kubectl apply does not provide package management, version tracking, or rollback capabilities.
You use kubectl apply -f deployment.yaml to deploy one resource. You use helm install myapp ./mychart to deploy an entire application stack with database, web server, and load balancer, all while tracking the release for future rollbacks.
Step-by-Step Breakdown
Create Chart Directory Structure
The first step is to create a chart directory. Use helm create mychart to scaffold a standard structure. This creates a mychart/ directory with Chart.yaml, values.yaml, templates/, and other directories. This structure is the foundation of any Helm Chart and ensures consistency across all charts.
Define Metadata in Chart.yaml
Edit Chart.yaml to set the chart name, version, description, and any dependencies. The version field is important for Helm to track updates. Dependencies are declared here, not in templates. This file acts as the identity card for the chart and is used by Helm to resolve dependencies and determine version compatibility.
Write Template Files
In the templates/ directory, create YAML files for each Kubernetes resource your application needs, such as deployment.yaml, service.yaml, and ingress.yaml. These files use Go template syntax with placeholders like {{ .Values.replicaCount }}. The templates are the heart of the chart because they define exactly what Kubernetes objects will be created.
Set Default Values in values.yaml
The values.yaml file provides default values for all placeholders used in templates. For example, you might set replicaCount: 3 and image.repository: nginx. Users can later override these defaults. This separation of configuration from code is a key design principle of Helm, allowing different environments to reuse the same templates.
Manage Dependencies
If your chart depends on other charts (like a database chart), declare them in Chart.yaml under dependencies. Then run helm dependency update to download the charts into the charts/ subdirectory. This step ensures all required components are bundled together before installation, making the chart self-contained.
Test the Chart Locally
Before deploying to a live cluster, use helm lint to check for syntax errors and best practice violations. Use helm template to render the templates locally and inspect the output YAML without sending it to the cluster. This catches many mistakes early and saves troubleshooting time.
Install the Chart
Run helm install myrelease mychart/. This sends the chart to the Kubernetes API server, creates the resources, and records a new release named myrelease. Helm stores the release information in the cluster as a Secret, allowing future upgrades and rollbacks. This is the moment your application goes live.
Upgrade the Chart
To update the application, modify the chart or values, then run helm upgrade myrelease mychart/ -f new-values.yaml. Helm compares the current release state with the desired state, applies only the changes, and creates a new release revision. This enables zero-downtime updates when done correctly.
Rollback if Needed
If an upgrade causes issues, run helm rollback myrelease 1 to revert to revision 1 (the initial install). Helm reapplies the previous release state, restoring the cluster to that version. This is a critical safety net for production deployments and is a key feature that differentiates Helm from simple YAML apply.
Delete the Release
When the application is no longer needed, run helm uninstall myrelease. This removes all Kubernetes resources that were created as part of that release and deletes the release records. Cleanup is important to avoid orphaned resources in your cluster.
Practical Mini-Lesson
Helm Charts are essential for any Kubernetes practitioner, whether you are a developer deploying microservices or an operations engineer managing platform infrastructure. To use Helm effectively in practice, you need to understand three core concepts: charts, releases, and repositories. A chart is a package containing all the instructions to deploy an application.
A release is a specific instance of a chart running in a cluster. A repository is a collection of published charts that you can search and download. In a professional environment, you will rarely write charts from scratch for every application.
Instead, you will use existing charts from the Artifact Hub (hub.artifacthub.io) for common tools like Prometheus, Nginx Ingress, or Cert-Manager. For example, to monitor your cluster, you might run: helm repo add prometheus-community https://prometheus-community.
github.io/helm-charts && helm repo update && helm install prometheus prometheus-community/kube-prometheus-stack. This single command installs Prometheus, Alertmanager, and Grafana with pre-configured dashboards.
When you need custom applications, you create your own charts. The most common mistake beginners make is to put all configuration in the templates and ignore values.yaml. Always externalize configurable parameters.
For example, instead of hardcoding the image tag in deployment.yaml, use {{ .Values.image.tag }}. Then for production, set image.tag: 1.14.2 in a production-values.yaml. For development, use image.
tag: latest. Another critical practice is versioning. Always increment the chart version in Chart.yaml when you make changes. This allows Helm to track updates and enables rollbacks.
If you do not version, you may accidentally deploy the wrong combination of templates and values. Also, remember that Helm 3 stores release information in Secrets in the same namespace as the release. If you delete the namespace, you lose the ability to uninstall the release cleanly.
You would then need to delete resources manually or use helm uninstall with caution. In production, use Helm together with a GitOps tool like ArgoCD. ArgoCD can sync your Git repository containing chart values to the cluster automatically, ensuring that your cluster state always matches the desired state in Git.
This combination gives you auditability, version control, and automation. Finally, always test your chart changes in a non-production cluster before deploying to production. Use helm template to preview the output YAML.
Use helm lint to check for common errors. By following these practices, you will deploy Kubernetes applications with confidence, speed, and reliability.
Memory Tip
Think of Helm as the 'app store' for Kubernetes. The chart is the app package, the release is your purchase (a running instance), and the repository is the store. Remember the three commands that cover the full lifecycle: helm install (buy), helm upgrade (update), helm rollback (return).
Covered in These Exams
Related Glossary Terms
Two-factor authentication (2FA) is a security method that requires two different types of proof before granting access to an account or system.
5G is the fifth generation of cellular network technology, designed to deliver faster speeds, lower latency, and support for many more connected devices than previous generations.
802.1Q is the networking standard that allows multiple virtual LANs (VLANs) to share a single physical network link by tagging Ethernet frames with VLAN identification information.
802.1X is a network access control standard that authenticates devices before they are allowed to connect to a wired or wireless network.
Frequently Asked Questions
Is Helm only for Kubernetes?
Yes, Helm is specifically designed for Kubernetes. It packages and deploys Kubernetes resources, and it relies on the Kubernetes API server. It does not work with other container orchestration platforms.
Do I need to know Go to use Helm Charts?
No. Helm templates use the Go template language, but you do not need to be a Go developer. The syntax is simple: you use double curly braces to insert values and basic control structures like if/else. You can learn it quickly.
What is the difference between a chart and a release?
A chart is the package definition (the files and metadata). A release is a running instance of that chart in your cluster. You can install the same chart multiple times with different names, each creating a separate release.
How do I find publicly available Helm Charts?
The primary source is Artifact Hub (artifacthub.io), which aggregates charts from many repositories. You can also add specific chart repositories by URL using helm repo add, then search with helm search repo.
Can I use Helm without internet access?
Yes, but you need to have the chart files locally or on a local repository server. You can download charts from an internet-connected machine, package them with helm package, and transfer the .tgz file to the offline cluster.
What happens if I delete the namespace where a Helm release is installed?
All resources and the release secret are deleted along with the namespace. This means you cannot uninstall the release cleanly with helm uninstall. You would need to recreate the namespace or manually clean up leftover secrets.
Does Helm support custom resource definitions (CRDs)?
Yes, but they require special handling. Helm installs CRDs from a special crds/ directory before the templates. CRDs are not upgraded or deleted by default to avoid accidental data loss. You must manage CRD updates separately.
What is the Helm hook and when would I use it?
A Helm hook is a template annotation that tells Helm to run a resource at a specific point during the lifecycle, like before-install or after-delete. Hooks are used for tasks like database migrations or backup jobs.
Summary
Helm Charts are the standard way to package, deploy, and manage applications on Kubernetes. They combine all needed YAML configuration files into a single, versioned package that can be installed with one command. For IT certification learners targeting the KCNA exam, understanding Helm is essential because it is a core tool in the cloud native ecosystem.
The exam will test your knowledge of chart structure, release management, and basic Helm commands like install, upgrade, and rollback. Avoid common mistakes such as confusing helm install with helm upgrade, forgetting to update dependencies, or overlooking the security differences between Helm 2 and Helm 3. In real-world IT, Helm saves time, reduces errors, and enables consistent deployments across multiple environments.
It integrates with CI/CD pipelines and GitOps workflows, making it indispensable for platform engineers and DevOps teams. Remember that Helm is not a replacement for Kubernetes Operators or Kustomize; it serves a different purpose focused on packaging and lifecycle management. By mastering Helm Charts, you gain a powerful tool for cloud native application delivery, whether you are deploying a simple web app or a complex microservices architecture.
Study the commands, practice with real charts from Artifact Hub, and always keep the release lifecycle in mind.