Exploring KubeVirt – Rebooting VMs through kubeinvaders – part 2

I returned a few hours ago from Naples after my usual Christmas trip, and I decided to write an article about the progress made with KubeVirt, particularly the integration of KubeVirt into KubeInvaders. Essentially, I want to reboot virtual machines while playing Space Invaders, just like I currently do with regular pods.

First of all, I needed to check the KubeVirt API, which I found here: https://kubevirt.io/api-reference/

For my purpose I need https://kubevirt.io/api-reference/v1.4.0/operations.html#_v1restart

PUT /apis/subresources.kubevirt.io/v1/namespaces/{namespace}/virtualmachines/{name}/restart
Description
Restart a VirtualMachine object.

The other API function I need is the list of virtual machines for a namespace, in order to discover all the virtual machines during the game.

GET /apis/kubevirt.io/v1/namespaces/{namespace}/virtualmachines
Description
Get a list of VirtualMachine objects.

Then, I needed to create a role to allow my service account to reboot the VMs.

I like Kubernetes RBAC, as it allows me to grant permissions specifically for rebooting VMs. Below is the ClusterRole:

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  namespace: default
  name: kubevirt-vm-restart-role
rules:
- apiGroups: ["subresources.kubevirt.io"]
  resources: ["virtualmachines/restart"]
  verbs: ["update"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: kubevirt-vm-restart-binding
  namespace: default
subjects:
- kind: ServiceAccount
  name: kubeinvaders
  namespace: kubeinvaders
roleRef:
  kind: ClusterRole
  name: kubevirt-vm-restart-role
  apiGroup: rbac.authorization.k8s.io

Because the game will now support both pods and VMs, I decided to add a legend to represent the different statuses of the objects I want to observe and add some special keys for set the game for discovery virtual machines

# Controls and Options

h => Enable or disable help
s => Enable or disable shuffle for aliens
n => Change the namespace
p => Display pods switch
c => Display nodes switch
v => Display virtual machines (kubevirt) switch

Obviously, it is important to press ‘p’ to disable the discovery of the pods in order to avoid killing the virt-launcher pod and to focus only on the VMs.

I have prepared two VMs in my first post related to KubeVirt that I used for testing this feature. During the test, I observed this command.

[root@node1 ~]# kubectl get vms
NAME            AGE   STATUS    READY
ubuntu-bionic   23d   Running   True
vm-d9f5z        23d   Stopped   False

I recorded this short video where I have a shell on the right in which I observe the list and status of the VMs in the default namespace. I position myself on the game console, removing the pods from the visualization (by pressing the “p” key) and enabling the virtual machines (by pressing the “v” key). Then, I launched some missiles towards the alien representing my running VM called “ubuntu-bionic,” and I saw its state change (i.e., the color of the alien changes).

Naturally, performing chaos engineering on the pods makes much more sense, but I believe setting up resilience tests for virtual machines in Kubernetes also makes sense to observe the reboot and scheduling speed, as well as to test distributed systems migrated to Kubernetes.

I released this new feature that you can use by installing k-inv through Helm.

helm repo add kubeinvaders https://lucky-sideburn.github.io/helm-charts/
helm repo update

kubectl create namespace kubeinvaders

# With ingress and TLS enabled
helm install --set-string config.target_namespace="default\,namespace1\,namespace2" --set ingress.enabled=true --set ingress.hostName=kubeinvaders.local --set deployment.image.tag=latest -n kubeinvaders kubeinvaders kubeinvaders/kubeinvaders --set ingress.tls_enabled=true

Thank you for your attention!