Hello all,

Trying to get a Centos 5.5 installing running. Using
kernel-xen.x86_64 2.6.18-194.8.1.el5

Not able to get networking working on Dom0. Not sure if it is
intensional for dom0 not to have connectivity or if something is
broken.

After centos 5.5 is installed it can't even connect to the centos
repos to check for updates.

The only way to fix this is /etc/xen/scripts/network-bridge stop

Would really appreciate any input. Trying to get this running correctly.

I've got guest OS's running OK, but I'd like to have dom0
connectivity. Not sure if it's broken or by design.

Thanks

Hi,

It sounds like a configuration has been broken somewhere, it should still work. It might be worth running an "ifconfig" while it's down to see if it identifies a problem. I don't think mii-tool works when in a hypervisor but ethtool may, might be worth seeing what that returns too. Potentially it's possible the shift of the physical card from ethX to pethX might be responsible, was this a fresh install of CentOS or has it been running other services previous to Xen?

Thanks for your reply. Yes it sure seems like a configuration issue. This question is posted all over the internet, but haven't seen a resolve for it. Quick search for "xen network-bridge setup dom0" .

What I'm trying to do is get connectivity to dom0 and all the domU's . I'm not interested in using the dhcp nat configuration for guests. Only want fixed IP's.

Note: dhcp nat works fine for guests, but not using it
Note: static works fine and guests are able to connect. However they are not able to connect to dom0

I'm interested in all of this for server testing. Specifically for solaris, solaris zones, bsd and linux.

Tried kvm but the performance is terrible

It's odd in that this configuration worked a couple of weeks ago. Reloaded to change dom0 disk layout and test kvm options. Has not worked since. Hench it appears to be a configuration issue

It is pretty much a standard install of centos 5.5 using xen. The only options I didn't install with we're IP6 disable, selinux disable and iptables disable.

Interesting when the box is fired up iptables is still running with rules.

I'll attach ifconfig, and netstat settings

Settings show gotten by using
/etc/xen/scripts/network-bridge stop/start

brctl show


Hit the limit on upload files so here is brctl settings -

Running
bridge name bridge id STP enabled interfaces
virbr0 8000.000000000000 yes
xenbr0 8000.feffffffffff no peth0
vif0.0

Off
bridge name bridge id STP enabled interfaces
virbr0 8000.000000000000 yes



Any input would be appreciated.

Thanks

Attached Files

	bridge.on.txt (2.5 KB, 7 views)
	bridge.off.txt (1.4 KB, 9 views)
	netstat.txt (417 Bytes, 5 views)

Did you install KVM on this machine and then went back to Xen? I suspect KVM interfered with the virtual adapter that Xen uses and broke it. From experience I have found the less you do with Dom0 within Xen the better, Xen does not like to compete with other tasks and certainly not with other VPS software... most VPS software can be presumptuous in this manner and as KVM and Xen use many of the same utilities I would assume the two could fairly easily conflict.

This is a fresh install of Centos 5.5 and Xen(actually many times)

Just reloaded again last night using all the defaults except selinux disabled.

This time using dhcp, IP6 and allow ssh for the firewall. Same problem, not able to connect to Dom0.

I can always get it to work by running /etc/xen/scripts/network-bridge stop

Without stopping the network bridging all work has to be done on console. Also to allow Centos updates.


Has anybody on this list ever been able to connect to Dom0 ?

I'm considering installing a second NIC on the box to see if it resolves.

I can connect to the Dom0 on my box all the top... you are using DHCP? There should be two adapters, peth0 and eth0 when the network bridge is in operation, you might find you have configured the IP information for the wrong one perhaps?

Connect from the host or the network or both?

Please post -

ifconfig
brctl show
netstat -nr

Also include -

iptables -L -v -n

Thanks

I am not going to paste the iptables configuration for a highly configured live server that has no problems with it, other then a special SSH chain there is nothing special going on with my iptables configurations. Also "iptables -nvL" is a more general way of displaying it. And yes I can configure to my VPS over the Internet with ease, there is no "host" network on my Xen configuration, there is only the bridged network, however the server can talk across the public network to the VPS that is hosted on it (tho technically speaking all that is really happening is the traffic is bouncing back to the server from the network card).

I was able to get this fixed after working with the xen mailing list direct

Basically disable xen from doing the networking bridging and leaving it to the OS

http://wiki.libvirt.org/page/Networking

If using Xen it is recommended to disable its network munging by editing /etc/xen/xend-config.sxp and changing the line

(network-script network-bridge)
To be

(network-script /bin/true)

# cat > ifcfg-eth0 <<EOF
DEVICE=eth0
HWADDR=00:16:766:C9:45
ONBOOT=yes
BRIDGE=br0
NM_CONTROLLED=no
EOF


# cat > ifcfg-br0 <<EOF
DEVICE=br0
TYPE=Bridge
BOOTPROTO=dhcp
ONBOOT=yes
DELAY=0
NM_CONTROLLED=no
EOF

# 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

Works fine, lasts a long time...