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Kubevirt 实践 #

简介 #

Kubevirt 是 Redhat 开源的以容器方式运行虚拟机的项目,以 k8s add-on 方式,利用 k8s CRD 为增加资源类型 VirtualMachineInstance(VMI), 使用容器的 image registry 去创建虚拟机并提供 VM 生命周期管理。 CRD 的方式使得 kubevirt 对虚拟机的管理不局限于 pod 管理接口,但是也无法使用 pod 的 RS DS Deployment 等管理能力,也意味着 kubevirt 如果想要利用 pod 管理能力,要自主去实现,目前 kubevirt 实现了类似 RS 的功能。 kubevirt 目前支持的 runtime 是 docker 和 runc。

安装 #

  1. 部署 K8s 资源
# 最新版本
export KUBEVIRT_VERSION=$(curl -s https://api.github.com/repos/kubevirt/kubevirt/releases/latest | jq -r .tag_name)
echo $KUBEVIRT_VERSION

# 安装 CRD
kubectl create -f https://github.com/kubevirt/kubevirt/releases/download/${KUBEVIRT_VERSION}/kubevirt-cr.yaml

# 安装控制器
kubectl create -f https://github.com/kubevirt/kubevirt/releases/download/${KUBEVIRT_VERSION}/kubevirt-operator.yaml
  1. 安装 virtctl 工具
wget -O virtctl https://github.com/kubevirt/kubevirt/releases/download/${KUBEVIRT_VERSION}/virtctl-${KUBEVIRT_VERSION}-linux-amd64

chmod +x virtctl
mv virtctl /usr/local/bin
  1. 检查资源状态
# 需要等待所有 Pod 处于 Running 状态
kubectl get pods -n kubevirt

# 需要等待 kubevirt 处于 Deployed 状态
kubectl -n kubevirt get kubevirt
  1. 卸载

卸载首先需要删除 CRD,然后卸载控制器。

# 0、获取当前 Kubevirt 版本
export KUBEVIRT_VERSION=$(kubectl get kubevirts.kubevirt.io -n kubevirt kubevirt -o=jsonpath='{.status.observedKubeVirtVersion}')

# 1、删除 CRD
kubectl delete -f https://github.com/kubevirt/kubevirt/releases/download/${KUBEVIRT_VERSION}/kubevirt-cr.yaml

# 2、卸载控制器
kubectl delete -f kubectl create -f https://github.com/kubevirt/kubevirt/releases/download/${KUBEVIRT_VERSION}/kubevirt-operator.yaml

概念 #

  • 虚拟机(VirtualMachine)
  • 虚拟机实例(VirtualMachineInstance)

创建虚拟机 #

现在你可以像创建其他任何 K8s 资源一样,声明虚拟机资源然后创建了,如下:

apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
  name: testvm
spec:
  running: false
  template:
    metadata:
      labels:
        kubevirt.io/size: small
        kubevirt.io/domain: testvm
    spec:
      domain:
        devices:
          disks:
            - name: containerdisk
              disk:
                bus: virtio
            - name: cloudinitdisk
              disk:
                bus: virtio
          interfaces:
          - name: default
            masquerade: {}
        resources:
          requests:
            memory: 64M
      networks:
      - name: default
        pod: {}
      volumes:
        - name: containerdisk
          containerDisk:
            image: quay.io/kubevirt/cirros-container-disk-demo
        - name: cloudinitdisk
          cloudInitNoCloud:
            userDataBase64: SGkuXG4=

创建虚拟机:

kubectl apply -f testvm.yaml

查看虚拟机状态,虚拟机应该处于未运行的状态:

# kubectl get vms

kubectl get vms -o yaml testvm | grep -E 'running:.*|$'

运行虚拟机 #

使用 virtctl start 命令运行虚拟机:

virtual start testvm

注意:

如果遇到 virtctl start testvm dial tcp 127.0.0.1:8080: connect: connection refused问题,通过 kubectl proxy --port 8080 在本地代理 K8s apiserver 服务。

等待片刻,再次查看虚拟机状态,虚拟机应该处于未运行的状态:

kubectl get vms -o yaml testvm | grep -E 'running:.*|$'

kubectl get vmis

kubectl get vms 

访问虚拟机 #

使用 virtual console 命令访问虚拟机:

virtual console testvm

注意:

  • 使用镜像 quay.io/kubevirt/cirros-container-disk-demo 创建的虚拟机,默认账号密码:cirros/gocubsgo
  • 使用 ctrl+] 退出。

关闭虚拟机 #

使用 virtual stop 命令访问虚拟机:

virtual stop testvm

删除虚拟机:

kubectl delete vms testvm

磁盘访问 #

lun #

将卷以 lun 的方式公开给虚拟机。

pvc

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: lun-pvc
  namespace: default
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: longhorn
  volumeMode: Filesystem

vm

apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
  name: testvm
spec:
  running: false
  template:
    metadata:
      labels:
        kubevirt.io/size: small
        kubevirt.io/domain: testvm
    spec:
      domain:
        devices:
          disks:
            - name: containerdisk
              disk:
                bus: virtio
            - name: cloudinitdisk
              disk:
                bus: virtio
            - name: lundisk
              lun: {}
          interfaces:
          - name: default
            masquerade: {}
        resources:
          requests:
            memory: 64M
      networks:
      - name: default
        pod: {}
      volumes:
        - name: containerdisk
          containerDisk:
            image: quay.io/kubevirt/cirros-container-disk-demo
        - name: cloudinitdisk
          cloudInitNoCloud:
            userDataBase64: SGkuXG4=
        - name: lundisk
          persistentVolumeClaim:
            claimName: lun-pvc

disk #

pvc:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: disk-pvc
  namespace: default
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: longhorn
  volumeMode: Filesystem

vm:

apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
  name: testvm
spec:
  running: false
  template:
    metadata:
      labels:
        kubevirt.io/size: small
        kubevirt.io/domain: testvm
    spec:
      domain:
        devices:
          disks:
            - name: containerdisk
              disk:
                bus: virtio
            - name: cloudinitdisk
              disk:
                bus: virtio
            - name: disk-pvc
              disk: 
                bus: virtio
          interfaces:
          - name: default
            masquerade: {}
        resources:
          requests:
            memory: 64M
      networks:
      - name: default
        pod: {}
      volumes:
        - name: containerdisk
          containerDisk:
            image: quay.io/kubevirt/cirros-container-disk-demo
        - name: cloudinitdisk
          cloudInitNoCloud:
            userDataBase64: SGkuXG4=
        - name: disk-pvc
          persistentVolumeClaim:
            claimName: disk-pvc

cdrom #

将卷以 cdrom 驱动器的方式公开给虚拟机。默认情况下只读,可以通过 readonly: false 设置为可写。

pvc:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: cdrom-pvc
  namespace: default
spec:
  accessModes:
  - ReadWriteOnce
  resources:
    requests:
      storage: 1Gi
  storageClassName: longhorn
  volumeMode: Filesystem

vm:

apiVersion: kubevirt.io/v1
kind: VirtualMachine
metadata:
  name: testvm
spec:
  running: false
  template:
    metadata:
      labels:
        kubevirt.io/size: small
        kubevirt.io/domain: testvm
    spec:
      domain:
        devices:
          disks:
            - name: containerdisk
              disk:
                bus: virtio
            - name: cloudinitdisk
              disk:
                bus: virtio
            - name: disk-pvc
              cdrom:
                readonly: false
                bus: sata
          interfaces:
          - name: default
            masquerade: {}
        resources:
          requests:
            memory: 64M
      networks:
      - name: default
        pod: {}
      volumes:
        - name: containerdisk
          containerDisk:
            image: quay.io/kubevirt/cirros-container-disk-demo
        - name: cloudinitdisk
          cloudInitNoCloud:
            userDataBase64: SGkuXG4=
        - name: cdrom-pvc
          persistentVolumeClaim:
            claimName: cdrom-pvc

排错 #

  1. 使用 virtctl 工具运行虚拟机时,遇到 virtctl start testvm dial tcp 127.0.0.1:8080: connect: connection refused 错误:

解决方法:本地代理 K8s apiserver 服务。

kubectl proxy --port 8080

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