[ovs-discuss] ovs-vsctl command in citrix xenserver

[Ben Pfaff]

On Thu, Dec 26, 2013 at 10:36:23AM +0900, Soyoung Jeong wrote:
> Hello,
> I'm testing ovs command in citrix xenserver 6.0.2, and I found the
> following command executed when creating vlan object (with vlan tag 1000 on
> the eth2) in xenserver:
> 
> [root at nclcst301 debug]# ovsdb-tool show-log /etc/openvswitch/conf.db
> .....
> record 714: 2013-12-20 17:09:02 "ovs-vsctl: /usr/bin/ovs-vsctl --timeout=20
> -- --with-iface --if-exists del-port eth2 -- --may-exist add-br xenbr2 --
> --may-exist add-port xenbr2 eth2 -- set Bridge xenbr2
> "other-config:hwaddr=\"98:4b:e1:67:3d:ec\"" -- set Bridge xenbr2
> fail_mode=standalone -- remove Bridge xenbr2 other_config disable-in-band
> -- br-set-external-id xenbr2 xs-network-uuids
> af7a9da8-ad61-52f5-3755-0fc755964e80;14c2e3a6-d154-0d23-d91d-3fcc6f100f8e;4b93be58-72f8-7867-fbe2-6d3e7fc1cf8d;4580b69a-7e78-19ae-ad5a-bad3419c3543
> -- --if-exists del-br xapi10 -- --may-exist add-br xapi10 xenbr2 1000 --
> br-set-external-id xapi10 xs-network-uuids
> af7a9da8-ad61-52f5-3755-0fc755964e80;14c2e3a6-d154-0d23-d91d-3fcc6f100f8e;4b93be58-72f8-7867-fbe2-6d3e7fc1cf8d;4580b69a-7e78-19ae-ad5a-bad3419c3543
> -- set Interface xapi10 "MAC=\"98:4b:e1:67:3d:ec\"""
> .....
> 
> As far as I know, the above command disconnects eth2 at first (--if-exists
> del-port eth2) .. If it's true, can packet loss happen if other VMs are
> connected to the eth2 for a while?

The removal and addition happen within a single database transaction,
so there should be no packet loss.