fix(vmbda): report error when device is unavailable on VM node #1561

loktev-d · 2025-10-10T11:49:41Z

Description

Add condition error for PersistentVolume node affinity when attached block devices via VMBDA is not available on VM node.

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

When using storage classes with node affinity, the PersistentVolume is pinned to a specific node. If a user tries to hot-plug such a disk to a VM running on a different node, the attachment fails silently or with unclear errors.

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: vmbda
type: fix
summary:  VMBDA now reports a clear error if the device is not available on the VM's node.

Signed-off-by: Daniil Loktev <[email protected]>

sourcery-ai · 2025-10-10T11:49:47Z

Reviewer's Guide

Adds explicit node affinity validation for PersistentVolumes in VMBDA: AttachmentService now fetches the PV and target Node to verify the volume’s node affinity, and the handler fails hot-plug operations with a clear 'DeviceNotAvailableOnNode' status when the PV isn’t available on the VM’s node.

Sequence diagram for VMBDA block device attachment with node affinity validation

sequenceDiagram
    participant "LifeCycleHandler"
    participant "AttachmentService"
    participant "PersistentVolumeClaim (PVC)"
    participant "PersistentVolume (PV)"
    participant "Node"
    participant "VirtualMachineInstance (kvvmi)"
    actor "User"

    "User"->>"LifeCycleHandler": Request block device attachment
    "LifeCycleHandler"->>"AttachmentService": GetPersistentVolumeClaim(ad)
    "AttachmentService"->>"PersistentVolumeClaim (PVC)": Fetch PVC
    "AttachmentService"->>"LifeCycleHandler": Return PVC
    "LifeCycleHandler"->>"AttachmentService": IsPVAvailableOnVMNode(pvc, kvvmi)
    "AttachmentService"->>"PersistentVolume (PV)": Fetch PV
    "AttachmentService"->>"Node": Fetch Node (kvvmi.Status.NodeName)
    "AttachmentService"->>"AttachmentService": Check PV node affinity against Node
    alt PV not available on VM node
        "AttachmentService"->>"LifeCycleHandler": Return false
        "LifeCycleHandler"->>"User": Report error: DeviceNotAvailableOnNode
    else PV available on VM node
        "AttachmentService"->>"LifeCycleHandler": Return true
        "LifeCycleHandler"->>"AttachmentService": HotPlugDisk(...)
    end

Class diagram for updated AttachmentService and LifeCycleHandler

classDiagram
    class AttachmentService {
        +GetPersistentVolumeClaim(ctx, ad)
        +GetPersistentVolume(ctx, pvName)
        +GetVirtualMachine(ctx, name, namespace)
        +GetKVVMI(ctx, vm)
        +IsPVAvailableOnVMNode(ctx, pvc, kvvmi)
    }
    class LifeCycleHandler {
        +Handle(ctx, vmbda)
        -attacher: AttachmentService
    }
    AttachmentService <.. LifeCycleHandler: uses

Class diagram for vmbdacondition with new DeviceNotAvailableOnNode reason

classDiagram
    class AttachedReason {
        +Conflict
        +DeviceNotAvailableOnNode
    }
    class DiskAttachmentCapacityAvailableReason {
        +CapacityAvailable
    }

File-Level Changes

Change	Details	Files
Implement PV node affinity check in AttachmentService	Add GetPersistentVolume to retrieve a PersistentVolume by name Add IsPVAvailableOnVMNode to validate PV.Spec.NodeAffinity against the VM’s node, including nil checks, fetching PV and Node, and matching via nodeaffinity.NewNodeSelector Import the nodeaffinity helper from k8s component-helpers	`images/virtualization-artifact/pkg/controller/service/attachment_service.go`
Fail VMBDA lifecycle when PV is unavailable on VM node	In life_cycle handler, fetch PVC and call IsPVAvailableOnVMNode before hot-plug Set vmbda.Status.Phase to BlockDeviceAttachmentPhaseFailed with DeviceNotAvailableOnNode reason and a descriptive message	`images/virtualization-artifact/pkg/controller/vmbda/internal/life_cycle.go`
Introduce DeviceNotAvailableOnNode condition reason	Define new AttachedReason constant DeviceNotAvailableOnNode in condition.go	`api/core/v1alpha2/vmbdacondition/condition.go`

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deckhouse-BOaTswain · 2025-10-10T12:16:51Z