Create: KVM Instance

The following information describes how to create a virtual machine using the virt-install utility.

What Do You Need?

The following system requirements must be met:
- Virtualization packages are installed on the host system. See Install Virtualization Packages for more details.
- A minimum of one virtual storage pool must exist to create a virtual machine. Note that a virtualization storage pool is automatically provided in the /var/lib/libvirt/images directory. See Storage Pools: Create and Manage for more details.
- A compatible guest OS is required to create a virtual machine. See KVM Guest: Operating Systems for more details.
- All minimum host system hardware requirements must be met to create, run, and manage KVM instances. See KVM Host: System Requirements for more details.
- The libvirt services must be started and enabled. See Libvirtd Service: Management Tasks for more details.
Administrator privileges.

Steps

Using the CLI, follow these steps to create a virtual machine.

To create a virtual machine, use the virt-install command and its options to define the resources required. For example:

Virtual Machine Creation: Options

 virt-install \
 --name [unique-virtual-machine-name]
 --memory [allocated-MiB-memory-size] 
 --vcpus [integer-vcpus-value-for-guest]
 --location [installation-source-path] 
 --disk [type-and-size]
 --os-variant=[os-verison]
 --network [default]
 --graphics [none]

Note:

For a complete list of virt-install options, see the virt-install(1) man page. Or, for a quick list of virt-install options, type: virt-install --help.

Where:

--name [unique-virtual-machine-name]

Mandatory Option:

Provide a unique name to the virtual machine.. The assigned name is registered as a domain within libvirt.

--memory [allocated-MiB-memory-size]

Mandatory Option:

Identify the amount of memory to be allocated to the guest, in MiB.

--vcpus [integer-vcpus-value-for-guest]

Mandatory Option:

Identify the number of virtual CPUs available for use by guest OS.

--disk [type-and-size]

Mandatory Option:

Identify the appropriate values for disk type and size, for example:

Disk hardware size:

--disk size=[capacity size in gigabytes]

Disk storage pool path

--disk /storage-pool-path/volume-path,size=#

Disk image media file path

--disk=/iso-images/ol8-dvd.iso,device=cdrom

Special considerations:

If a path isn't specified the disk image is automatically created as a qcow file format.
If virt-install is run as root, the disk image is created in /var/lib/libvirt/images/ and is named using the name specified for the VM at install.
If virt-install is run as an ordinary user, the disk image is created in $HOME/.local/share/libvirt/images/

--location [installation-source-path]

Mandatory Option

Identify the OS installation source location, for example:

ISO file
an expanded installation resource hosted at a local path
an expanded installation resource hosted remotely on an HTTP or NFS server.

Note:

For a list other source installation options, see the virt-install (1)– Linux man page.

--os-variant [os-version]

The os-variant option is optional. You can use this option to optimize the performance of the guest configuration.

To obtain valid "--os-variant" values, type: osinfo-query os

--network [default]

The network option is optional. When the "--network" option isn't specified, or when the "--network default" options is specified, the guest will connect to the default network.

For other network configuration options, see the virt-install (1) – Linux man page.

--graphics [none]

The graphics option is optional.

This option lets you specify the display type used for interactive guest installation.

Note that when "–-graphics none" is specified, a text-only installation display is available.

To display a graphical console for a guest installation, you can use the virt-viewer tool. For more information about configuring the virt-viewer, see the virt-viewer(1) --Linux man page.

Based on the virt-install options specified, the virtual machine is created and the guest OS is automatically installed.

Virtual Machine Creation Examples: See Virt-Install: Command Line Examples

After creating the virtual machine, you can:
1. Start the virtual machine.
  
  For details, see KVM: Start Instance.
2. Connect to the virtual machine.

Virt-Install: Command Line Examples

The following information provides command-line examples for using virt-install to create virtual machine instances with a guest OS.

Guest OS: Oracle Linux 9

Scenario: ISO image - text-mode only install.
```
virt-install \
    --name ol9-guest-demo --memory 16384 --vcpus 16 --disk size=280 \
    --os-variant ol9.0 --location ol9.iso \
    --graphics none --extra-args='console=ttyS0'
```
Description: Creates a KVM instance named ol9-guest-demo using an ol9.iso image file in text-only mode, without graphics. It connects the guest console to the serial console. The VM has 16384 MiB of memory, 16 vCPUs, and 280 GiB disk. Note that this guest installation example might be useful when connecting to a host over a slow network link.
Scenario: URL installation tree path - automated Kickstart install.
```
virt-install \
    --graphics vnc \
    --name ol9-guest-demo1 --memory 2048 --vcpus 2 --disk size=160 \
    --os-variant ol9.0 --location http://example.com/OS-install \
    --initrd-inject /home/uniquename/ks.cfg --extra-args="inst.ks=file:/ks.cfg console=tty0 console=ttyS0,115200n8"
```
Description: Creates a VM named ol9-guest-demo1 that installs from the http://example.com/OS-install URL. Note for the installation to start successfully, the URL must contain a working OS installation tree. The OS is automatically configured by the referenced kickstart file (/home/uniquename/ks.cfg). Finally, the VM is allocated with 2048 MiB of RAM, 2 vCPUs, and a 160 GiB qcow2 virtual disk.

Additions for ARM 64 host-based scenarios:
```
%packages
-kernel
kernel-64k
%end
```
These lines ensure that the kickstart file, depicted in the ol9-guest-demo1 scenario, installs the kernel-64k package.

Guest OS: Oracle Linux 8

Scenario: ISO image - live CD
```
virt-install \
    --name ol8-guest-demo --memory 4096 --vcpus 4 \
    --disk none --livecd --os-variant ol8.0 \
    --cdrom /home/uniquename/Downloads/ol8.iso
```
Description: Creates a VM named ol8-guest-demo by using /home/uniquename/Downloads/ol8.iso image to run a Oracle Linux 8 OS from a live CD. No disk space is assigned to this VM, so any changes made during the session aren't preserved. The VM is allocated with 4096 MiB of RAM and 4 vCPUs.

Guest OS: Oracle Linux 7

Scenario: Import disk image - qcow file format
```
virt-install \
    --name ol7-guest-demo --memory 2048 --vcpus 2 \
    --os-variant ol7.0 --import \
    --disk /home/uniquename/backup/disk.qcow2
```
Description: Creates a VM named ol7-guest-demo that connects to an existing disk image (/home/uniquename/backup/disk.qcow2). The VM is allocated with 2048 MiB of RAM and 2 vCPUs. Note that the os-variant option is highly recommended when importing a disk image. In cases when the os-variant option isn't specified, the performance of the created VM might be negatively affected.