kvm support disk less booting of operating systems over network, kvm default network can be configured to act a pxe server.
packages required to setup pxe boot, tfp is a udp based file sharing service used to push the required files for pxe boor, /var/lib/tftpboot will be directory for tftp server.
we need to copy syslinux files to this location by creating a directory called pxelinux.
As the vm boot up with option from network boot , it will be able to fetch intial files required to boot from pxelinux.0 , installation files of iso can be fetched from http , nfs , or ftp over network.
i am running http server to provide files for installation
for creating a grub menu, create a directory pxelinux.cfg with file default
cat default default vesamenu.c32 prompt 1 timeout 600 display boot.msg label linux menu label ^Install or upgrade an existing system menu default kernel vmlinuz append initrd=initrd.img inst.repo=http://192.168.122.1/centos7/ label vesa menu label Install system with ^basic video driver kernel vmlinuz append initrd=initrd.img xdriver=vesa nomodeset label rescue menu label ^Rescue installed system kernel vmlinuz append initrd=initrd.img rescue label local menu label Boot from ^local drive localboot 0xffff label memtest86 menu label ^Memory test kernel memtest append -
# sudo cp /usr/share/syslinux /var/lib/tftpboot/pxelinux/ here is the contents of /var/lib/tftpboot/pxelinux/ # tree -d /var/lib/tftpboot/pxelinux/ /var/lib/tftpboot/pxelinux/ ├── com32 │ └── include │ ├── bitsize │ ├── bitsize32 │ ├── bitsize64 │ ├── gplinclude │ │ ├── acpi │ │ ├── disk │ │ ├── dmi │ │ ├── vpd │ │ └── zzjson │ ├── hw │ ├── klibc │ │ ├── i386 │ │ └── x86_64 │ ├── linux │ ├── netinet │ ├── sys │ │ ├── i386 │ │ └── x86_64 │ └── syslinux ├── diag ├── dosutil └── pxelinux.cfg
# dnf install syslinux-tftpboot syslinux-devel syslinux-common tftpd
After the packages are installed , enable and run tfp service.
#systemctl start tftp #systemctl enable tftp
here is my default network xml file configured for pxe install.
# virsh net-dumpxml default
<network>
<name>default</name>
<uuid>cdaebe20-c72d-4434-932e-58e00de5e837</uuid>
<forward mode='nat'>
<nat>
<port start='1024' end='65535'/>
</nat>
</forward>
<bridge name='virbr0' stp='on' delay='0'/>
<mac address='52:54:00:d9:5b:b9'/>
<ip address='192.168.122.1' netmask='255.255.255.0'>
<dhcp>
<range start='192.168.122.2' end='192.168.122.254'/>
<host mac='52:54:00:d8:a0:f4' name='centosext' ip='192.168.122.11'/>
<host mac='52:54:00:2d:07:d3' name='centosext1' ip='192.168.122.22'/>
<host mac='52:54:00:17:1a:99' name='centosext2' ip='192.168.122.33'/>
<host mac='52:54:00:7b:f9:f3' name='centosext3' ip='192.168.122.44'/>
<host mac='52:54:00:df:5f:2f' name='centosext4' ip='192.168.122.55'/>
<host mac='52:54:00:d8:a0:f4' name='centosext5' ip='192.168.122.66'/>
<host mac='52:54:00:82:18:49' name='chefnode1' ip='192.168.122.77'/>
<host mac='52:54:00:8d:10:87' name='chefnode2' ip='192.168.122.88'/>
<host mac='52:54:00:c6:41:eb' name='chefnode3' ip='192.168.122.99'/>
<host mac='52:54:00:7a:73:a0' name='chefnode4' ip='192.168.122.111'/>
<bootp file='/pxelinux/pxelinux.0' server='192.168.122.1'/>
</dhcp>
</ip>
</network>
Setting up a lvm partition for the new vm,
#sudo virsh vol-create-as store pxe1 10G Vol pxe1 created
Lets install os from pxe, after executing the below virt-install command , connect from any vnc client on host ip address port 5900
#virt-install --name pxe1 --ram 512 --disk path=/dev/store/pxe1 --vcpus 2 --pxe --os-type linux --os-variant rhel7 --network network=default --graphics vnc,listen=0.0.0.0 --accelerate Starting install...
