Virt-install

External

• RHEL7 Virtualization Administration - Creating Guests with virt-install

Internal

• Linux Virtualization Operations

Overview

virt-install is a command-line utility for provisioning new virtual machines. It comes as part of the "virt-install" RPM package.

virt-install needs root privileges to work.

Documentation

virt-install --help

Procedure

Prerequisites

If not already declared, create an "iso-images" directory-based storage pool and place the DVD ISO image there. The procedure is described here:

Directory-Based Storage Pool Configuration

The command assumes that /main-storage-pool was created and it is active.

Virtual Machine Creation

virt-install 
 --name <virtual-machine-name>
 --memory 1024 
 --vcpus 2 
 --os-variant=<os-variant>
 --location /iso-images/rhel-server-7.3-x86_64-dvd.iso 
 --extra-args="console=tty0 console=ttyS0,115200n8" 
 --disk=/iso-images/rhel-server-7.3-x86_64-dvd.iso,device=cdrom
 --disk=/main-storage-pool/testvm-01.img,size=4
--network=default \
--graphics none

Verity that a storage volume is automatically added to iso-images after running this:

vol-list --pool iso-images

Mandatory Options

Guest Virtual Machine Name

The name of the guest virtual machine must be specified with --name or -n:

--name test-01

It is recommended to follow the virtual machine name convention when naming virtual machine.

Memory Amount

virt-install needs the amount of memory allocated to the guest, in MiB, which must be specified with --memory:

--memory 1024

Equivalent: --ram and -r.

The amount can be changed after the virtual machine is creating by editing the definition with virsh edit.

Guest Storage Specification

One of the following must be specified:

--disk

Specifies guest storage, relative to the storage provided by the virtualization host. The most common option is to refer storage from a storage pool, but other options are also available.

It is recommended to follow the virtual machine image name convention when naming the media to use for storing the virtual machine image.

--disk size=10

Specified a new 10 GiB image on the default storage pool.

--disk /storage-pool-path/volume-path,size=8,sparse=false,cache=none

--disk device=cdrom,bus=scsi

--disk=?

Installation Method Option

--os-variant

This is an important option, used to optimize guest configuration. Valid "--os-variant" values can be obtained with osinfo-query os command

Example:

--os-variant=rhel7.3

--os-type

The quest operating system type.

Example:

--os-type=linux

Note that man girt-install does not refer --os-type, it can probably be inferred from --os-variant.

Distribution Tree Installation Source

The distribution tree installation source is specified with --location. virt-install can fetch a bootable kernel/initrd pair from the source declared with --location to launch the install.

Options:

ISO File

--location /path/to/iso-file.iso

--location is followed by a path to an ISO file containing an installable distribution image. Note that the file should be readable by the "qemu" user. Also note that the file will not be accessible by the guest after initial boot, so the OS installer will need another way to access the rest of the install media. For an example of how to do that, see Text-Based Anaconda Guest Installation Example. An equivalent format, though less flexible as it does not accept --extra-args, uses --cdrom option:

--cdrom /path/to/iso-file.iso | URL-with-the-same-format-as-the-ones-used-for--location-argument

For an end-to-end example of how to create a guest VM from a CDROM image, see:

Text-Based Anaconda Guest Installation

Directory

--location /directory

--location is followed by a path to a local directory containing an installable distribution image. Note that the directory will not be accessible by the guest after initial boot, so the OS installer will need another way to access the rest of the install media. For an example of how to do that, see Text-Based Anaconda Guest Installation Example.

HTTP Server

--location http://host/path 

FTP Server

--location ftp://host/path

NFS Server

--location nfs:host:/path
--location nfs://host/path

Optional Installation Method Option

--boot

--boot BOOT_OPTS is used to configure guest boot settings:

--boot hd,cdrom,menu=on

--boot init=/sbin/init

--pxe

Boot from the network using the PXE protocol.

--import

Build guest around an existing disk image.

--extra-args=

--extra-args EXTRA_ARGS Additional arguments to pass to the install kernel booted from --location.

Optional Configuration

Graphics

Specifies the type of graphical tool to use for interactive installation or can be set to "none" for a fully automated installation.

--graphics none|spice|...

Network Specification

The network specification is optional. If "--network" is not used, or if "--network default" is used, the guest will connect to the default network.

Otherwise, it can be specified with '--network NETWORK-SPEC', as follows:

TODO:

--network bridge=mybr0

TODO: If using a bridge, the bridge must be previously created, as described here Bridged Networking Configuration.

TODO:

--network network=my_libvirt_virtual_net

TODO:

--network network=mynet,model=virtio,mac=00:11..

TODO:

--network none

--vcpus

Specifies the number of virtual CPUs for the guest:

--vcpus 2

The amount can be changed after the virtual machine is creating by editing the definition with virsh edit.

Virtualization Platform Options

-v, --hvm

This guest should be a fully virtualized guest.

-p, --paravirt

This guest should be a paravirtualized guest.

--container

This guest should be a container guest.

--virt-type

Represents the hypervisor name to use ("kvm", "qemu", "xen", etc.)

Access to a Host Directory

"--filesystem" can be used to specify a host directory to be available on the guest.

Example:

--filesystem /my/host/source/dir,/dir/in/guest

Examples

virt-install Examples