resources.cpu and resources.sockets are typed as quantities, but they land in domain.cpu.cores and domain.cpu.sockets, which KubeVirt declares as uint32. The chart cast them with int64, which turns 500m, 1.5 or 1e1 into 0 without an error, and KubeVirt boots a zero core count as one core. The user asked for half a core and got a one-core VM with nothing reporting it. The raw spelling is now decoded as YAML, the way an integer field reads it, and the render stops unless the result is a positive whole number that fits in uint32. A leading zero is refused, because YAML reads 010 as octal 8. The check keys on presence rather than truthiness, so an unquoted 0 is refused instead of being read as unset. Memory gets the same presence check. A quoted "0" was truthy and rendered requests.memory: "0", while an unquoted 0 was falsy and dropped, so one quantity took two paths. A zero or negative amount now stops the render in both spellings. BREAKING CHANGE: values that used to render now either fail or render differently. A cpu or sockets that does not decode to a plain whole number within uint32 (a millicore, suffixed such as 1k, fractional, zero, negative or leading-zero value), and a zero or negative memory, fail the next upgrade of the release until the value is fixed. This includes cpu or sockets set on its own beside an instanceType, which used to be ignored whatever it held. A spelling that the int64 cast truncated to 0 but that YAML decodes to a whole number, such as the exponent 1e1 or the trailing dot 2., used to boot one core and now sizes the VM with the count it spells, so such a VM changes size on upgrade. Assisted-by: LLM Signed-off-by: Aleksei Sviridkin <f@lex.la>
Virtual Machine
A Virtual Machine (VM) simulates computer hardware, enabling various operating systems and applications to run in an isolated environment.
Deployment Details
The virtual machine is managed and hosted through KubeVirt, allowing you to harness the benefits of virtualization within your Kubernetes ecosystem.
- Docs: KubeVirt User Guide
- GitHub: KubeVirt Repository
Accessing virtual machine
You can access the virtual machine using the virtctl tool:
To access the serial console:
virtctl console <vm>
To access the VM using VNC:
virtctl vnc <vm>
To SSH into the VM:
virtctl ssh <user>@<vm>
Parameters
Common parameters
| Name | Description | Type | Value |
|---|---|---|---|
external |
Enable external access from outside the cluster. | bool |
false |
externalMethod |
Method to pass through traffic to the VM. | string |
PortList |
externalPorts |
Ports to forward from outside the cluster. | []int |
[22] |
externalAllowICMP |
Whether to accept ICMP traffic to the VM in PortList mode (preserves ping and PMTU discovery). No effect in WholeIP mode. Default true so ping behaves as users expect even when port filtering is in effect. | bool |
true |
runStrategy |
Requested running state of the VirtualMachineInstance | string |
Always |
instanceType |
Virtual Machine instance type. Ignored when resources sizes the VM, which needs whole-number cpu and sockets plus memory; the whole type is dropped then, so any dedicated CPU placement, hugepages, NUMA or realtime settings it carries go with it. While this field is set, a resources block that sizes only part of the VM is rejected outright instead of ignored, so complete it or clear it. |
string |
u1.medium |
instanceProfile |
Virtual Machine preferences profile. | string |
ubuntu |
disks |
List of disks to attach. | []object |
[] |
disks[i].name |
Disk name. | string |
"" |
disks[i].bus |
Disk bus type (e.g. "sata"). | string |
"" |
networks |
Networks to attach the VM to. | []object |
[] |
networks[i].name |
Network attachment name. | string |
"" |
subnets |
Deprecated: use networks instead. | []object |
[] |
subnets[i].name |
Network attachment name. | string |
"" |
gpus |
List of GPUs to attach (NVIDIA driver requires at least 4 GiB RAM). | []object |
[] |
gpus[i].name |
The name of the GPU resource to attach. | string |
"" |
cpuModel |
Model specifies the CPU model inside the VMI. List of available models https://github.com/libvirt/libvirt/tree/master/src/cpu_map | string |
"" |
firmware |
Firmware and boot configuration (UEFI/BIOS selection, Secure Boot, persistent EFI NVRAM). | object |
{} |
firmware.bootloader |
Bootloader to boot the VM with: "uefi" (OVMF) or "bios" (SeaBIOS). Empty inherits the instanceProfile default. | string |
"" |
firmware.secureBoot |
Enable UEFI Secure Boot. Only applies when bootloader is "uefi". | bool |
false |
firmware.efiPersistent |
Persist EFI NVRAM (e.g. enrolled Secure Boot keys, such as an updated Microsoft UEFI CA) across reboots. Only applies when bootloader is "uefi". On default RWO storage the VM is node-pinned (no live-migration). | bool |
false |
resources |
Resource configuration for the virtual machine. Set whole-number cpu and sockets together with memory to size the VM directly, which overrides instanceType. Alongside an instanceType, a block that sizes only part of the VM is rejected; a whole-number cpu or sockets on its own sizes nothing and is ignored. |
object |
{} |
resources.cpu |
Number of CPU cores allocated, as a positive whole number such as 2. Millicore and fractional quantities are rejected at render time, because the value becomes the VM's integer domain.cpu.cores. |
quantity |
"" |
resources.memory |
Amount of memory allocated, as a positive quantity such as 8Gi. |
quantity |
"" |
resources.sockets |
Number of CPU sockets (vCPU topology), as a positive whole number such as 1. Millicore and fractional quantities are rejected at render time, because the value becomes the VM's integer domain.cpu.sockets. |
quantity |
"" |
sshKeys |
List of SSH public keys for authentication. | []string |
[] |
cloudInit |
Cloud-init user data. | string |
"" |
cloudInitSeed |
Seed string to generate SMBIOS UUID for the VM. | string |
"" |
U Series
The U Series is quite neutral and provides resources for general purpose applications.
U is the abbreviation for "Universal", hinting at the universal attitude towards workloads.
VMs of instance types will share physical CPU cores on a time-slice basis with other VMs.
U Series Characteristics
Specific characteristics of this series are:
- Burstable CPU performance - The workload has a baseline compute performance but is permitted to burst beyond this baseline, if excess compute resources are available.
- vCPU-To-Memory Ratio (1:4) - A vCPU-to-Memory ratio of 1:4, for less noise per node.
O Series
The O Series is based on the U Series, with the only difference being that memory is overcommitted.
O is the abbreviation for "Overcommitted".
UO Series Characteristics
Specific characteristics of this series are:
- Burstable CPU performance - The workload has a baseline compute performance but is permitted to burst beyond this baseline, if excess compute resources are available.
- Overcommitted Memory - Memory is over-committed in order to achieve a higher workload density.
- vCPU-To-Memory Ratio (1:4) - A vCPU-to-Memory ratio of 1:4, for less noise per node.
CX Series
The CX Series provides exclusive compute resources for compute intensive applications.
CX is the abbreviation of "Compute Exclusive".
The exclusive resources are given to the compute threads of the VM. In order to ensure this, some additional cores (depending on the number of disks and NICs) will be requested to offload the IO threading from cores dedicated to the workload. In addition, in this series, the NUMA topology of the used cores is provided to the VM.
CX Series Characteristics
Specific characteristics of this series are:
- Hugepages - Hugepages are used in order to improve memory performance.
- Dedicated CPU - Physical cores are exclusively assigned to every vCPU in order to provide fixed and high compute guarantees to the workload.
- Isolated emulator threads - Hypervisor emulator threads are isolated from the vCPUs in order to reduce emaulation related impact on the workload.
- vNUMA - Physical NUMA topology is reflected in the guest in order to optimize guest sided cache utilization.
- vCPU-To-Memory Ratio (1:2) - A vCPU-to-Memory ratio of 1:2.
M Series
The M Series provides resources for memory intensive applications.
M is the abbreviation of "Memory".
M Series Characteristics
Specific characteristics of this series are:
- Hugepages - Hugepages are used in order to improve memory performance.
- Burstable CPU performance - The workload has a baseline compute performance but is permitted to burst beyond this baseline, if excess compute resources are available.
- vCPU-To-Memory Ratio (1:8) - A vCPU-to-Memory ratio of 1:8, for much less noise per node.
RT Series
The RT Series provides resources for realtime applications, like Oslat.
RT is the abbreviation for "realtime".
This series of instance types requires nodes capable of running realtime applications.
RT Series Characteristics
Specific characteristics of this series are:
- Hugepages - Hugepages are used in order to improve memory performance.
- Dedicated CPU - Physical cores are exclusively assigned to every vCPU in order to provide fixed and high compute guarantees to the workload.
- Isolated emulator threads - Hypervisor emulator threads are isolated from the vCPUs in order to reduce emaulation related impact on the workload.
- vCPU-To-Memory Ratio (1:4) - A vCPU-to-Memory ratio of 1:4 starting from the medium size.
Development
To get started with customizing or creating your own instancetypes and preferences see DEVELOPMENT.md.
Resources
The following instancetype resources are provided by Cozystack:
| Name | vCPUs | Memory |
|---|---|---|
| cx1.2xlarge | 8 | 16Gi |
| cx1.2xlarge1gi | 8 | 16Gi |
| cx1.4xlarge | 16 | 32Gi |
| cx1.4xlarge1gi | 16 | 32Gi |
| cx1.8xlarge | 32 | 64Gi |
| cx1.8xlarge1gi | 32 | 64Gi |
| cx1.large | 2 | 4Gi |
| cx1.large1gi | 2 | 4Gi |
| cx1.medium | 1 | 2Gi |
| cx1.medium1gi | 1 | 2Gi |
| cx1.xlarge | 4 | 8Gi |
| cx1.xlarge1gi | 4 | 8Gi |
| d1.2xlarge | 8 | 32Gi |
| d1.2xmedium | 2 | 4Gi |
| d1.4xlarge | 16 | 64Gi |
| d1.8xlarge | 32 | 128Gi |
| d1.large | 2 | 8Gi |
| d1.medium | 1 | 4Gi |
| d1.micro | 1 | 1Gi |
| d1.nano | 1 | 512Mi |
| d1.small | 1 | 2Gi |
| d1.xlarge | 4 | 16Gi |
| gn1.2xlarge | 8 | 32Gi |
| gn1.4xlarge | 16 | 64Gi |
| gn1.8xlarge | 32 | 128Gi |
| gn1.xlarge | 4 | 16Gi |
| m1.2xlarge | 8 | 64Gi |
| m1.2xlarge1gi | 8 | 64Gi |
| m1.4xlarge | 16 | 128Gi |
| m1.4xlarge1gi | 16 | 128Gi |
| m1.8xlarge | 32 | 256Gi |
| m1.8xlarge1gi | 32 | 256Gi |
| m1.large | 2 | 16Gi |
| m1.large1gi | 2 | 16Gi |
| m1.xlarge | 4 | 32Gi |
| m1.xlarge1gi | 4 | 32Gi |
| n1.2xlarge | 16 | 32Gi |
| n1.4xlarge | 32 | 64Gi |
| n1.8xlarge | 64 | 128Gi |
| n1.large | 4 | 8Gi |
| n1.medium | 4 | 4Gi |
| n1.xlarge | 8 | 16Gi |
| o1.2xlarge | 8 | 32Gi |
| o1.4xlarge | 16 | 64Gi |
| o1.8xlarge | 32 | 128Gi |
| o1.large | 2 | 8Gi |
| o1.medium | 1 | 4Gi |
| o1.micro | 1 | 1Gi |
| o1.nano | 1 | 512Mi |
| o1.small | 1 | 2Gi |
| o1.xlarge | 4 | 16Gi |
| rt1.2xlarge | 8 | 32Gi |
| rt1.4xlarge | 16 | 64Gi |
| rt1.8xlarge | 32 | 128Gi |
| rt1.large | 2 | 8Gi |
| rt1.medium | 1 | 4Gi |
| rt1.micro | 1 | 1Gi |
| rt1.small | 1 | 2Gi |
| rt1.xlarge | 4 | 16Gi |
| u1.2xlarge | 8 | 32Gi |
| u1.2xmedium | 2 | 4Gi |
| u1.4xlarge | 16 | 64Gi |
| u1.8xlarge | 32 | 128Gi |
| u1.large | 2 | 8Gi |
| u1.medium | 1 | 4Gi |
| u1.micro | 1 | 1Gi |
| u1.nano | 1 | 512Mi |
| u1.small | 1 | 2Gi |
| u1.xlarge | 4 | 16Gi |
The following preference resources are provided by Cozystack:
| Name | Guest OS |
|---|---|
| alpine | Alpine |
| centos.stream10 | CentOS Stream 10 |
| centos.stream10.desktop | CentOS Stream 10 |
| centos.stream9 | CentOS Stream 9 |
| centos.stream9.desktop | CentOS Stream 9 |
| centos.stream9.dpdk | CentOS Stream 9 |
| cirros | Cirros |
| debian | Debian |
| fedora | Fedora (amd64) |
| fedora.arm64 | Fedora (arm64) |
| fedora.s390x | Fedora (s390x) |
| legacy | Legacy Guest |
| linux | Linux Guest |
| linux.efi | Linux EFI Guest |
| linux.virtiotransitional | Linux Virtio Transitional Guest |
| opensuse.leap | OpenSUSE Leap |
| opensuse.tumbleweed | OpenSUSE Tumbleweed |
| oraclelinux | Oracle Linux |
| rhel.10 | Red Hat Enterprise Linux 10 (amd64) |
| rhel.10.arm64 | Red Hat Enterprise Linux 10 (arm64) |
| rhel.10.s390x | Red Hat Enterprise Linux 10 (s390x) |
| rhel.7 | Red Hat Enterprise Linux 7 |
| rhel.7.desktop | Red Hat Enterprise Linux 7 |
| rhel.8 | Red Hat Enterprise Linux 8 |
| rhel.8.desktop | Red Hat Enterprise Linux 8 |
| rhel.8.dpdk | Red Hat Enterprise Linux 8 |
| rhel.9 | Red Hat Enterprise Linux 9 (amd64) |
| rhel.9.arm64 | Red Hat Enterprise Linux 9 (arm64) |
| rhel.9.desktop | Red Hat Enterprise Linux 9 Desktop (amd64) |
| rhel.9.dpdk | Red Hat Enterprise Linux 9 DPDK (amd64) |
| rhel.9.realtime | Red Hat Enterprise Linux 9 Realtime (amd64) |
| rhel.9.s390x | Red Hat Enterprise Linux 9 (s390x) |
| sles | SUSE Linux Enterprise Server |
| ubuntu | Ubuntu |
| windows.10 | Microsoft Windows 10 |
| windows.10.virtio | Microsoft Windows 10 (virtio) |
| windows.11 | Microsoft Windows 11 |
| windows.11.virtio | Microsoft Windows 11 (virtio) |
| windows.2k12 | Microsoft Windows Server 2012/2012 R2 |
| windows.2k12.virtio | Microsoft Windows Server 2012/2012 R2 (virtio) |
| windows.2k16 | Microsoft Windows Server 2016 |
| windows.2k16.virtio | Microsoft Windows Server 2016 (virtio) |
| windows.2k19 | Microsoft Windows Server 2019 |
| windows.2k19.virtio | Microsoft Windows Server 2019 (virtio) |
| windows.2k22 | Microsoft Windows Server 2022 |
| windows.2k22.virtio | Microsoft Windows Server 2022 (virtio) |
| windows.2k25 | Microsoft Windows Server 2025 |
| windows.2k25.virtio | Microsoft Windows Server 2025 (virtio) |
| windows.2k3 | Microsoft Windows Server 2003 |
| windows.2k8 | Microsoft Windows Server 2008/2008 R2 |
| windows.2k8.virtio | Microsoft Windows Server 2008/2008 R2 (virtio) |
| windows.7 | Microsoft Windows 7 |
| windows.7.virtio | Microsoft Windows 7 (virtio) |
| windows.xp | Microsoft Windows XP |