As I alluded to in my previous demo post we have some exciting new features currently under development concerning instance types and preferences. This post introduces one of these, the ability for KubeVirt to infer the default instance type and preference of a VirtualMachine from a suggested Volume.
Current Design
The current design document PR is listed below:
design-proposals: Default instance types inferred from volumes https://github.com/kubevirt/community/pull/190
The tl;dr being that the {Instancetype,Preference}Matchers will be extended with an inferFromVolume attribute that will reference the name of a Volume associatied with the VirtualMachine. This Volume will then be used to infer defaults by looking for the following annotations:
instancetype.kubevirt.io/defaultInstancetypeinstancetype.kubevirt.io/defaultInstancetypeKind(Defaults toVirtualMachineClusterInstancetype)instancetype.kubevirt.io/defaultPreferenceinstancetype.kubevirt.io/defaultPreferenceKind(Defaults toVirtualMachineClusterPreference)
Initially only PVC and DataVolume derived Volumes will be supported but this will likely be extended to anything with annotations, such as Containers.
Feedback is welcome in the design review document if you have any!
Demo
This demo is based on some work in progress code posted below:
WIP - Introduce support for default instance type and preference PVC annotations https://github.com/kubevirt/kubevirt/pull/8480
The demo script, resource definitions and asciinema recording can be found below:
https://github.com/lyarwood/demos/tree/main/kubevirt/instancetypes/4-infer-default-instancetypes