Image Controller

Overview

Image controller sets up and manages container image repositories in configured quay.io organization. It works either for general purpose image repository or Component-specific image repository.

The image controller can perform multiple actions with use of ImageRepository custom resources.

• Setup image repository: create an image repository and a robot accounts which are specific to that repository for image push and pull. A Kubernetes Secret objects are also created with push and pull robot account tokens, in order to make it available for build PipelineRun via service account.

• Modify repository visibility: switch an image repository’s visibility between public and private.

• Rotating credentials for repository: rotate repository credentials, and update relevant secrets.

• Verify and fix secrets linked to ServiceAccount: verify and fix linking of secrets to ServiceAccount.

• Cleanup: When a Component CR is requested to be deleted, image controller will remove component’s image repository (Component owns ImageRepository) and robot account from the remote registry (it is possible to skip repository removal). The Kubernetes Secret will be removed along with the Component CR eventually due to the ownership established between them (ImageRepository owns Secret).

Dependencies

Image controller does not depend on other Konflux services, but a remote image registry. Konflux services are able to use the resources prepared by image controller, e.g. ServiceAccount with linked Secrets is available to every build PipelineRun of a component for pushing image.

# Controllers

The Image Controller contains these controllers:

• Image controller
  • Monitors ImageRepository CRs and creates image repository, robot accounts and links secret to service accounts.
• Application controller
  • Monitors Application CRs, creates application specific service account $APPLICATION_NAME-pull and links there (to both secrets and imagePullSecrets sections) all pull secrets from all Components in the Application.

Interface

# ImageRepository CR

The ImageRepository CR is the interface to interact with image controller to create and manage image repositories in a registry.

# To create an general purpose image repository, apply this YAML code:

apiVersion: appstudio.redhat.com/v1alpha1
kind: ImageRepository
metadata:
    name: imagerepository-for-component-sample
    namespace: test-ns

As a result, a public image repository quay.io/my-org/test-ns/imagerepository-for-component-sample will be created, based on $DEFAULT_REGISTRY_ORG/$USER_NAMESPACE/$IMAGE_REPOSITORY_NAME.

• DEFAULT_REGISTRY_ORG - is taken from quay secret in the cluster
• USER_NAMESPACE - is taken from ImageRepository .metadata.namespace
• IMAGE_REPOSITORY_NAME - is taken from ImageRepository .metadata.name

Two robot accounts and corresponding Kubernetes Secrets for push and pull are created.

# To create an image repository for a Component, apply this YAML code:

apiVersion: appstudio.redhat.com/v1alpha1
kind: ImageRepository
metadata:
    name: imagerepository-for-component-sample
    namespace: test-ns
    annotations:
        image-controller.appstudio.redhat.com/update-component-image: 'true'
    labels:
        appstudio.redhat.com/component: my-component
        appstudio.redhat.com/application: my-app

As a result, a public image repository quay.io/my-org/test-ns/my-component will be created, based on $DEFAULT_REGISTRY_ORG/$USER_NAMESPACE/$COMPONENT_NAME.

• DEFAULT_REGISTRY_ORG - is taken from quay secret in the cluster
• USER_NAMESPACE - is taken from ImageRepository .metadata.namespace
• COMPONENT_NAME - is taken from Component .metadata.name

Two robot accounts and corresponding Kubernetes Secrets for push and pull are created.

It will also link push secret to component specific service account build-pipeline-$COMPONENT_NAME used for build pipelines (secrets section).

And it will also link pull secret to application specific service account $APPLICATION_NAME-pull (to both secrets and imagePullSecrets sections).

Annotation image-controller.appstudio.redhat.com/update-component-image is required when using ImageRepository with Component, as it will set Component’s spec.containerImage allowing Build service controller to continue.

# User defined repository name

One may request custom image repository name by setting spec.image.name field upon the ImageRepository object creation, but it will always be prepended by $DEFAULT_REGISTRY_ORG/$USER_NAMESPACE.

e.g. when spec.image.name is set to my-repository final repository url will be $DEFAULT_REGISTRY_ORG/$USER_NAMESPACE/my-repository.

Note, it’s not possible to change image repository name after creation. Any changes to the field will be reverted by the operator.

# Setting quay.io notifications

Notifications can be set with:

spec:
  notifications:
  - config:
      url: https://bombino.api.redhat.com/v1/sbom/quay/push
    event: repo_push
    method: webhook
    title: SBOM-event-to-Bombino

# Changing repository visibility

By default, a public image repository is created. To change the image repository visibility, set public or private to .spec.image.visibility.

# Credentials rotation for repository

To regenerate tokens push and pull, set true to .spec.credentials.regenerate-token, it will also re-create secrets.

After token rotation, the spec.credentials.regenerate-token section will be deleted and status.credentials.generationTimestamp updated.

# Verify and fix secrets linked to ServiceAccount

• It will link secret to service account if link is missing.
• It will remove duplicate links of secret in service account.
• It will remove secret from imagePullSecrets in service account.

To perform verification and fix, set true to .spec.credentials.verify-linking.

After verification, the spec.credentials.verify-linking section will be deleted.

# Skip repository deletion

By default, if the ImageRepository resource is deleted, the repository it created in registry will get deleted as well.

In order to skip the removal of the repository, set true to image-controller.appstudio.redhat.com/skip-repository-deletion annotation.

# Status explanation

ImageRepository CR has .status which includes all final information about an image repository:

status:
  credentials:
    generationTimestamp: '2025-03-21T14:28:59Z'
    pull-robot-account: test_pull
    pull-secret: imagerepository-for-test-image-pull
    push-robot-account: test_push
    push-secret: imagerepository-for-test-image-push
  image:
    url: quay.io/redhat-user-workloads/test-tenant/test
    visibility: public
  notifications:
    - title: SBOM-event-to-Bombino
      uuid: aaaaa-......
  state: ready

• .status.credentials includes info about credentials.
  • generationTimestamp timestamp from when credentials were updated.
  • pull-robot-account robot account name in configured registry organization with read permissions to the repository
  • pull-secret Secret of dockerconfigjson type that contains image repository pull robot account token with read permissions.
  • push-robot-accountrobot account name in configured registry organization with write permissions to the repository
  • push-secret Secret of dockerconfigjson type that contains image repository push robot account token with write permissions.
• .status.image includes the full repository URL and current visibility.
• .status.notification shows info about notifications.
• .status.state shows whether image controller responded last operation request successfully or not.

# Legacy interaction via Component annotations

Image controller uses annotations to interact with external services.

• image.redhat.com/generate: An external service is able to request an image repository for an application component by setting this annotation on the corresponding Component CR. For initial request, the value should include field visibility to indicate the visibility of the created image repository in the remote registry, and it can be set again subsequently to change the visibility on demand. Note that, this annotation will be removed once requested operation finishes.

  Here is an example that requests a private image repository:

  image.redhat.com/generate: '{"visibility": "private"}'
  

• image.redhat.com/image: image controller provides information of prepared resources to external services via this annotation, which includes the image repository URL, the visibility of that repository, and a secret name pointing to the created Kubernetes Secret.

  If something went wrong during the requested operation, this annotation will include a field Message with a corresponding error message.

  Here is an example that shows a public image repository is ready on Quay.io and a Secret named secret-name contains a robot account token and is available for image push.

  image.redhat.com/image: "{\"image\":\"quay.io/redhat-user-workloads/image-controller-system/city-transit/billing\",\"visibility\":\"public\",\"secret\":\"secret-name\"}"