On 11/13/2012 07:58 PM, Simon Grinberg wrote:
From the summary: "...It supports the following actions without unplugging the Vnic, and it maintains the device address of the Vnic ...."
But in the dialogue section: "If the Vnic is plugged there should be a message on top of the dialog "Please notice, changing Type or MAC will cause unplugging and plugging the Vnic"
Looking at the detailed design indeed any change indeed goes through plug/unplug. Please correct me if I got the above wrong.
Changing the network (rewiring network) is done using new API with VDSM, updateVmInteface.
Therefore plug/unplug won't be executed for any of: 1. Changing the network to other network or disconnecting/unwiring it). 2. Update the name of the VM (db only).
Other changes to VM properties (i.e. MAC address, driver type) will require the plug/unplug. Same goes to any explicit 'unplug' command.
To support real live rewire == "Move a card from one network to another" The sequence should be for wired-plugged card: - Unwire - Change network - Rewire
I would argue that we should actually force the user to perform these steps, but we can do it in one go.
The intention is to use the new API VDSM.libvirtVm.updateVmInteface for performing the network rewire in a single command.
What does it do? I could not find updateVmInteface in vdsm git. Where is this defined? The wiki was updated, you can find it there. http://wiki.ovirt.org/wiki/Feature/DetailedNetworkWiring#VDSM_API
It's critical.
- You can change the interface directly by moving the VM from one network to another - You can do that but toggle the ling state so the VM will be aware.
Which if these two? If you do only the first then it's not the common use case. In most cases you must toggle the link status to the VM. This will cause: 1. Speed negotiation + arp request that also informs the switched about the change 2. In case it's DHCP (which most likely the case for guests) it will trigger new DHCP request.
If you don't baaad things will happen :)
Any other state may change network freely.
To change name - it's just DB, so any state goes
To change type or MAC address (= property), must go through unplug regardless to the wired state So: - Unplug - Change property - Plug
Again should probably ask the user to do these 3 steps so he'll know what he is doing, but we can do it for him with proper warning.
I also wander I do we have to drop the PCI address in the persisted table in this case - loosing the PCI location is redundant and will cause a move to another eth0 number in the guest. On the other hand changing of MAC may break network scripts anyhow - so I don't have a strong argument to keep it.
Another issue: If the nic is there to be use by a hook, then you probably want to allow 'none' network. This may also be useful when allowing to purge a network while it is connected to VMs: unwire on all nics and connect to the none network.
Overall, looking great, and I like the wired vs unplugged that emulate real behavior.
Regards, Simon
----- Original Message -----
From: "Alona Kaplan" <alkaplan@redhat.com> To: engine-devel@ovirt.org, "Simon Grinberg" <sgrinber@redhat.com>, rhevm-qe-network@redhat.com Sent: Tuesday, November 13, 2012 4:46:52 PM Subject: Network Wiring
Hi all,
Please review the wiki and add your comments.
http://wiki.ovirt.org/wiki/Feature/NetworkWiring
Thanks, Alona.
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