This document provides a step-by-step guide for configuring Docker within the development environment of fluxcd/flux2-multi-tenancy. It will focus on how Docker is utilized specifically for this purpose, omitting any production-related details.

Step 1: Set Up the Docker Environment

Ensure that Docker is installed and running on your development machine. Confirm the installation by executing:

$ docker --version

Step 2: Clone the Tenant Git Repository

Before proceeding, verify that the tenant Git repository has been cloned properly. This entails checking the sources registered by Flux. Run the following command:

$ flux -n apps get sources git

An expected output should resemble:

NAME        READY    MESSAGE
dev-team    True     Fetched revision: dev-team/ca8ec25405cc03f2f374d2f35f9299d84ced01e4

Step 3: Verify Helm Repository Index

Next, confirm that the Helm repository index has been downloaded. Execute:

$ flux -n apps get sources helm

You should see output similar to:

NAME        READY    MESSAGE
podinfo     True     Fetched revision: 2022-05-23T10:09:58.648748663Z

Step 4: Install the Demo Application

Monitor the installation of the demo application by watching the Helm releases:

$ watch flux -n apps get helmreleases

Once the app is installed, the output should indicate:

NAME        READY    MESSAGE                          REVISION    SUSPENDED
podinfo     True     Release reconciliation succeeded   5.0.3      False

Step 5: Build Docker Images for Development

In the development environment, you can build Docker images that are compatible with the Flux infrastructure. Create a Dockerfile in your application directory for your demo app.

Example Dockerfile:

FROM ghcr.io/fluxcd/source-controller:v0.14.1

COPY . /app

WORKDIR /app

RUN go build -o myapp

ENTRYPOINT ["./myapp"]

After creating the Dockerfile, build the image:

$ docker build -t myapp:latest .

Step 6: Running the Docker Image

To test the Docker image locally, run the following command:

$ docker run --rm myapp:latest

Step 7: Manage Kubernetes Deployments with Docker

When utilizing Docker images in your Kubernetes environment, ensure the configuration properly reflects namespaces and deployment settings defined in the multi-tenancy setup.

For example, the kustomization.yaml should reference your Docker image:

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

images:
  - name: myapp
    newName: ghcr.io/myorg/myapp
    newTag: latest

Step 8: Ensure Provenance of Container Images

Use policies to verify the provenance of images. For instance, here’s a sample Kyverno policy to verify Flux images:

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: verify-flux-images
spec:
  validationFailureAction: enforce
  rules:
    - name: verify-image-signature
      match:
        resources:
          kinds:
            - Pod
      verifyImages:
        - imageReferences:
            - "docker.io/fluxcd/source-controller:*"
            - "docker.io/myorg/myapp:*"
          attestors:
            - entries:
                - keyless:
                    subject: "https://github.com/fluxcd/*"

Conclusion

This document has guided you through the process of configuring Docker within the development environment for fluxcd/flux2-multi-tenancy. With these steps, you can successfully build, run, and verify your Docker images in accordance with Flux’s multi-tenancy principles.

Sources:

• Implementations and examples referenced are sourced from the README.md and configuration files in the repository.