virtualization feat(images): add DVCR image presence monitoring

Description

Implements periodic monitoring of DVCR (Deckhouse Virtualization Container Registry) image presence for VirtualImage and ClusterVirtualImage resources.

Key components:

ImageChecker: New component (pkg/dvcr/image_checker.go) that verifies image existence in DVCR registry using go-containerregistry
- Performs lightweight HEAD requests to check image manifests
Periodic Reconciliation: Uses controller-runtime's CronSource to trigger reconciliation on a configurable schedule
- Default: hourly (0 * * * *)
- Configurable via module config: dvcr.imageMonitorSchedule
- Can be disabled by setting empty string
Phase Management: New ImageLost phase added to track when images are deleted from DVCR
- ImageLost: Image manifest not found in DVCR registry
- ImagePVCLost: PVC backing the image was deleted (existing, renamed from PVCLost)
Optimizations:
- Custom field indexes (IndexVIByPhaseAndStorage, IndexCVIByPhase) to filter resources at API level

Why do we need it, and what problem does it solve?

When images are deleted from DVCR (either manually or due to storage issues), the VirtualImage/ClusterVirtualImage resources continue to show Ready phase even though the underlying image data is gone. This creates a misleading state where users think images are available but VM creation fails.

This feature provides automated detection of missing images and updates resource status accordingly, giving users accurate visibility into image availability.

What is the expected result?

Checklist

[ ] The code is covered by unit tests.
[ ] e2e tests passed.
[ ] Documentation updated according to the changes.
[ ] Changes were tested in the Kubernetes cluster manually.

Changelog entries

section: images
type: feature
summary:  Added monitoring of DVCR image presence for VirtualImage and ClusterVirtualImage

Oct 24 '25 13:10 loktev-d

Reviewer's Guide

Introduces a periodic DVCR image presence monitor for VirtualImage and ClusterVirtualImage using the existing GC framework and minimal API surface changes.

Sequence diagram for periodic DVCR image presence monitoring

sequenceDiagram
  participant CronScheduler
  participant ImageMonitorManager
  participant DVCRRegistry
  participant K8sAPI
  CronScheduler->>ImageMonitorManager: Trigger ListForDelete()
  ImageMonitorManager->>K8sAPI: List VirtualImage/ClusterVirtualImage
  loop For each Ready image
    ImageMonitorManager->>DVCRRegistry: CheckImageExists(registryURL)
    alt Image exists
      ImageMonitorManager-->>CronScheduler: No action
    else Image missing
      ImageMonitorManager->>K8sAPI: Update Status.Phase to ImageLost
      ImageMonitorManager->>K8sAPI: Set Condition Reason=ImageLost
    end
  end

ER diagram for updated VirtualImage and ClusterVirtualImage status phases

erDiagram
  VIRTUALIMAGE {
    string id
    ImagePhase phase
    string progress
    string registry_url
  }
  CLUSTERVIRTUALIMAGE {
    string id
    ImagePhase phase
    string progress
    string registry_url
  }
  IMAGEPHASE {
    string name
  }
  VIRTUALIMAGE ||--o| IMAGEPHASE : "has phase"
  CLUSTERVIRTUALIMAGE ||--o| IMAGEPHASE : "has phase"
  IMAGEPHASE {
    Pending
    Provisioning
    WaitForUserUpload
    Ready
    Failed
    Terminating
    ImageLost
    PVCLost
  }

Class diagram for DVCR image presence monitoring

classDiagram
  class VirtualImage {
    +Status: VirtualImageStatus
    +Spec: VirtualImageSpec
  }
  class ClusterVirtualImage {
    +Status: ClusterVirtualImageStatus
    +Spec: ClusterVirtualImageSpec
  }
  class VirtualImageStatus {
    +Phase: ImagePhase
    +Progress: string
    +Conditions: []Condition
    +Target: TargetInfo
  }
  class ClusterVirtualImageStatus {
    +Phase: ImagePhase
    +Progress: string
    +Conditions: []Condition
    +Target: TargetInfo
  }
  class ImagePhase {
    <<enum>>
    Pending
    Provisioning
    WaitForUserUpload
    Ready
    Failed
    Terminating
    ImageLost
    PVCLost
  }
  class ImageMonitorManager {
    +client: Client
    +dvcrSettings: DVCRSettings
    +New()
    +ShouldBeDeleted(obj)
    +ListForDelete(ctx, now)
    +checkImage(ctx, registryURL)
    +markImageLost(ctx, obj, registryURL)
    +getAuthCredentials(ctx)
  }
  class DVCRSettings {
    +AuthSecret: string
    +AuthSecretNamespace: string
    +InsecureTLS: string
  }
  class ImageChecker {
    <<interface>>
    +CheckImageExists(ctx, imageURL)
  }
  class DefaultImageChecker {
    +username: string
    +password: string
    +insecure: bool
    +CheckImageExists(ctx, imageURL)
  }
  VirtualImageStatus --> ImagePhase
  ClusterVirtualImageStatus --> ImagePhase
  ImageMonitorManager --> DVCRSettings
  ImageMonitorManager --> ImageChecker
  DefaultImageChecker ..|> ImageChecker

File-Level Changes

Change	Details	Files
Extend GC settings to include image monitor schedule	Add GcImageMonitorScheduleVar Implement GetImageMonitorSettingsFromEnv Add NewDefaultImageMonitorSettings	`pkg/config/load_gc_settings.go`
Implement image-monitor controllers for VI and CVI	Setup GC cron source List ready CRs and check DVCR via ImageChecker Update status to ImageLost on absence	`pkg/controller/vi/image_monitor.go` `pkg/controller/cvi/image_monitor.go`
Provide DVCR ImageChecker	Use go-containerregistry HEAD request Support basic auth and TLS options Error handling for not-found vs other failures	`pkg/dvcr/checker.go`
Enhance CRDs with ImageLost/PVCLost semantics	Add ImageLost and PVCLost reasons and phases Update enum validation to include new values Deprecate Lost alias	`api/core/v1alpha2/virtual_image.go` `api/core/v1alpha2/cluster_virtual_image.go` `api/core/v1alpha2/image_status.go` `api/core/v1alpha2/vicondition/condition.go` `api/core/v1alpha2/cvicondition/condition.go`
Align PVC source controller with PVCLost	Rename Lost reason to PVCLost Use ImagePVCLost phase for PVC errors Update tests accordingly	`pkg/controller/vi/internal/source/step/ready_pvc_step.go` `pkg/controller/vi/internal/source/sources.go` `pkg/controller/vi/internal/source/object_ref_vdsnapshot_pvc_test.go`
Report new phases in metrics	Include ImageLost and ImagePVCLost in scraper phases	`pkg/monitoring/metrics/vi/scraper.go` `pkg/monitoring/metrics/cvi/scraper.go`
Bump dependencies for image checking	Add google/go-containerregistry Update docker/cli version	`go.mod`

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Oct 24 '25 13:10 sourcery-ai[bot]

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Nov 18 '25 07:11 deckhouse-BOaTswain

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Nov 20 '25 14:11 deckhouse-BOaTswain