We can add a new virtual bridge through the Proxmox GUI or CLI. Virtual bridges are created at the node level. So select the node which will have the bridge and then click on Network to see the list of existing configured virtual bridges and physical network interfaces installed in that node. The following figure shows the Network option for our node pmx-01 in our example cluster:

Note that if the GUI is used to create a bridge, then the node will need to be restarted to apply the configuration. This is because a new network interface configuration through the GUI gets written in /etc/network/interfaces.new, and only by rebooting does the new configuration get permanently written in /etc/network/interface. The following screenshot shows the pending change information after creating a new bridge named vmbr1:

To revert the changes before a reboot is done, we can simply click on the Revert changes button.

To create a new bridge through the GUI, we need to click on Create under Network, and then we need to select the Linux Bridge option to open the bridge creation dialog box, as shown in the following screenshot: