Helm Chart Dependencies: Overview and Best Practices 2023

If your work is remotely connected to Kubernetes, chances are you've heard of Helm. Helm is a popular package manager for Kubernetes which you can use to define, install, and manage applications or services via a collection of YAML files, also known as Helm charts. Now, these charts are rather versatile and can be used to package everything from simple applications to complex, multi-tiered services, making it easy for you to deploy and manage your Kubernetes workloads.

So why are we talking about Helm charts? For one, they are a game changer in the DevOps space as they make it easy to get started with Kubernetes. Helm works by abstracting away some of the complexities of the platform so you never have to worry about the details of how things work or how they are configured. Moreover, Helm charts make it easier to share and reuse configuration and applications across teams, so you don't need to reinvent the wheel each time you deploy a new service.

However, there’s one key aspect of Helm charts that is essential for understanding their power — dependencies. Helm chart dependencies allow you to package and deploy related applications or services together. This helps ensure that all the necessary components are installed and configured correctly. Without dependencies, managing complex Kubernetes workloads can become overwhelming very quickly. 

In this post, we'll explore Helm chart dependencies in further detail and explain how you can use them to streamline your K8s deployment workflows.

What are Helm Chart dependencies and why are they important?

As described above, in Helm, we can manage dependencies between different applications and services in a Kubernetes cluster where one chart relies on another. For instance, imagine you're deploying a modern e-commerce website (which includes both a frontend and a backend database). With Helm, you can package and deploy these two components as separate charts — with the frontend chart relying on the backend chart for its data storage needs. Whenever you deploy the frontend chart, Helm will automatically check for any required dependencies and ensure that the backend chart is up and running first. 

The ability to specify and manage these dependencies is key to managing complex Kubernetes workloads, where there may be many different components that need to be installed and configured. Without dependencies, you would need to manually install and configure each component, which can quickly become overwhelming and error-prone.

Furthermore, Helm chart dependencies also make it easier to share and reuse configuration and applications across teams. By packaging related applications or services together, you can create a consistent and repeatable deployment process that can be used by anyone in your organization. By specifying the required version or range of versions for each dependency, you can ensure that all the components work together correctly. This can help to prevent issues like version conflicts or compatibility problems that can arise when managing complex Kubernetes workloads.

Managing Helm Chart dependencies

Managing dependencies in Helm charts is a straightforward process. To declare dependencies, you need to add a ‘dependencies’ section to the Chart.yaml file. This section lists all the dependencies required for the chart, along with their version constraints. Here's an example dependencies section:

dependencies:
- name: mariadb
version: 10.x.x
repository: https://charts.bitnami.com/bitnami

In this example, the chart has a single dependency on the MariaDB database, with a version constraint of ‘10.x.x’. The chart specifies the repository from which to download the dependency.

Once you have declared your dependencies, you can install them using the ‘helm dependency update’ command. This command will fetch all the dependencies listed in the ‘Chart.yaml’ file and store them in a charts/ directory within the chart.

Now, when you install the chart, Helm will automatically install all the dependencies along with the chart itself, ensuring that everything is set up correctly.

CI/CD pipelines and Helm repositories can help manage dependencies more efficiently. In a CI/CD pipeline, you can use the ‘helm dependency build’ command to create a tarball of the chart with all its dependencies included. This tarball can then be uploaded to a Helm repository, where it can be easily downloaded and installed by other teams or environments.

Helm repositories can also be used to store dependencies separately from charts, making it easy to reuse and share dependencies across multiple charts. By referencing a shared dependency in a ‘requirements.yaml’ file, you can ensure that all charts that use the dependency are using the same version.

In short, managing Helm chart dependencies is an essential part of managing more complex Kubernetes workloads. By declaring dependencies in the ‘Chart.yaml’ file, and using tools like CI/CD pipelines and Helm repositories, you can streamline your deployment workflows, reduce the risk of errors, and ensure consistency across your deployments.

Best practices for managing Helm Chart dependencies

Here are some best practices for managing Helm chart dependencies:

1. Declare all dependencies in the ‘Chart.yaml’ file: It's essential to declare all dependencies in the chart's ‘Chart.yaml’ file, including their version constraints and repositories. This ensures that all dependencies are installed correctly and that there are no conflicts or version mismatches.
2. Use specific version constraints: Instead of using generic version constraints like ‘~x.y.z’ or ‘^x.y.z’, it's best to use specific version constraints to ensure that the correct version of a dependency is installed. For example, using ‘=x.y.z’ ensures that only version ‘x.y.z’ of the dependency is installed.
3. Update dependencies regularly: This ensures that you're using the latest and most secure versions of your dependencies.
4. Use a private Helm repository: Instead of relying on public Helm repositories, it's advisable to use a private Helm repository to store and share your charts and dependencies. This ensures that you have more control over the versions of your dependencies and reduces the risk of unexpected changes or version conflicts.
5. Test and document your dependencies:  Before deploying your charts and dependencies in a production environment, it's a best practice to test them thoroughly in a staging or testing environment. This ensures that everything works as expected and reduces the risk of errors or downtime in production. And documenting them saves you from unnecessary trouble in the future.

Conclusion

All in all, Helm charts have become a crucial tool for deploying and managing complex workloads in the Kubernetes ecosystem. To that end, it’s important that you manage your Helm chart dependencies properly to ensure consistent, reliable, and secure deployments. By declaring all dependencies in the ‘Chart.yaml’ file, using specific version constraints, updating dependencies regularly, and testing your dependencies, you can manage your Helm chart dependencies efficiently. These best practices will help to reduce the risk of version conflicts, errors, and downtime in production environments. 

If you're looking for help with managing your Helm chart dependencies, Kubiya can help. As a leading provider of DevOps self-serve for Kubernetes, Kubiya specializes in helping Devs automate the deployment of scalable and secure applications on the cloud while freeing Ops to focus on core innovation.
Find out more today!