Bridge configuration for KVM Slave
Warning: The actions described below are dangerous and can cause loosing of remote access to the server. It is recommended to have direct access to the server in order to revert the changes back in case of emergency.
If the server is in OVH infrastructure, additional configuration steps are required MAC assigning per IP Address
1. Connect to the slave KVM node via SSH
2. Disable Network Manager as it may interfere with the bridge.
systemctl stop NetworkManager.service systemctl disable NetworkManager.service systemctl enable network.service systemctl start network.service
3. Additionally, it makes sense to review the network configuration
/etc/sysconfig/network-scripts/ifcfg-eth0 and verify that
it is disabled there as well
4. Example of basic network configuration
/etc/sysconfig/network-scripts/ifcfg-eth0 before bridge
interface is configured
TYPE="Ethernet" PROXY_METHOD="none" BROWSER_ONLY="no" BOOTPROTO="none" NM_CONTROLLED=no DEFROUTE="yes" IPV4_FAILURE_FATAL="no" IPV6INIT="yes" IPV6_AUTOCONF="yes" IPV6_DEFROUTE="yes" IPV6_FAILURE_FATAL="no" IPV6_ADDR_GEN_MODE="stable-privacy" NAME="eth0" UUID="8d6f722c-b945-4083-b50e-9661bf62ae5f" DEVICE="eth0" ONBOOT="yes" IPADDR="203.0.113.2" GATEWAY="203.0.113.1" NETMASK="255.255.0.0" DNS1="22.214.171.124" IPV6_PRIVACY="no"
5. Install bridge-utils package:
# yum install bridge-utils
6. Create a copy of the network interface to make changes revertible:
cp /etc/sysconfig/network-scripts/ifcfg-eth0 /root/ifcfg-eth0.orig
Note: It is recommended move non-used configuration files out of the network-scripts/ sub-directory. Be aware that configuration files that starts from ifcfg-* files will be applied, including ifcfg-eth0.backup file.
7. Create the bridge file:
8. Copy network configuration settings from ifcfg-eth0 to ifcfg-br0 file to make it look like below:
DEVICE=br0 TYPE=Bridge BOOTPROTO=static ONBOOT=yes NM_CONTROLLED=no IPV6_AUTOCONF=yes IPV6_DEFROUTE=yes IPV6_PEERDNS=yes IPV6_PEERROUTES=yes IPV6_FAILURE_FATAL=no IPADDR=203.0.113.2 NETMASK=255.255.0.0 GATEWAY=203.0.113.1
9. Edit the
/etc/sysconfig/network-scripts/ifcfg-eth0 as below:
NAME=eth0 DEVICE=eth ONBOOT=yes NM_CONTROLLED=no IPV6INIT=yes IPV6_AUTOCONF=yes BRIDGE=br0
Warning: All parameters should be written with capitalized characters, e.g. BRIDGE=br0 and NOT Bridge=br0
Warning: In case there is a /etc/sysconfig/network-scripts/route-eth0 file (some Hetzner installation has them), the file should be renamed to /etc/sysconfig/network-scripts/route-br0 accordingly.
10. Restart the network service to apply the changes:
service network restart
11. Check that physical interface eth0 is linked to bridged interface br0
brctl show bridge name bridge id STP enabled interfaces br0 8000.001c42717243 no eth0
If there are any errors while configuring bridge check for known
issues on our Support Portal,
Bridge interface does not work on the fresh install
During configuration of bridge interface network fails to restart: bridge support not available: brctl not found