Recenly I got confused setting up VLAN and deliver it to my virtualization server(s). I pretty sure my VLAN configuration was working fine and double check the logic is working. I have 10 (Ten) KVM Host, 9 nine of them was properly connected to networks (bridged interface(s)) and the other is having problem because of the bridge interface won’t up.
Problem
The interface can’t connect to existing networks, it can be caused by manual bridge interface creation.
Since the network configuration is a bit differents between EL6 and EL7, nmcli is the key here. Trying to hook up manual configuration by adding brX interface on /etc/sysconfig/networks-script, but no luck.
Have you setup your bridge interface using this old configuration ?
TYPE=Bridge
BOOTPROTO=none
DEFROUTE=no
IPV4_FAILURE_FATAL=no
IPV6INIT=no
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME=br0
DEVICE=br0
ONBOOT=yes
IPADDR=ip.ad.dr.es
PREFIX=24
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
If yes, trying to avoid that, and you should (must!) using nmcli.
To create bridge interface, you just only type this in your servers.
[root@linux ~]# nmcli con add type bridge ifname br0 stp yes priority 36864
[root@linux ~]# nmcli con add type ethernet ifname enp1s0f0 master bridge-br0
Where enp1s0f0 is the interface and change with your real interface name, then br0 is new bridge interface, you can named it, and it’s not always br0 (can be br1, br2, etc). And if you want to see script files inside /etc/sysconfig/networks-script/, it should be like this :
DEVICE=br0
STP=no
TYPE=Bridge
BOOTPROTO=none
DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
NAME=bridge-br0
UUID=411a4a13-caab-41e1-83f5-4d1c31ab0fb4
ONBOOT=yes
IPADDR=192.168.69.25
PREFIX=24
IPV6_PEERDNS=yes
IPV6_PEERROUTES=yes
Conclusion
If you’re using NetworkManager on EL7, you should avoid creating or editing network configuration located under /etc/sysconfig/networks-script. Use NetworkManager (available on nmcli or nmtui) instead of manual.
