Package managers

Introduction #

Package managers in Kubernetes simplify the deployment, management and configuration of applications in the cluster. They let you describe, manage and automate complex deployments through standardised configuration files.

Helm #

The most popular package manager for Kubernetes.

Overview #

Helm is a package manager for Kubernetes that automates the deployment and management of applications. It uses “charts” to package and version complete applications.

Features #

Helm lets you manage application versions, define custom configuration values and simplify repetitive deployments thanks to templates.

Usage example #

helm install my-app stable/my-chart

This command installs a chart named my-app from the stable repository.

Kustomize #

A template-free approach to configuration management.

Overview #

Kustomize lets you manage Kubernetes configurations without needing templates. It applies transformations to YAML resources to customise deployments, while avoiding file duplication.

Features #

Kustomize handles overlays and YAML patches, and makes it easier to manage multiple environments with specific variations without duplicating resources.

Usage example #

kustomize build ./my-app

This command generates the deployment configuration by applying the overlays defined in my-app.

Carvel #

A suite of tools for managing Kubernetes applications.

Overview #

Carvel is a collection of Kubernetes configuration management tools, offering a modular approach to packaging, dependency management and dynamic application configuration.

Features #

Carvel includes tools such as ytt for templating, kbld for image management and kapp for deploying and managing resources.

Usage example #

ytt -f config/ | kapp deploy -a my-app -f -

This command uses ytt to generate the configurations and kapp to deploy the application.

GitOps #

A deployment management approach based on version control.

Overview #

GitOps is a methodology in which the source code in a Git repository represents the desired state of the Kubernetes cluster. Configuration changes made in Git automatically trigger cluster updates through operators such as ArgoCD or Flux.

Features #

GitOps provides traceability of changes, version management and configuration auditing by keeping a history in Git.

Usage example #

kubectl apply -f https://github.com/my-org/my-app-config

This command synchronises the cluster with the application configurations defined in Git.

Operator #

Advanced application management through dedicated controllers. That said, more and more operators are now deployed via HELM.

Overview #

Operators let you manage complex applications through dedicated Kubernetes controllers. They automate state and lifecycle management for applications that require particular configurations and dependencies.

Features #

Operators encapsulate application-specific logic such as database backups, scaling and rolling updates, while respecting the application's own practices.

Usage example #

kubectl apply -f my-operator.yaml

This command installs an Operator dedicated to managing a complex application.

Choosing a package manager #

• Helm: for packaged applications and simple deployments with many templates.
• Kustomize: for deployments that need fine-grained customisation without duplicating configurations.
• Carvel: for a modular, flexible approach with dedicated tools for each task.
• GitOps: for environments where configurations must be versioned and audited.
• Operator: for complex applications whose dependencies and lifecycles are managed automatically.