In this blog, we explore the nuances of Kubernetes deployment tools - Helm, Kustomize, and Manifests. We’ll explain their differences, and gain practical insights into their usage through quickstart guides.

Introduction

Kubernetes (K8S) might be the de facto standard for container orchestration nowadays, offering unparalleled scalability, resilience, and flexibility for deploying and managing cloud-native applications. As organizations increasingly embrace Kubernetes, the need for efficient application deployment practices grows to harness its full potential.

At its core, Kubernetes provides a powerful platform for automating the deployment, scaling, and management of containerized applications across distributed environments. However, managing configurations and dependencies of Kubernetes resources can be a daunting task, especially for complex applications.

To address these challenges, developers and operators turn to a diverse array of tools and methodologies tailored for Kubernetes application deployment. Among these tools, Helm, Kustomize, and Manifest files stand out as popular choices within the Kubernetes ecosystem, each offering unique capabilities and approaches to streamlining the deployment process.

Let’s delve into the nuances of Helm, Kustomize, and Manifest files, exploring their roles, features, and practical applications in Kubernetes deployment workflows.

Understanding Helm

Helm is a powerful package manager for Kubernetes applications designed to simplify the process of defining, installing, and upgrading complex applications on Kubernetes clusters. It provides a standardized way of packaging, distributing, and managing Kubernetes applications and their dependencies.

At the core of Helm lies the concept of charts. A Helm chart is a collection of files that describe a set of Kubernetes resources necessary to run a specific application. These resources can include Deployments, Services, ConfigMaps, Secrets, PersistentVolumes, and more.

The structure of a Helm chart typically consists of the following directories and files:

• Chart.yaml: This file contains metadata about the chart, such as its name, version, description, maintainers, and dependencies.
• values.yaml: This file defines default configuration values for the chart. These values can be overridden or customized during installation or upgrade using user-provided values files.
• templates/: This directory contains templated YAML files representing Kubernetes resources. These templates use Go’s text/template syntax and allow for dynamic generation of Kubernetes manifests based on the values provided by the user.
• charts/: This directory can contain dependencies in the form of other Helm charts. These dependencies are managed by Helm and can be declared in the Chart.yaml file.
• helpers/: This directory contains helper templates and partials that can be included in the main templates to simplify and modularize chart definitions.

Quickstart Guide for Helm

To start using Helm, we first need to install it. To install Helm, you can use either the Helm installer script or package managers like Homebrew (for macOS/Linux) or Chocolatey (for Windows). For example, to install Helm using the installer script, run the following commands:

curl -fsSL -o get_helm.sh https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3
chmod 700 get_helm.sh
./get_helm.sh

Helm uses repositories to store and distribute charts. Before deploying applications, you may need to add Helm repositories containing the charts you want to use. Use the following command to add a repository:

helm repo add <repository_name> <repository_url>

Besides adding repositories, you can start creating your own Helm chart from a basic template and customize it for deploying applications on Kubernetes. Here’s a basic example of deploying a simple Nginx web server using Helm. First, create a Helm chart for the Nginx web server. Run the following command to create a new Helm chart named my-nginx:

helm create my-nginx

Navigate to the my-nginx directory and edit the values.yaml file to customize the chart’s configuration, such as specifying the number of replicas, setting resource limits, or defining environment variables. Next, install the Helm chart to deploy the Nginx web server by running the following command:

helm install my-nginx ./my-nginx

You’ve now successfully deployed an application using Helm.

Exploring Kustomize

Kustomize is a powerful tool used for customizing Kubernetes resources without directly modifying the original YAML files. It provides a declarative approach to configuration management, allowing users to make modifications, additions, or deletions to Kubernetes resource definitions in a structured and controlled manner.

Kustomize organizes configuration management through the use of a “base” configuration and “overlays.” The base configuration represents the common configuration shared across multiple environments, while overlays contain environment-specific changes that are applied on top of the base configuration.

The structure of a Kustomize project typically includes the following components:

• Base Configuration: The base configuration consists of YAML files defining the common configuration for the application. This can include Deployments, Services, ConfigMaps, Secrets, and other Kubernetes resources necessary for the application to run.
• Overlays: Overlays are directories containing environment-specific modifications to the base configuration. Each overlay can contain YAML files that add, modify, or remove fields in the base resources. Overlays enable users to customize configurations for different environments like development, staging, and production without duplicating or modifying the base configuration.
• Kustomization.yaml: This file serves as the entry point for Kustomize and specifies the resources to be customized and the overlays to apply. It also allows users to define transformations, patches, and other configuration options.

Quickstart Guide for Kustomize

Kustomize comes bundled with kubectl as a subcommand, so you don’t need to install it separately. Ensure you have kubectl installed and configured to interact with your Kubernetes cluster.

To use Kustomize, you’ll need to create a kustomization.yaml file in the directory containing your Kubernetes resource manifests. Here’s a basic example of deploying an application using Kustomization.

Navigate to the directory where your Kubernetes manifests are located, and create a kustomization.yaml file with the following content:

apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
resources:
- deployment.yaml
- service.yaml

If needed, customize the individual Kubernetes manifests (deployment.yaml, service.yaml, etc.) to specify configurations such as labels, annotations, or environment variables. You can apply the Kustomization to deploy the Nginx web server by running the following command:

kubectl apply -k .

You’ve now successfully deployed an application using Kustomize.

Leveraging Manifests

Manifest files are fundamental YAML or JSON documents that directly describe Kubernetes resources such as Deployments, Services, ConfigMaps, Secrets, and more. They serve as the blueprint for the desired state of Kubernetes resources within a cluster.

Manifest files are written in YAML or JSON format and typically include specifications for various Kubernetes objects, each defined as a separate resource within the file. These resources specify details such as container images, resource limits, environment variables, ports, labels, annotations, and other configuration parameters necessary for deploying and managing applications on Kubernetes.

Quickstart Guide for Manifest files

Manifest files are simple YAML or JSON documents that directly describe Kubernetes resources. You can create these files using a text editor of your choice. Here’s a basic example of deploying a simple Nginx web server.

First, create YAML files for the Kubernetes resources required to deploy an Nginx web server. For example, you might create nginx-deployment.yaml for the Deployment and nginx-service.yaml for the Service. In each YAML file, define the Kubernetes resources required for the Nginx deployment. For instance, in nginx-deployment.yaml, you might define a Deployment resource, and in nginx-service.yaml, you might define a Service resource.

# nginx-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80

# nginx-service.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  selector:
    app: nginx
  ports:
    - protocol: TCP
      port: 80
      targetPort: 80
  type: NodePort

Now you can apply the Manifest files to your Kubernetes cluster using kubectl apply command. For example:

kubectl apply -f nginx-deployment.yaml
kubectl apply -f nginx-service.yaml

You’ve successfully deployed a Nginx web server using Manifest files.

Comparing Helm, Kustomize, and Manifests

The choice between Helm, Kustomize, and Manifests depends on factors such as ease of use, flexibility, scalability, and specific deployment requirements. By understanding the strengths, weaknesses, and considerations for each tool, you can make informed decisions to optimize your Kubernetes deployment workflows effectively. Let’s dive into these factors.

Ease of Use

Helm provides a high level of abstraction, making it relatively easy to package, install, and manage Kubernetes applications using pre-defined charts. Its templating system allows for parameterization and customization, further simplifying the deployment process. Kustomize offers a more granular approach to configuration management, which may require a steeper learning curve compared to Helm. However, once understood, Kustomize provides a straightforward mechanism for customizing Kubernetes resources without modifying the original YAML files. Manifest files offer the most direct and explicit approach to defining Kubernetes resources. While they may require more manual effort compared to Helm or Kustomize, they provide maximum control and transparency over configurations.

Flexibility

Helm’s templating system and chart structure provide a high degree of flexibility for defining and customizing Kubernetes resources. Users can easily parameterize and modularize configurations, allowing for reuse across different environments and applications. Kustomize offers flexibility through overlays, enabling users to customize configurations for different environments and use cases. Its declarative approach allows for fine-grained control over resource modifications without altering the base configuration. Manifest files offer the greatest flexibility as they directly represent the desired state of Kubernetes resources. Users have complete control over resource definitions and can tailor configurations to meet specific requirements.

Scalability

Helm is well-suited for managing complex deployments involving multiple components and dependencies. Its chart-based approach facilitates modularization and reuse, making it easy to scale applications across different clusters and environments. Kustomize scales well with growing complexity and size of deployments. Its overlay-based structure allows for incremental changes and updates, minimizing the risk of configuration drift and ensuring consistency across environments. Manifest files are highly scalable and can be used to define configurations for deployments of any size or complexity. However, managing large numbers of manifest files manually may become cumbersome over time without proper organization and tooling.

Deployment Process

Helm is well-suited for managing complex deployments with many interdependent components. It provides versioning, rollback, and dependency management capabilities out of the box. However, the Chart-based approach may introduce overhead for simple deployments. Templating can become complex and difficult to maintain for large charts. Kustomize offers fine-grained control over configuration management with overlays. It allows environment-specific customizations without modifying the base configuration. It does require familiarity with YAML and Kubernetes resource definitions, and may lack built-in features for versioning and dependency management compared to Helm. Manifest files give you maximum control and transparency over Kubernetes configurations. It is suitable for scenarios requiring explicit resource definitions and minimal abstraction. However, manual management of manifest files can be time-consuming and error-prone, especially for large deployments. Manifest files lack built-in features for templating and parameterization, which may require additional tooling.

Choosing the Right Tool

For simple deployments, Manifests may suffice, while Helm or Kustomize may be more appropriate for managing complex configurations with many components and dependencies. But, if fine-grained control over configuration management is required, Kustomize offers more flexibility through overlays. Helm may be preferred for applications with standardized configurations and templating needs.

Make sure you consider the familiarity and expertise of your team with each tool. Choose the tool that aligns best with the team’s skillset and preferences to minimize learning curves and maximize productivity. Additionally, evaluate how each tool integrates with existing CI/CD pipelines, version control systems, and deployment workflows. Choose the tool that seamlessly fits into the existing toolchain and infrastructure.

Closing words

Helm, Kustomize, and Manifest files each offer unique capabilities and approaches to managing Kubernetes configurations, catering to diverse deployment scenarios and requirements. Understanding these tools' strengths and trade-offs is key to successful deployments. Consider your deployment’s complexity and customization requirements. Helm simplifies package management, while Kustomize allows fine-grained configuration adjustments. Manifest files provide ultimate control but may require more manual effort.

Ultimately, the right tool depends on your specific deployment needs and preferences. By leveraging these tools effectively, you can streamline your Kubernetes deployments and achieve success with confidence. Stay flexible and adaptable in your approach. Embrace continuous learning and experimentation to optimize deployment workflows and stay ahead in the Kubernetes ecosystem.

Thank you for taking the time to go through this post and making it to the end. Stay tuned, because we’ll keep continuing providing more content on topics like this in the future.