Kubernetes 12 - Higher Deployment Abstractions in Kubernetes

As your infrastructure grows, you might find yourself needing more sophisticated tools to manage the increasing complexity. In this post, we’ll explore higher deployment abstractions in Kubernetes, focusing on popular tools and techniques that can streamline your deployment process.

The Kubernetes API

At the core of Kubernetes operations lies the Kubernetes API. When you run kubectl commands, you’re essentially communicating with this API. While powerful, the native Kubernetes API has some limitations:

Limited built-in templating capabilities
Basic versioning features
Minimal tracking and management tools for complex applications

These limitations have led to the development of numerous third-party tools designed to enhance Kubernetes deployments.

The Ecosystem of Deployment Tools

The Kubernetes ecosystem has seen an explosion of deployment tools, with over 60 third-party solutions emerging over time. However, it’s important to note that many of these tools have become defunct or are no longer actively maintained.

Among the survivors, a few standout options have gained significant traction:

Helm: Currently the most popular choice for Kubernetes package management.
Compose on Kubernetes: Integrated with Docker Desktop, providing a familiar interface for Docker Compose users.
Kustomize: An official Kubernetes feature for configuration customization.

Helm: THe Package Manager for Kubernetes

Helm has emerged as the de facto standard for managing Kubernetes applications. It offers several benefits:

Charts: Helm uses “charts” as packages of pre-configured Kubernetes resources.
Templating: It provides powerful templating capabilities for YAML files.
Release Management: Helm can manage releases and rollbacks of your applications.

Example of a simple Helm chart structure:

mychart/
  Chart.yaml
  values.yaml
  templates/
    deployment.yaml
    service.yaml

While Helm is powerful, it can have a steeper learning curve compared to some alternatives.

Kustomize: Native Kubernetes Configuration Management

As of Kubernetes 1.14, Kustomize has been integrated into kubectl,4 offering a native solution for customizing Kubernetes configurations. Kustomize allows you to:

Create base configurations and overlay them with environment-specific changes
Manage configurations without templates
Easily patch existing YAML files

Example of a Kustomize structure:

base/
  kustomization.yaml
  deployment.yaml
  service.yaml
overlays/
  production/
    kustomization.yaml
    production-patch.yaml
  staging/
    kustomization.yaml
    staging-patch.yaml

Docker’s Approach: Compose on Kubernetes and Docker App

For those familiar with Docker Compose, Docker offers two solutions that bridge the gap between Compose and Kubernetes:

Compose on Kubernetes: This allows you to deploy Docker Compose files directly to Kubernetes clusters.
docker app: A tool for packaging and managing distributed applications.

These tools can be particularly useful if you’re transitioning from a Docker Compose workflow to Kubernetes.

The Importance of YAML Templating

As your Kubernetes deployments grow in complexity and number, managing raw YAML files becomes increasingly challenging. Templating solutions offer several advantages:

Reduce duplication across similar deployments
Easily manage environment-specific configurations
Improve maintainability of your Kubernetes manifests

Most deployment tools, including Helm and Kustomize, offer some form of templating or customization to address these needs.

Conclusion

Higher-level abstractions can significantly simplify complex deployments. Whether you choose Helm for its comprehensive package management, Kustomize for its native integration, or Docker’s tools for familiarity, these solutions can help streamline your Kubernetes workflows.