From: tuqiang <tu.qiang35(a)zte.com.cn&gt; We try to update vlan tag by running virsh update-device command, libvirtd will report ovs-vsctl arguments error. Vlan tag update funtion does't consider the xml with no vlan configured circumstances. The steps to reproduce the problem: 1 define and start domain with its vlan configured as: <interface type='bridge'> <mac address='52:54:00:9e:bb:ac'/> <source bridge='ovs-br0'/> <vlan> <tag id='10'/> </vlan> <virtualport type='openvswitch'> </virtualport> <target dev='vnet4.0'/> <model type='virtio'/> <driver name='vhost'/> </interface> 2 define and run virsh update-device command with no vlan configured as: <interface type='bridge'> <mac address='52:54:00:9e:bb:ac'/> <source bridge='ovs-br0'/> <virtualport type='openvswitch'> </virtualport> <target dev='vnet4.0'/> <model type='virtio'/> <driver name='vhost'/> </interface> #virsh update-device dom-id novlan.xml 3 virsh command returned error, and we got an error in libvirtd.log: error : virCommandWait:2584 : internal error: exit status 1: ovs-vsctl: 'set' command requires at least 3 arguments . Child process (ovs-vsctl --timeout=5 -- --if-exists clear Port vnet4.0 tag -- --if-exists clear Port vnet4.0 trunk -- --if-exists clear Port vnet4.0 vlan_mode -- --if-exists set Port vnet4.0) unexpected error : virNetDevOpenvswitchUpdateVlan:540 : internal error: Unable to set vlan configuration on port vnet4.0 Signed-off-by: Tu Qiang <tu.qiang35(a)zte.com.cn&gt; Signed-off-by: Yi Wang <wang.yi59(a)zte.com.cn&gt; --- src/util/virnetdevopenvswitch.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c index bcdb7c4..227c040 100644 --- a/src/util/virnetdevopenvswitch.c +++ b/src/util/virnetdevopenvswitch.c @@ -605,8 +605,10 @@ int virNetDevOpenvswitchUpdateVlan(const char *ifname, virCommandAddArgList(cmd, "--", "--if-exists", "clear", "Port", ifname, "tag", "--", "--if-exists", "clear", "Port", ifname, "trunk", - "--", "--if-exists", "clear", "Port", ifname, "vlan_mode", - "--", "--if-exists", "set", "Port", ifname, NULL); + "--", "--if-exists", "clear", "Port", ifname, "vlan_mode", NULL); + + if (virtVlan && virtVlan->nTags > 0) + virCommandAddArgList(cmd, "--", "--if-exists", "set", "Port", ifname, NULL); virNetDevOpenvswitchConstructVlans(cmd, virtVlan); -- 1.8.3.1