CentOS 8.x Creating bridge interfaces (br0) for virtual hosts to use shared interface

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CentOS 8.x Creating bridge interfaces (br0) for virtual hosts to use shared interface

To create bridge interfaces in CentOS 8.0 (or even 7.0) almost same settings as described in older Creating bridge interfaces (br0) for virtual hosts to use shared interface, with an additional 'NAME=' parameter in both interface configuration files. Example configuration files for CentOS 8.0 bridge are:

In /etc/sysconfig/network-scripts/ifcfg-br0

   NAME="br0"
   DEVICE="br0"
   TYPE="Bridge"
   BOOTPROTO="dhcp"
   ONBOOT="yes"

In /etc/sysconfig/network-scripts/ifcfg-<interface-name>

   NAME="<interface-name>"
   DEVICE="<interface-name>"
   TYPE="Ethernet"
   BOOTPROTO="none"
   ONBOOT="yes"
   BRIDGE="br0"

where <interface-name> can be eth0, enp0s1, eno1, etc.

If you want to specify additional settings such as for IPV6 they should all go in ifcfg-br0 file only. Example settings that can go to ifcfg-br0 are:

DEFROUTE=yes
IPV4_FAILURE_FATAL=no
IPV6INIT=yes
IPV6_AUTOCONF=yes
IPV6_DEFROUTE=yes
IPV6_FAILURE_FATAL=no
IPV6_ADDR_GEN_MODE=stable-privacy

These should be removed from ifcfg-<interface-name> file to avoid duplication.

For changes to take effect restart NetworkManager service using:

systemctl stop NetworkManager
systemctl start NetworkManager

Validate that bridge is having ip address and not interface:

nmcli connection show
nmcli connection show <ethernet-interface> | grep br0

Should show

connection.master: br0

Older information on this can be found at:

• Creating bridge interfaces (br0) for virtual hosts to use shared interface

Refer:

• https://computingforgeeks.com/how-to-create-a-linux-network-bridge-on-rhel-centos-8/

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