virt-operator

virt-operator 是 KubeVirt 的安裝與生命週期管理元件，負責在 Kubernetes 叢集中部署、設定、升級所有其他 KubeVirt 元件。

職責概述

部署資訊

項目	值
部署型態	Kubernetes Deployment
副本數	≥ 2 (Leader Election)
監聽 Port	8186 (Metrics & Leader Election)
Namespace	kubevirt
Leader Election	使用 Kubernetes Lease (duration: 15s)

啟動方式

KubeVirt 的安裝分兩步：

# 步驟 1：部署 virt-operator (唯一需要手動部署的元件)
kubectl apply -f https://github.com/kubevirt/kubevirt/releases/latest/download/kubevirt-operator.yaml

# 步驟 2：建立 KubeVirt CR (觸發 virt-operator 部署其他元件)
kubectl apply -f https://github.com/kubevirt/kubevirt/releases/latest/download/kubevirt-cr.yaml

KubeVirt CR 詳解

apiVersion: kubevirt.io/v1
kind: KubeVirt
metadata:
  name: kubevirt
  namespace: kubevirt
spec:
  # 映像檔設定
  imageTag: "v1.x.x"
  imageRegistry: "quay.io/kubevirt"
  imagePullPolicy: IfNotPresent

  # 元件資源配置
  infra:
    replicas: 2           # virt-api, virt-controller 副本數
    nodePlacement:
      affinity: {}        # 節點親和性規則

  workloads:
    nodePlacement:
      tolerations: []     # virt-handler 的 toleration

  # VM 更新策略
  workloadUpdateStrategy:
    workloadUpdateMethods:
    - LiveMigrate         # 更新時用 Live Migration
    # - Evict             # 或者驅逐 VM

  # Feature Gates (功能開關)
  configuration:
    developerConfiguration:
      featureGates:
      - HotplugVolumes         # 開啟 volume 熱插拔
      - LiveMigration          # 開啟 live migration
      - Snapshot               # 開啟快照功能
      - CPUManager             # 開啟 CPU 固定
      - NUMA                   # 開啟 NUMA 拓撲
      - HypervStrictCheck      # Hyper-V 嚴格檢查

    # 網路設定
    network:
      defaultNetworkInterface: "masquerade"
      permitSlirpInterface: false

    # 儲存設定
    permittedHostDevices:
      pciHostDevices:
      - pciVendorSelector: "10DE:1DB6"  # NVIDIA GPU
        resourceName: "nvidia.com/GP100GL"

  # 憑證輪換
  certificateRotateStrategy:
    selfSigned:
      caRotateInterval: "168h"
      certRotateInterval: "24h"

  # OpenShift 監控整合
  monitorNamespace: "openshift-monitoring"
  monitorAccount: "prometheus-k8s"

virt-operator 產生的資源

Deployments & DaemonSets

// pkg/virt-operator/resource/generate/components/deployments.go
NewApiServerDeployment()       // virt-api
NewControllerDeployment()      // virt-controller
NewOperatorDeployment()        // virt-operator 自身
NewExportProxyDeployment()     // virt-exportproxy
NewSynchronizationControllerDeployment() // 同步控制器

// pkg/virt-operator/resource/generate/components/daemonsets.go
NewHandlerDaemonSet()          // virt-handler

RBAC 資源

rbac/
├── apiserver.go    → ServiceAccount, ClusterRole for virt-api
├── controller.go   → ServiceAccount, ClusterRole for virt-controller
├── handler.go      → ServiceAccount, ClusterRole for virt-handler
├── operator.go     → ClusterRole for virt-operator
└── exportproxy.go  → ServiceAccount, ClusterRole for export proxy

Webhook 設定

virt-operator 動態建立並維護以下 webhooks：

Mutating Webhooks（自動補齊預設值）：

• virtualmachines-mutate — VM spec 補齊
• virtualmachineinstances-mutate — VMI spec 補齊

Validating Webhooks（驗證正確性）：

• virtualmachines-validate — VM spec 驗證
• virtualmachineinstances-validate — VMI spec 驗證
• virtualmachinepresets-validate — Preset 驗證
• migration-validate — Migration 請求驗證
• 以及 Snapshot、Clone、Instancetype 等的 webhook

Rate Limiting 設定

// pkg/virt-operator/application.go
const (
    defaultPort = 8186
    defaultHost = "0.0.0.0"
    // 可透過環境變數調整
    EnvVirtOperatorClientQPS   = "VIRT_OPERATOR_CLIENT_QPS"
    EnvVirtOperatorClientBurst = "VIRT_OPERATOR_CLIENT_BURST"
)

// 預設值
DefaultVirtOperatorQPS   = 50
DefaultVirtOperatorBurst = 100

KubeVirt CR 狀態追蹤

status:
  phase: Deployed          # Deploying | Deployed | Deleting | Deleted
  observedKubeVirtVersion: "v1.x.x"
  targetKubeVirtVersion: "v1.x.x"
  observedDeploymentID: "xxxx"
  conditions:
  - type: Available
    status: "True"
    reason: AllComponentsReady
  - type: Progressing
    status: "False"
  - type: Degraded
    status: "False"

升級流程

當使用者更新 KubeVirt CR 的 imageTag 時：

重要原始碼位置

功能	路徑
主程式入口	cmd/virt-operator/main.go
Application 結構	pkg/virt-operator/application.go
KubeVirt 控制器	pkg/virt-operator/kubevirt.go
資源產生器	pkg/virt-operator/resource/generate/components/
RBAC 產生器	pkg/virt-operator/resource/generate/rbac/
Install Strategy	pkg/virt-operator/resource/apply/