KVM : Create a Virtual Machine#12014/07/11

	Install GuestOS and create a Virtual Machine. This example shows to install CentOS 7.
[1]	Install GuestOS on text mode via network, it's OK on Console or remote connection with Putty and so on. Furthermore, Virtual Machine's images are placed at /var/lib/libvirt/images by default as a Storage Pool, but this example shows to create and use a new Storage Pool.

[root@dlp ~]#

mkdir -p /var/kvm/images

# create a new Storage Pool

[root@dlp ~]#

virt-install \

--name centos7 \
--ram 4096 \
--disk path=/var/kvm/images/centos7.img,size=30 \
--vcpus 2 \
--os-type linux \
--os-variant rhel7 \
--network bridge=br0 \
--graphics none \
--console pty,target_type=serial \
--location 'http://ftp.iij.ad.jp/pub/linux/centos/7/os/x86_64/' \
--extra-args 'console=ttyS0,115200n8 serial'

Starting install...

# start installation

The example of options above means like follows. There are many options for others, make sure with "man virt-install".

--name

specify the name of Virtual Machine

--ram

specify the amount of memories of Virtual Machine

--disk path=xxx ,size=xxx

'path=' ⇒ specify the location of disks of Virtual Machine
'size=' ⇒ specify the amount of disks of Virtual Machine

--vcpus

specify the virtual CPUs

--os-type

specify the type of GuestOS

--os-variant

specify the kind of GuestOS - possible to confirm the list with the command below
# osinfo-query os

--network

specify network types of Virtual Machine

--graphics

specify the kind of graphics. if set 'none', it means nographics.

--console

specify the console type

--location

specify the location of installation where from

--extra-args

specify parameters that is set in kernel

[2]	Install on text mode, it's the same with common procedure of installation. After finishing installation, reboot first and then login prompt is shown like follows.

CentOS Linux 7 (Core)
Kernel 3.10.0-123.el7.x86_64 on an x86_64

localhost login:

[3]	Move to GuestOS to HostOS with Ctrl + ] key. Move to HostOS to GuestOS with a command 'virsh console (name of virtual machine)'.

[root@localhost ~]#

# push Ctrl + ]

[root@dlp ~]#

# Host's console

[root@dlp ~]#

virsh console centos7

# move to Guest

Connected to domain www

Escape character is ^]

# Enter key

[root@localhost ~]#

# Guest's console

[4]	Because after installing GuestOS from network, it is minimum settings, so it's useful to save it as a template in order to create new virtual machines later.

[root@dlp ~]#

virt-clone --original centos7 --name template --file /var/kvm/images/template.img

Allocating 'template.img' | 20 GB 01:44

Clone 'template' created successfully.

[root@dlp ~]#

ll /var/kvm/images/template.img

# disk image

-rwxr-xr-x 1 root root 32212254720 Jul 11 23:34 /var/kvm/images/template.img
[root@dlp ~]#

ll /etc/libvirt/qemu/template.xml

# xml file

-rw------- 1 root root 1843 Jul 11 23:32 /etc/libvirt/qemu/template.xml

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