7.3. Installing guests with PXE
This section covers the steps required to install guests with PXE. PXE guest installation requires a shared network device, also known as a network bridge. The procedures below covers creating a bridge and the steps required to utilize the bridge for PXE installation.
Create a new bridge
- Create a new network script file in the
/etc/sysconfig/network-scripts/directory. This example creates a file namedifcfg-installationwhich makes a bridge namedinstallation.# cd /etc/sysconfig/network-scripts/ # vim ifcfg-installation DEVICE=installation TYPE=Bridge BOOTPROTO=dhcp ONBOOT=yes
Warning
The line,TYPE=Bridge, is case-sensitive. It must have uppercase 'B' and lower case 'ridge'.Important
Prior to the release of Red Hat Enterprise Linux 5.9, a segmentation fault can occur when the bridge name contains only uppercase characters. Please upgrade to 5.9 or newer if uppercase names are required. - Start the new bridge by restarting the network service. The
ifup installationcommand can start the individual bridge but it is safer to test the entire network restarts properly.# service network restart
- There are no interfaces added to the new bridge yet. Use the
brctl showcommand to view details about network bridges on the system.# brctl show bridge name bridge id STP enabled interfaces installation 8000.000000000000 no virbr0 8000.000000000000 yes
Thevirbr0bridge is the default bridge used bylibvirtfor Network Address Translation (NAT) on the default Ethernet device.
Add an interface to the new bridge
Edit the configuration file for the interface. Add theBRIDGEparameter to the configuration file with the name of the bridge created in the previous steps.# Intel Corporation Gigabit Network Connection DEVICE=eth1 BRIDGE=installation BOOTPROTO=dhcp HWADDR=00:13:20:F7:6E:8E ONBOOT=yes
After editing the configuration file, restart networking or reboot.# service network restart
Verify the interface is attached with thebrctl showcommand:# brctl show bridge name bridge id STP enabled interfaces installation 8000.001320f76e8e no eth1 virbr0 8000.000000000000 yes
Security configuration
Configureiptablesto allow all traffic to be forwarded across the bridge.# iptables -I FORWARD -m physdev --physdev-is-bridged -j ACCEPT # service iptables save # service iptables restart
Note
Alternatively, prevent bridged traffic from being processed byiptablesrules. In/etc/sysctl.confappend the following lines:net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-arptables = 0
Reload the kernel parameters configured withsysctl.# sysctl -p /etc/sysctl.conf
Restart libvirt before the installation
Restart thelibvirtdaemon.# service libvirtd restart
The bridge is configured, you can now begin an installation.
PXE installation with virt-install
For virt-install append the --network=bridge:installation installation parameter where installation is the name of your bridge. For PXE installations use the --pxe parameter.
Example 7.3. PXE installation with virt-install
# virt-install --accelerate --hvm --connect qemu:///system \
--network=bridge:installation --pxe\
--name EL10 --ram=756 \
--vcpus=4
--os-type=linux --os-variant=rhel5
--file=/var/lib/libvirt/images/EL10.img \
PXE installation with virt-manager
The steps below are the steps that vary from the standard virt-manager installation procedures. For the standard installations rsee Chapter 8, Guest operating system installation procedures.
Select PXE
Select PXE as the installation method.
Select the bridge
Select Shared physical device and select the bridge created in the previous procedure.
Start the installation
The installation is ready to start.
A DHCP request is sent and if a valid PXE server is found the guest installation processes will start.
