kubevirt/common-instancetypes

A set of instance types and preferences to help create KubeVirt VirtualMachines.

Overview

Structure

The available instance types can be divided into two categories:

1. Workload agnostic - or general purpose
2. Workload specific

Workload agnostic instance types are a good starting point to run your workload. Once you know more about the requirements of your workload, you can start choosing a workload specific instance type.

The following diagram summarizes the available instance types and their use-cases:

graph TD

classDef grp fill:white,stroke:lightgray,color:gray
classDef series fill:lightyellow,stroke:lightgray
classDef instancetype fill:

wrklda(Workload agnostic)
wrklds(Workload specific)
class wrklda grp

wrklda:::grp --> Universal:::series
Universal([Universal]):::series --> u1:::instancetype

wrklda:::grp --> Overcommitted:::series
Overcommitted([Overcommitted]):::series --> o1:::instancetype

wrklds:::grp --> Computeexclusive:::series
Computeexclusive([Compute Exclusive]):::series --> cx1:::instancetype

wrklds:::grp --> GPUNVIDIA:::series
GPUNVIDIA([GPU NVIDIA]):::series --> gn1:::instancetype

wrklds:::grp --> Memory:::series
Memory([Memory]):::series --> m1:::instancetype

wrklds:::grp --> Network:::series
Network([Network]):::series --> n1:::instancetype

wrklds:::grp --> Realtime:::series
Realtime([Realtime]):::series --> rt1:::instancetype

Loading

Labels

Various labels are used to decorate objects provided by this project to help end users find the right resources for them. See docs/labels.md for more details.

Schema

Click in order to view the instance type names schema

instanceTypeName = seriesName , "." , size;

seriesName = ( class | vendorClass ) , version;

class = "u" | "o" | "cx" | "g" | "m" | "n" | "rt";
vendorClass = "g" , vendorHint;
vendorHint = "n" | "i" | "a";
version = "1";

size = "small" | "medium" | "large" | [( "2" | "4" | "8" )] , "xlarge";

Series

.	U	O	CX	GN	M	N	RT
Has GPUs				✓
Hugepages			✓		✓	✓	✓
Overcommitted Memory		✓
Dedicated CPU			✓			✓	✓
Burstable CPU performance	✓	✓		✓	✓
Isolated emulator threads			✓			✓	✓
vNUMA			✓				✓
vCPU-To-Memory Ratio	1:4	1:4	1:2	1:4	1:8	1:2	1:4

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.

GN Series

The GN Series provides instances types intended for VMs with NVIDIA GPU resources attached.

GN is the abbreviation of "GPU NVIDIA".

This series is intended to be used with VMs consuming GPUs provided by the NVIDIA GPU Operator which can be installed on Kubernetes and also is made available on OpenShift via OperatorHub.

GN Series Characteristics

Specific characteristics of this series are:

• Has GPUs - Has GPUs predefined.
• 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.

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.

N Series

The N Series provides resources for network intensive DPDK applications, like VNFs.

N is the abbreviation for "Network".

This series of instancetypes requires nodes capable of running DPDK workloads and being marked with the respective node-role.kubevirt.io/worker-dpdk label as such.

N 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 (1:2) - A vCPU-to-Memory ratio of 1:2.

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 (cluster-wide and namespaced) are provided by this project:

Name	vCPUs	Memory
cx1.2xlarge	8	16Gi
cx1.4xlarge	16	32Gi
cx1.8xlarge	32	64Gi
cx1.large	2	4Gi
cx1.medium	1	2Gi
cx1.xlarge	4	8Gi
gn1.2xlarge	8	32Gi
gn1.4xlarge	16	64Gi
gn1.8xlarge	32	128Gi
gn1.xlarge	4	16Gi
m1.2xlarge	8	64Gi
m1.4xlarge	16	128Gi
m1.8xlarge	32	256Gi
m1.large	2	16Gi
m1.xlarge	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 (cluster-wide and namespaced) are provided by this project:

Name	Guest OS
alpine	Alpine
centos.7	CentOS 7
centos.7.desktop	CentOS 7
centos.stream10	CentOS Stream 10
centos.stream10.desktop	CentOS Stream 10
centos.stream8	CentOS Stream 8
centos.stream8.desktop	CentOS Stream 8
centos.stream8.dpdk	CentOS Stream 8
centos.stream9	CentOS Stream 9
centos.stream9.desktop	CentOS Stream 9
centos.stream9.dpdk	CentOS Stream 9
cirros	Cirros
fedora	Fedora (amd64)
fedora.arm64	Fedora (arm64)
opensuse.leap	OpenSUSE Leap
opensuse.tumbleweed	OpenSUSE Tumbleweed
rhel.10	Red Hat Enterprise Linux 10 Beta (amd64)
rhel.10.arm64	Red Hat Enterprise Linux 10 Beta (arm64)
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)
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.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)