10.6. Hypervisor Requirements
Red Hat Virtualization Host (RHVH) has a number of hardware requirements and supported limits. The storage requirements for Red Hat Enterprise Linux hosts vary based on the amount of disk space used by their existing configuration but are expected to be greater than those of RHVH.
| Item | Support Limit |
|---|---|
| CPU |
A minimum of 1 physical CPU is required. Red Hat Virtualization supports the use of these CPU models in hosts:
All CPUs must have support for the Intel® 64 or AMD64 CPU extensions, and the AMD-V™ or Intel VT® hardware virtualization extensions enabled. Support for the
No eXecute flag (NX) is also required.
|
| RAM |
The amount of RAM required for each virtual machine varies depending on:
Additionally KVM is able to over-commit physical RAM for virtual machines. It does this by only allocating RAM for virtual machines as required and shifting underutilized virtual machines into swap.
See https://access.redhat.com/articles/rhel-limits for the maximum and minimum supported RAM.
|
| Storage |
The minimum supported internal storage for a host is the total of the following list:
Please note that these are the minimum storage requirements for host installation. It is recommended to use the default allocations which use more storage space.
|
| PCI Devices |
At least one network controller is required with a recommended minimum bandwidth of 1 Gbps.
|
Important
When the Red Hat Virtualization Host boots a message may appear:
Virtualization hardware is unavailable. (No virtualization hardware was detected on this system)
This warning indicates the virtualization extensions are either disabled or not present on your processor. Ensure that the CPU supports the listed extensions and they are enabled in the system BIOS.
To check that processor has virtualization extensions, and that they are enabled:
- At the host boot screen press any key and select the Boot or Boot with serial console entry from the list. Press Tab to edit the kernel parameters for the selected option. After the last kernel parameter listed ensure there is a Space and append the
rescueparameter. - Press Enter to boot into rescue mode.
- At the prompt which appears, determine that your processor has the virtualization extensions and that they are enabled by running this command:
# grep -E 'svm|vmx' /proc/cpuinfo
If any output is shown, the processor is hardware virtualization capable. If no output is shown it is still possible that your processor supports hardware virtualization. In some circumstances manufacturers disable the virtualization extensions in the BIOS. Where you believe this to be the case consult the system's BIOS and the motherboard manual provided by the manufacturer. - As an additional check, verify that the
kvmmodules are loaded in the kernel:# lsmod | grep kvm
If the output includeskvm_intelorkvm_amdthen thekvmhardware virtualization modules are loaded and your system meets requirements.
