L2 : Networking: bridge and virtual network

Various tool:

brctl ( bridge-utils package) create bridge,  it will be attach to a "host interface" and will have an IP@, tipical usage: mgt bridge or second interface/back up link

virsh ( libvirt ) create virtual network, internal vbridge, only between VM.

[root@hp8300 me]# nmcli device

[root@hp8300 me]# nmcli connection

br0 is connected thru eno1 to the LAN  ( used for management )

Create a virtual network with virsh

main directory: /etc/libvirt/qemu/networks/

virsh net-define virbr1.xml
virsh net-start virbr1
virsh net-autostart virbr1

[root@hp8300 vmx]# virsh help | grep net-

    net-autostart                  autostart a network
    net-create                     create a network from an XML file
    net-define                     define an inactive persistent virtual network or modify an existing persistent one from an XML file
    net-destroy                    destroy (stop) a network
    net-dhcp-leases                print lease info for a given network
    net-dumpxml                    network information in XML
    net-edit                       edit XML configuration for a network
    net-event                      Network Events
    net-info                       network information
    net-list                       list networks
    net-name                       convert a network UUID to network name
    net-start                      start a (previously defined) inactive network
    net-undefine                   undefine a persistent network
    net-update                     update parts of an existing network's configuration
    net-uuid                       convert a network name to network UUID