Platform Engineers

Flux with Kustomize for Application Environment Management

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Platform Engineers
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2 min read

In the context of application environment management, maintaining consistency and reproducibility across different environments is crucial. This can be achieved by utilizing Flux and Kustomize, two powerful tools that work together to manage and configure application environments efficiently.

Flux

Flux is an open-source tool that automates the deployment and management of applications on Kubernetes. It provides a GitOps approach, where the desired state of the application is defined in a Git repository. Flux continuously monitors the repository and applies any changes to the application environment, ensuring that the environment remains in sync with the defined state.

Kustomize

Kustomize is a tool for customizing Kubernetes configurations. It allows users to define a base configuration and then apply overlays to customize the configuration for different environments. Kustomize supports a wide range of customization options, including variable substitution, patching, and merging.

Integration of Flux and Kustomize

To integrate Flux and Kustomize, the Kustomize configuration is stored in the same Git repository as the application code. Flux monitors the repository and applies the Kustomize configuration to the application environment.

Here is an example of how the integration works:

# kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization

resources:
  - deployment.yaml
  - service.yaml

configMapGenerator:
  - name: env-config
    envs:
      - env.properties

# deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-app

spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-app
        image: my-app:latest

# service.yaml
apiVersion: v1
kind: Service
metadata:
  name: my-app

spec:
  selector:
    app: my-app
  ports:
  - name: http
    port: 80
    targetPort: 8080

# env.properties
DB_HOST=localhost
DB_PORT=5432

In this example, the kustomization.yaml file defines the base configuration for the application. The deployment.yaml and service.yaml files define the deployment and service configurations, respectively. The env.properties file defines environment variables for the application.

When Flux detects changes to the repository, it applies the Kustomize configuration to the application environment. The resulting configuration is a customized deployment and service that reflect the environment variables defined in env.properties.

The integration of Flux and Kustomize provides a robust platform for managing application environments. By storing the Kustomize configuration in the same Git repository as the application code, the entire application environment can be managed and versioned as a single unit. This approach enables platform engineers to manage complex application environments efficiently and consistently.

Conclusion

In conclusion, the integration of Flux and Kustomize provides a powerful toolset for managing application environments. By utilizing Kustomize for customization and Flux for automation, developers can ensure consistency and reproducibility across different environments. This approach enables efficient management of complex application environments and is particularly useful in large-scale, distributed systems.

Platform Engineering