Bug 1212168

The event should also be accessible via the python bindings.

event-test from /usr/share/doc/libvirt-python should show this event
when a device is attached to a domain:
myDomainEventDeviceAddedCallback: Domain f21(3) device added: net1


+++ This bug was initially created as a clone of Bug #1206114 +++

it seems there is no event that allows libvirt users to detect an attached device (while there is one for detached).

My testing was simply:

# virsh event --loop --all

while I was trying to attach a new device as showed in the 1179138 report.



+++ This bug was initially created as a clone of Bug #1179138 +++

Description:
virt-manager does not show the new added hot-plug devices immediately after virsh command attach device successfully，

Product version
virt-manager-1.1.0-10.el7.noarch
libvirt-1.2.8-11.el7.x86_64
qemu-kvm-rhev-2.1.2-17.el7.x86_64
3.10.0-220.el7.x86_64

How producible
100%

Steps:
1. Prepare a running guest, works well, check the network device in guest and virt-manager
# virsh list
 Id    Name                           State
----------------------------------------------------
 7     rhel7                          running

2. Dumpxml guest for interface list, also checks it in guest
# virsh dumpxml rhel
...
 <interface type='network'>
      <mac address='52:54:00:c6:3b:95'/>
      <source network='default' bridge='virbr0'/>
      <bandwidth>
        <inbound average='1000' peak='5000' burst='1024'/>
        <outbound average='128' peak='256' burst='256'/>
      </bandwidth>
      <target dev='vnet2'/>
      <model type='virtio'/>
      <driver name='vhost' queues='5'/>
      <link state='down'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x10' function='0x0'/>
    </interface>
...

# virsh domiflist rhel7
Interface  Type       Source     Model       MAC
-------------------------------------------------------
vnet2      network    default    virtio      52:54:00:c6:3b:95

in guest:
# lspci |grep Eth
00:10.0 Ethernet controller: Red Hat, Inc Virtio network device

2. Prepare a network xml, attach it to the guest
# cat /tmp/network1.xml
 <interface type='network'>
      <mac address='52:54:00:b0:8d:2c'/>
      <source network='default' bridge='virbr0'/>
      <target dev='vnet0'/>
      <model type='rtl8139'/>
    </interface>

# virsh attach-device rhel7 /tmp/network1.xml
Device attached successfully

3. Recheck the guest interface list and dumpxml to confirm the network device has been hot-plugged to guest success
# virsh domiflist rhel7
Interface  Type       Source     Model       MAC
-------------------------------------------------------
vnet2      network    default    virtio      52:54:00:c6:3b:95
vnet3      network    default    rtl8139     52:54:00:b0:8d:2c

# virsh dumpxml rhel
...
<interface type='network'>
      <mac address='52:54:00:c6:3b:95'/>
      <source network='default' bridge='virbr0'/>
      <bandwidth>
        <inbound average='1000' peak='5000' burst='1024'/>
        <outbound average='128' peak='256' burst='256'/>
      </bandwidth>
      <target dev='vnet2'/>
      <model type='virtio'/>
      <driver name='vhost' queues='5'/>
      <link state='down'/>
      <alias name='net0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x10' function='0x0'/>
    </interface>
    <interface type='network'>
      <mac address='52:54:00:b0:8d:2c'/>
      <source network='default' bridge='virbr0'/>
      <target dev='vnet3'/>
      <model type='rtl8139'/>
      <alias name='net1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </interface>
...

4. in guest, network exist
# lspci |grep Eth
00:03.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8100/8101L/8139 PCI Fast Ethernet Adapter (rev 20)  ----> the is the new added hot-plug network device
00:10.0 Ethernet controller: Red Hat, Inc Virtio network device

5. check with virt-manager for the new added hot-plug network interface device, click "Show virtual hardware details" menu.
the new added NIC device doest not shown, only the old one can be seen.

6. Close virt-manger window and open it again,  or restart libvirtd, the new added hot-plug devices can be seen from virt-manger.

Additional info:
The same issue also hit on hot-plug for disk, console, usb hostdev devices.

Actual result:
Although, virsh command has attached device successfully, but virt-manager does not sync with guest new added hot-plug devices immediately. It is abnormal.

Expected result:
Virt-manage can sync with virsh command immediately for hot-plug device attach.

--- Additional comment from Ján Tomko on 2015-04-04 19:21:28 CEST ---

Upstream patches proposing the VIR_DOMAIN_EVENT_ID_DEVICE_ADDED event:
https://www.redhat.com/archives/libvir-list/2015-April/msg00183.html
and adding it to the python bindings:
https://www.redhat.com/archives/libvir-list/2015-April/msg00186.html

Note that both the new event and DEVICE_REMOVED are only emitted by the qemu driver.