Service objects

Once the VirtualMachineInstance is started, in order to connect to a VirtualMachineInstance, you can create a Service object for a VirtualMachineInstance. Currently, three types of service are supported: ClusterIP, NodePort and LoadBalancer. The default type is ClusterIP.

Note: Labels on a VirtualMachineInstance are passed through to the pod, so simply add your labels for service creation to the VirtualMachineInstance. From there on it works like exposing any other k8s resource, by referencing these labels in a service.

Expose VirtualMachineInstance as a ClusterIP Service

Give a VirtualMachineInstance with the label special: key:

  1. apiVersion: kubevirt.io/v1alpha3
  2. kind: VirtualMachineInstance
  3. metadata:
  4.   name: vmi-ephemeral
  5.   labels:
  6.     special: key
  7. spec:
  8.   domain:
  9.     devices:
  10.       disks:
  11.       - disk:
  12.           bus: virtio
  13.         name: containerdisk
  14.     resources:
  15.       requests:
  16.         memory: 64M
  17.   volumes:
  18.   - name: containerdisk
  19.     containerDisk:
  20.       image: kubevirt/cirros-registry-disk-demo:latest

we can expose its SSH port (22) by creating a ClusterIP service:

  1. apiVersion: v1
  2. kind: Service
  3. metadata:
  4.   name: vmiservice
  5. spec:
  6.   ports:
  7.   - port: 27017
  8.     protocol: TCP
  9.     targetPort: 22
  10.   selector:
  11.     special: key
  12.   type: ClusterIP

You just need to create this ClusterIP service by using kubectl:

  1. $ kubectl create -f vmiservice.yaml

Alternatively, the VirtualMachineInstance could be exposed using the virtctl command:

  1. $ virtctl expose virtualmachineinstance vmi-ephemeral --name vmiservice --port 27017 --target-port 22

Notes: * If --target-port is not set, it will be take the same value as --port * The cluster IP is usually allocated automatically, but it may also be forced into a value using the --cluster-ip flag (assuming value is in the valid range and not taken)

Query the service object:

  1. $ kubectl get service
  2. NAME        TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)     AGE
  3. vmiservice   ClusterIP   172.30.3.149   <none>        27017/TCP   2m

You can connect to the VirtualMachineInstance by service IP and service port inside the cluster network:

  1. $ ssh cirros@172.30.3.149 -p 27017

Expose VirtualMachineInstance as a NodePort Service

Expose the SSH port (22) of a VirtualMachineInstance running on KubeVirt by creating a NodePort service:

  1. apiVersion: v1
  2. kind: Service
  3. metadata:
  4.   name: nodeport
  5. spec:
  6.   externalTrafficPolicy: Cluster
  7.   ports:
  8.   - name: nodeport
  9.     nodePort: 30000
  10.     port: 27017
  11.     protocol: TCP
  12.     targetPort: 22
  13.   selector:
  14.     special: key
  15.   type: NodePort

You just need to create this NodePort service by using kubectl:

  1. $ kubectl -f nodeport.yaml

Alternatively, the VirtualMachineInstance could be exposed using the virtctl command:

  1. $ virtctl expose virtualmachineinstance vmi-ephemeral --name nodeport --type NodePort --port 27017 --target-port 22 --node-port 30000

Notes: * If --node-port is not set, its value will be allocated dynamically (in the range above 30000) * If the --node-port value is set, it must be unique across all services

The service can be listed by querying for the service objects:

  1. $ kubectl get service
  2. NAME           TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)           AGE
  3. nodeport       NodePort   172.30.232.73   <none>        27017:30000/TCP   5m

Connect to the VirtualMachineInstance by using a node IP and node port outside the cluster network:

  1. $ ssh cirros@$NODE_IP -p 30000

Expose VirtualMachineInstance as a LoadBalancer Service

Expose the RDP port (3389) of a VirtualMachineInstance running on KubeVirt by creating LoadBalancer service. Here is an example:

  1. apiVersion: v1
  2. kind: Service
  3. metadata:
  4.   name: lbsvc
  5. spec:
  6.   externalTrafficPolicy: Cluster
  7.   ports:
  8.   - port: 27017
  9.     protocol: TCP
  10.     targetPort: 3389
  11.   selector:
  12.     special: key
  13.   type: LoadBalancer

You could create this LoadBalancer service by using kubectl:

  1. $ kubectl -f lbsvc.yaml

Alternatively, the VirtualMachineInstance could be exposed using the virtctl command:

  1. $ virtctl expose virtualmachineinstance vmi-ephemeral --name lbsvc --type LoadBalancer --port 27017 --target-port 3389

Note that the external IP of the service could be forced to a value using the --external-ip flag (no validation is performed on this value).

The service can be listed by querying for the service objects:

  1. $ kubectl get svc
  2. NAME      TYPE           CLUSTER-IP       EXTERNAL-IP                   PORT(S)           AGE
  3. lbsvc     LoadBalancer   172.30.27.5      172.29.10.235,172.29.10.235   27017:31829/TCP   5s

Use vinagre client to connect your VirtualMachineInstance by using the public IP and port.

Note that here the external port here (31829) was dynamically allocated.