[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Re: [PATCH]Change default network schema in network-bridge
On Wed, Jun 24, 2009 at 03:38:25PM +0100, Ian Jackson wrote: > Daniel P. Berrange writes ("[Xen-devel] Re: [PATCH]Change default network > schema in network-bridge"): > > These days my recommendation > > is for people to set '(network-script /bin/true)' and then just use their > > OS distributions network scripts to add a bridge device. > > This is definitely the best way of doing things. I've always thought > that the network-script thing was a terrible hack (and it's flaky > too). > > Perhaps we should keep the script, but change the defaults and the > documentation ? > > > http://wiki.libvirt.org/page/Networking#Bridged_networking_.28aka_.22shared_physical_device.22.29 > > Would you be able to resubmit (some of) that as a .txt file for > inclusion in the xen-unstable tree, or copy it to the Xen wiki ? > I'm not exactly sure of the authorship and copyright status so I'm > reluctant to just do that myself. I wrote initial content, the remainder is just bug fixes/tweaks too minor to be copyrightable. Here is a simplified text version that just covers the bridging setup, without the other libvirt specific bits Signed off by: Daniel P. Berrange <berrange@xxxxxxxxxx> Regards, Daniel Native OS bridge configuration ============================== The traditional "network-bridge" script attempts to modify existing active network interfaces to enable bridging. For non-trivial network configurations though this can be error prone, and the temporary disruption to network connectivity can upset some applications. This document outlines how to configure bridging using an OS' native network configuration files. Disabling Xen's network scripts ------------------------------- The first step is to check XenD's network bridge is disabled by editing /etc/xen/xend-config.sxp and changing the line (network-script network-bridge) To be (network-script /bin/true) Fedora/RHEL Bridging ==================== This outlines how to setup bridging using standard network initscripts present in Fedora or RHEL distros and their derivatives Disabling NetworkManager ------------------------ As of time of writing (Fedora 11) NetworkManager does not support bridging, so it is neccessary to disable it, and revert to "classic" network initscripts # chkconfig NetworkManager off # chkconfig network on # service NetworkManager stop # service network start NB, as an alternative to turning off NetworkManager, you can also add a line "NM_CONTROLLED=no" to the ifcfg-XXX scripts below Creating network initscripts ---------------------------- In the /etc/sysconfig/network-scripts directory it is necccessary to create 2 config files. The first (ifcfg-eth0) defines your physical network interface, and says that it will be part of a bridge: # cat > ifcfg-eth0 <<EOF DEVICE=eth0 HWADDR=00:16:76:D6:C9:45 ONBOOT=yes BRIDGE=br0 EOF Obviously change the HWADDR to match your actual NIC's address. You may also wish to configure the device's MTU here using e.g. MTU=9000. The second config file (ifcfg-br0) defines the bridge device: # cat > ifcfg-br0 <<EOF DEVICE=br0 TYPE=Bridge BOOTPROTO=dhcp ONBOOT=yes DELAY=0 EOF WARNING: The line TYPE=Bridge is case-sensitive - it must have uppercase 'B' and lower case 'ridge' After changing this restart networking (or better still reboot) # service network restart The final step is to configure iptables to allow all traffic to be forwarded across the bridge # echo "-I FORWARD -m physdev --physdev-is-bridged -j ACCEPT" > /etc/sysconfig/iptables-forward-bridged # lokkit --custom-rules=ipv4:filter:/etc/sysconfig/iptables-forward-bridged # service libvirtd reload Alternatively, you can prevent bridged traffic getting pushed through the host's iptables rules completely. In /etc/sysctl.conf add # cat >> /etc/sysctl.conf <<EOF net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-arptables = 0 EOF # sysctl -p /etc/sysctl.conf You should now have a "shared physical device", to which guests can be attached and have full LAN access # brctl show bridge name bridge id STP enabled interfaces br0 8000.000e0cb30550 no eth0 Debian/Ubuntu Bridging ======================= This outlines how to setup bridging using standard network interface config files on Debian / Ubuntu distributions and their derivatives Disabling NetworkManager ------------------------ Stop network manager sudo /etc/dbus-1/event.d/26NetworkManagerDispatcher stop sudo /etc/dbus-1/event.d/25NetworkManager stop Create two files with only the word 'exit' in them. These files are: /etc/default/NetworkManager /etc/default/NetworkManagerDispatcher Altering the interface config ----------------------------- First take down the interface you wish to bridge ifdown eth0 Edit /etc/network/interfaces and find the config for the physical interface, which looks something like allow-hotplug eth0 iface eth0 inet static address 192.168.2.4 netmask 255.255.255.0 network 192.168.2.0 broadcast 192.168.2.255 gateway 192.168.2.2 Remove the 'allow-hotplug eth0' line, replacing it with 'auto br0', and change the next line with iface name to 'br0', so it now starts with auto br0 iface br0 inet static And then define the interface as being a bridge and specify its ports bridge_ports eth0 bridge_stp off bridge_maxwait 5 The complete config should now look like auto br0 iface br0 inet static address 192.168.2.4 netmask 255.255.255.0 network 192.168.2.0 broadcast 192.168.2.255 gateway 192.168.2.2 bridge_ports eth0 bridge_stp off bridge_maxwait 5 The interface can now be started with ifup br0 Finally add the '/etc/sysctl.conf' settings net.bridge.bridge-nf-call-ip6tables = 0 net.bridge.bridge-nf-call-iptables = 0 net.bridge.bridge-nf-call-arptables = 0 And then load the settings with sysctl -p /etc/sysctl.conf You should now have a "shared physical device", to which guests can be attached and have full LAN access # brctl show bridge name bridge id STP enabled interfaces br0 8000.000e0cb30550 no eth0 Other operating systems / distributions ======================================= [...send patches to this file with instructions....] -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :| _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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