PaaS Cloud Technical Reference VM Instance Types and Profiles Cozystack provides predefined instance types (hardware templates) and instance profiles (guest OS preferences) for KubeVirt virtual machines. Using these abstractions simplifies VM creation and ensures consistent performance characteristics.
Instance types define CPU, memory, and performance policies for a VM. They are provided by Cozystack as KubeVirt instancetype resources.
Series Abbreviation Use Case CPU Memory Ratio U Universal General-purpose applications Burstable 1:4 O Overcommitted Higher density, memory overcommitted Burstable 1:4 CX Compute Exclusive Compute-intensive workloads Dedicated 1:2 M Memory Memory-intensive applications Burstable + Hugepages 1:8 RT Realtime Realtime / low-latency workloads Dedicated + Hugepages 1:4
Burstable CPU — Baseline performance with burst capability.vCPU-to-Memory Ratio 1:4 — Balanced for most workloads.
Name vCPUs Memory u1.nano 1 512Mi u1.micro 1 1Gi u1.small 1 2Gi u1.medium 1 4Gi u1.large 2 8Gi u1.xlarge 4 16Gi u1.2xlarge 8 32Gi u1.4xlarge 16 64Gi u1.8xlarge 32 128Gi
Same CPU characteristics as U Series, but memory is overcommitted for higher density.
Name vCPUs Memory o1.nano 1 512Mi o1.micro 1 1Gi o1.small 1 2Gi o1.medium 1 4Gi o1.large 2 8Gi o1.xlarge 4 16Gi o1.2xlarge 8 32Gi o1.4xlarge 16 64Gi o1.8xlarge 32 128Gi
Dedicated CPU — Physical cores exclusively assigned to vCPUs.Hugepages — Improved memory performance.Isolated Emulator Threads — Hypervisor threads isolated from vCPUs.vNUMA — Guest-visible NUMA topology.vCPU-to-Memory Ratio 1:2 .
Name vCPUs Memory cx1.medium 1 2Gi cx1.large 2 4Gi cx1.xlarge 4 8Gi cx1.2xlarge 8 16Gi cx1.4xlarge 16 32Gi cx1.8xlarge 32 64Gi
Hugepages — Improved memory performance.Burstable CPU .vCPU-to-Memory Ratio 1:8 .
Name vCPUs Memory m1.large 2 16Gi m1.xlarge 4 32Gi m1.2xlarge 8 64Gi m1.4xlarge 16 128Gi m1.8xlarge 32 256Gi
Hugepages and Dedicated CPU .Isolated Emulator Threads .Requires nodes capable of running realtime applications.
Name vCPUs Memory rt1.micro 1 1Gi rt1.small 1 2Gi rt1.medium 1 4Gi rt1.large 2 8Gi rt1.xlarge 4 16Gi rt1.2xlarge 8 32Gi rt1.4xlarge 16 64Gi rt1.8xlarge 32 128Gi
Name vCPUs Memory gn1.xlarge 4 16Gi gn1.2xlarge 8 32Gi gn1.4xlarge 16 64Gi gn1.8xlarge 32 128Gi
Instance profiles define guest OS-specific defaults and preferences (e.g., default disk bus, network model, firmware settings). They are provided by Cozystack as KubeVirt preference resources.
Profile Guest OS alpine Alpine cirros Cirros debian Debian fedora Fedora (amd64) fedora.arm64 Fedora (arm64) opensuse.leap OpenSUSE Leap opensuse.tumbleweed OpenSUSE Tumbleweed sles SUSE Linux Enterprise Server ubuntu Ubuntu
Profile Guest OS centos.7 CentOS 7 centos.stream8 CentOS Stream 8 centos.stream9 CentOS Stream 9 centos.stream10 CentOS Stream 10 rhel.7 Red Hat Enterprise Linux 7 rhel.8 Red Hat Enterprise Linux 8 rhel.9 Red Hat Enterprise Linux 9 (amd64) rhel.9.arm64 Red Hat Enterprise Linux 9 (arm64) rhel.10 Red Hat Enterprise Linux 10 Beta (amd64) rhel.10.arm64 Red Hat Enterprise Linux 10 Beta (arm64)
Profile Guest OS 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)
Tip
For GPU passthrough VMs, use a gn1.* instance type and ensure the guest OS has the appropriate NVIDIA drivers installed.
