CentOS 5
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Create a Virtual Machine#12015/01/16

Install GuestOS to create a Virtual Machine. This example shows to install CentOS 5.
[1] Install 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.
# create a new Storage Pool

[root@dlp ~]#
mkdir -p /var/kvm/images

[root@dlp ~]#
virt-install \
--name www \
--ram 3072 \
--disk path=/var/kvm/images/www.img,size=30 \
--vcpus 2 \
--os-type linux \
--os-variant rhel5.4 \
--network bridge=br0 \
--nographics \
--location 'http://ftp.jaist.ac.jp/pub/Linux/CentOS/5.11/os/x86_64/' \
--extra-args 'console=ttyS0,115200n8 serial'
Starting install...
# start installation
# note: virt-install will be fail on CentOS 5 if RAM is set over 4G

# note: if you set over 4G RAM, change to it after creating a VM or set it on GUI with virt-manager

The example of options above means like below. There are many options for others, make sure eith "man virt-install".
specify the name of Virtual Machine
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
specify the virtual CPUs
specify the type of GuestOS
specify the kind of GuestOS
specify network types of Virtual Machine
not use graphics
specify the location of installation where from
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 follwos.
CentOS release 5.11 (Final)
Kernel 2.6.18-398.el5 on an x86_64
localhost.localdomain login:
[root@localhost ~]#
[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 ~]#
# Ctrl + ] key

[root@dlp ~]#
# Host's console
[root@dlp ~]#
virsh console www
# move to Guest

Connected to domain www
Escape character is ^]
# Enter
[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@localhost ~]#
# Ctrl + ] key

[root@dlp ~]#
# Host's console
[root@dlp ~]#
virt-clone --original www --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 Jan 16 22:52 /var/kvm/images/template.img
[root@dlp ~]#
ll /etc/libvirt/qemu/template.xml
# xml file

-rw------- 1 root root 1130 Jan 16 22:50 /etc/libvirt/qemu/template.xml
[6] Define a new Storage Pool.
[root@dlp ~]#
mkdir /etc/libvirt/storage

[root@dlp ~]#
vi /etc/libvirt/storage/disk01.xml
# create new

<pool type='dir'>
# any name

# specify pool directory

# define the pool

[root@dlp ~]#
virsh pool-define /etc/libvirt/storage/disk01.xml

Pool disk01 defined from /etc/libvirt/storage/disk01.xml
# start the pool

[root@dlp ~]#
virsh pool-start disk01

Pool disk01 started
# set auto-start

[root@dlp ~]#
virsh pool-autostart disk01

Pool disk01 marked as autostarted
# show the pool list

[root@dlp ~]#
virsh pool-list


# show details

[root@dlp ~]#
virsh pool-info disk01

Name:           disk01
UUID:           0e68d1b2-6830-d10c-29c6-83ae2aa7d792
State:          running
Persistent:     yes
Autostart:      yes
Capacity:       143.24 GB
Allocation:     4.27 GB
Available:      138.98 GB
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