MicroVM kernel and OS

The kernel binary and operating system for MicroVMs are supplied via OCI images.

They are pulled and mounted by containerd.

Liquid Metal supplies images for use with MicroVM clusters, see [Supported Images][#supported-images] below

Using images

CAPMVM

Set the following variables before generating your manifest via clusterctl.

export MVM_ROOT_IMAGE=REGISTRY/ORG/REPO:1.21.8
export MVM_KERNEL_IMAGE=REGISTRY/ORG/REPO:5.10.77
export MVM_KERNEL_MODULES_IMAGE=REGISTRY/ORG/REPO:5.10.77

Or edit the manifest directly for each MicrovmMachineTemplate.

Manifest changes

...
---
apiVersion: infrastructure.cluster.x-k8s.io/v1alpha1
kind: MicrovmMachineTemplate
spec:
  template:
    spec:
      kernel:
        filename: boot/vmlinux # make sure this matches where you left the kernel binary
        image: KERNEL_IMAGE
      volumes:
      - id: modules
        image: MODULES_IMAGE
        mountPoint: /lib/modules/VERSION # ensure this version matches the kernel and modules version
      rootVolume:
        id: root
        image: OS_IMAGE
...

Flintlock

If using another flintlock client to create MicroVMs directly, set the spec.root_volume.source.container_source, spec.kernel.image and spec.additional_volumes[0] options on the CreateMicroVMRequest call.

For example if using hammertime, edit the spec like so:

Spec example

{
    "root_volume": {
        "id": "root",
        "is_read_only": false,
        "source": {
          "container_source": OS_IMAGE
        }
    },
    "kernel": {
      "image": KERNEL_IMAGE,
      "filename": "boot/vmlinux", # make sure this matches where you left the kernel binary
      "add_network_config": true
    },
    "additional_volumes": [{
        "id": "modules",
        "is_read_only": false,
        "mount_point": "/lib/modules/VERSION", # ensure this version matches the kernel and modules version
        "source": {
          "container_source": MODULES_IMAGE
        }
    }]
}

Supported images

Kernel Binary:

• ghcr.io/weaveworks-liquidmetal/kernel-bin:5.10.77
• ghcr.io/weaveworks-liquidmetal/kernel-bin:4.19.215

Kernel Modules:

• ghcr.io/weaveworks-liquidmetal/kernel-modules:5.10.77
• ghcr.io/weaveworks-liquidmetal/kernel-modules:4.19.215

OS/Root Volume:

The tags here refer to the version of Kubernetes. The base OS is Ubuntu 20.04.

• ghcr.io/weaveworks-liquidmetal/capmvm-k8s-os:1.23.5
• ghcr.io/weaveworks-liquidmetal/capmvm-k8s-os:1.22.8
• ghcr.io/weaveworks-liquidmetal/capmvm-k8s-os:1.22.3
• ghcr.io/weaveworks-liquidmetal/capmvm-k8s-os:1.21.8

Older CAPMVM / Flintlock Versions

If you are using a CAPMVM <= v0.7.0 or Flintlock <= v0.4.0 the separate modules volume is not supported. Supply the following legacy images instead:

• Kernel: ghcr.io/weaveworks-liquidmetal/flintlock-kernel:X.X.X
• Root volume: ghcr.io/weaveworks-liquidmetal/capmvm-kubernetes:X.X.X

Experimental images

danger

These images are not guaranteed to work.

Kernel:

• ghcr.io/weaveworks-liquidmetal/flintlock-kernel-arm:5.10.77
• ghcr.io/weaveworks-liquidmetal/flintlock-kernel-arm:4.19.215

OS:

• ghcr.io/weaveworks-liquidmetal/capmvm-kubernetes-arm:1.23.5
• ghcr.io/weaveworks-liquidmetal/capmvm-kubernetes-arm:1.22.8
• ghcr.io/weaveworks-liquidmetal/capmvm-kubernetes-arm:1.22.3
• ghcr.io/weaveworks-liquidmetal/capmvm-kubernetes-arm:1.21.8

Build your own images

You can supply your own images if desired.

Our image builder can be found here if you would like to use it as a base.

info

Note that firecracker only documents support for 5.10 and 4.19 kernels.