add comments for instanceID usage

Author: wanyufe

pkg/cloud/instance.go

@@ -41,6 +41,7 @@ type VMIface interface {
 // Set infrastructure spec and status from the CloudStack API's virtual machine metrics type.
 func setMachineDataFromVMMetrics(vmResponse *cloudstack.VirtualMachinesMetric, csMachine *infrav1.CloudStackMachine) {
 	csMachine.Spec.ProviderID = pointer.StringPtr(fmt.Sprintf("cloudstack:///%s", vmResponse.Id))
+	// InstanceID is later used as required parameter to destroy VM.
 	csMachine.Spec.InstanceID = pointer.StringPtr(vmResponse.Id)
 	csMachine.Status.Addresses = []corev1.NodeAddress{{Type: corev1.NodeInternalIP, Address: vmResponse.Ipaddress}}
 	newInstanceState := vmResponse.State