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Chapter 2. System Requirements

2.1. Hardware requirements
2.1.1. Management Server Requirements
2.1.2. Virtualization Host Requirements
2.2. Software requirements
2.2.1. Operating Systems
2.2.2. Client Requirements
2.2.3. Red Hat Network (RHN)
2.2.4. Directory Services
2.2.5. Firewall Configuration
This chapter outlines the hardware and software requirements for installing the Red Hat Enterprise Virtualization platform. The requirements outlined herein are based on the minimum requirements for successful installation, configuration, and operation of a Red Hat Enterprise Virtualization environment.
Production Red Hat Enterprise Virtualization installations will have additional requirements in line with the relative workloads expected of them. The additional requirements for your specific implementation of the Red Hat Enterprise Virtualization product need to be determined by your solution architect. Guidance on planning your Red Hat Enterprise Virtualization environment is provided in Chapter 9, Planning your Data Center.

Important — Listed Requirements are Mandatory

All listed requirements must be met before installation commences. Without the listed requirements installation of a fully functional Red Hat Enterprise Virtualization environment as described in this guide will not be possible.
Before commencing the installation you must consult the latest version of the Red Hat Enterprise Virtualization — Manager Release Notes.

2.1. Hardware requirements

This section outlines the minimum hardware required to install, configure, and operate a Red Hat Enterprise Virtualization environment. To setup a Red Hat Enterprise Virtualization environment it is necessary to have, at least:
  • one machine to act as the management server,
  • one or more machines to act as virtualization hosts - at least two are required to support migration and power management,
  • one or more machines to use as clients for accessing the Administration Portal.
  • storage infrastructure provided by NFS, iSCSI, SAN, or local storage.
The hardware required for each of these systems is further outlined in the following sections. The Red Hat Enterprise Virtualization environment also requires storage infrastructure that is accessible to the virtualization hosts. Storage infrastructure must be accessible using NFS, iSCSI, FC, or locally attached to virtualization hosts.

2.1.1. Management Server Requirements

The minimum and recommended hardware requirements outlined here are based on a typical small to medium sized installation. The exact requirements vary between deployments based on sizing and load. Please use these recommendations as a guide only.
Minimum
  • A dual core CPU.
  • 4 GB of available system RAM that is not being consumed by existing processes.
  • 25 GB of locally accessible, writeable, disk space.
  • 1 Network Interface Card (NIC) with bandwidth of at least 1 Gbps.
Recommended
  • A quad core CPU or multiple dual core CPUs.
  • 16 GB of system RAM.
  • 50 GB of locally accessible, writeable, disk space.
  • 1 Network Interface Card (NIC) with bandwidth of at least 1 Gbps.
The Red Hat Enterprise Virtualization Manager runs on Red Hat Enterprise Linux. To confirm whether or not specific hardware items are certified for use with Red Hat Enterprise Linux refer to http://www.redhat.com/rhel/compatibility/hardware/.

2.1.2. Virtualization Host Requirements

Red Hat Enterprise Virtualization Hypervisors and Red Hat Enterprise Linux Hosts have a number of hardware requirements and supported limits.

2.1.2.1. CPU Requirements

Virtualization hosts must have at least one CPU. All CPUs must support
  • the Intel® 64 or AMD64 CPU extensions, and
  • the AMD-V™ or Intel VT® hardware virtualization extensions.
Additionally a maximum of 128 physical CPUs per virtualization host is currently supported. To check that your processor supports the required virtualization extensions, and that they are enabled:
  • At the Red Hat Enterprise Linux or Red Hat Enterprise Virtualization Hypervisor 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 rescue parameter.
  • 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 kvm modules are loaded in the kernel:
    # lsmod | grep kvm
    If the output includes kvm_intel or kvm_amd then the kvm hardware virtualization modules are loaded and your system meets requirements.

2.1.2.2. RAM Requirements

Virtualization hosts must have at least 10 GB of RAM. A minimum of an additional 1 GB for each virtual machine is also recommended. The amount of RAM required for each guest varies depending on:
  • the guest operating system's requirements,
  • the guests' application requirements, and
  • memory activity and usage of guests.
The fact that KVM is able to over-commit physical RAM for virtualized guests must also be taken into account. This allows provisioning of guests with RAM requirements greater than physically present on the basis where not all guests will be at peak load concurrently. KVM does this by only allocating RAM for guests as required and shifting underutilized guests into swap.
Additionally a maximum of 1 TB of RAM per virtualization host is currently supported.

2.1.2.3. Storage Requirements

Virtualization hosts require local storage to store configuration, logs, kernel dumps, and for use as swap space. The minimum storage requirements of the Red Hat Enterprise Virtualization Hypervisor are documented in this section. 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 the Red Hat Enterprise Virtualization Hypervisor.
It is recommended that each virtualization host has at least 10 GB of internal storage. The minimum supported internal storage for each Hypervisor is the total of that required to provision the following partitions:
  • The root partitions require at least 512 MB of storage.
  • The configuration partition requires at least 8 MB of storage.
  • The recommended minimum size of the logging partition is 2048 MB.
  • The data partition requires at least 256 MB of storage. Use of a smaller data partition may prevent future upgrades of the Hypervisor from the Red Hat Enterprise Virtualization Manager. By default all disk space remaining after allocation of swap space will be allocated to the data partition.
  • The swap partition requires at least 8 MB of storage. The recommended size of the swap partition varies depending on both the system the Hypervisor is being installed upon and the anticipated level of overcommit for the environment. Overcommit allows the Red Hat Enterprise Virtualization environment to present more RAM to guests than is actually physically present. The default overcommit ratio is 0.5.
    The recommended size of the swap partition can be determined by:
    • Multiplying the amount of system RAM by the expected overcommit ratio, and adding
    • 2 GB of swap space for systems with 4 GB of RAM or less, or
    • 4 GB of swap space for systems with between 4 GB and 16 GB of RAM, or
    • 8 GB of swap space for systems with between 16 GB and 64 GB of RAM, or
    • 16 GB of swap space for systems with between 64 GB and 256 GB of RAM.
    Example 2.1. Calculating Swap Partition Size
    For a system with 8 GB of RAM this means the formula for determining the amount of swap space to allocate is:
    (8 GB x 0.5) + 4 GB = 8 GB

Important — Fakeraid Devices are not Supported

The Red Hat Enterprise Virtualization Hypervisor does not support installation on fakeraid devices. Where a fakeraid device is present it must be reconfigured such that it no longer runs in RAID mode.
  1. Access the RAID controller's BIOS and remove all logical drives from it.
  2. Change controller mode to be non-RAID. This may be referred to as compatibility or JBOD mode.
Access the manufacturer provided documentation for further information related to the specific device in use.

2.1.2.4. PCI Device Requirements

Virtualization hosts must have at least one network interface with a minimum bandwidth of 1 Gbps. It is recommended that each virtualization host have two network interfaces with a minimum bandwidth of 1 Gbps to support network intensive activity, including virtual machine migration.