My setup has 3 networks: 1xIB,1x10Gbit+1Gbit for ovirt-management.

The ovirt network does not have any trouble, it is always there.
I was trying to rename or remove my IB network which was used for VM migrations.
I was using web-GUI, which was removing IB0 network w/o problem. After removal the hosts where ok. Then I put them to maintenance mode. To refresh iptables rules I did reinstall. then reinstall was failing with message that IB0 not attached to any interface. But IB0 interface is not possible to attach it is already deleted and not visible in any network dialog.
After creating interface with the same name everything is online now.
My current interface list is following:
virsh -r net-list
Name                 State      Autostart     Persistent
--------------------------------------------------
;vdsmdummy;          active     no            no
vdsm-cls10G          active     yes           yes
vdsm-IB0             active     yes           yes
vdsm-ovirtmgmt       active     yes           yes

On this host the IB0 is not atached to any interface, I wondered, if it should show up in the net list?

I think the GUI does not rename/remove the interface from the DB. Some constrain keeps still IB0 in DB.

*********************************************************** Dr. Arman Khalatyan              eScience -SuperComputing 
 Leibniz-Institut für Astrophysik Potsdam (AIP)            
 An der Sternwarte 16, 14482 Potsdam, Germany              
***********************************************************

On Sun, Dec 28, 2014 at 10:31 AM, Moti Asayag <masayag@redhat.com> wrote:

----- Original Message -----
> From: "Arman Khalatyan" <arm2arm@gmail.com>
> To: "users" <users@ovirt.org>
> Sent: Wednesday, December 24, 2014 1:22:43 PM
> Subject: [ovirt-users] Unable to reinstall hosts after network removal.
>
> Hello,
> I have a little trouble with ovirt 3.5 on CentOS6.6:
> I was removing all networks from all hosts.

Did you use the setup networks dialog from the UI in order to remove those networks ?
Or have you removed those networks from the host directly (where you should used the:
1. virsh net-destroy 'the-network-name'
2. virsh net-undefine 'the-network-name'
)

can you report the output of 'virsh -r net-list' ?

> Then after removing network from data center the hosts went to unusable.

What was the host's status prior to removing its networks ? Was it up ?

> Every time after reinstall the host claims that the network is not
> configured, but it s already removed from network tab in DC.

What is the missing network name ? Is it 'ovirtmgmt' ?

> Where from it gets the old configuration? the old interfaces also restored
> every time on the reinstalled hosts.

The hosts via vdsm reports their network configuration via the 'getCapabilities' verb
of vdsm. You can try running it on the host:

vdsClient -s 0 getVdsCaps

and examine the nics / neworks / bridges / vlans / bonds elements.

> Which DB table is in charge of dc-networks?
>

The retrieved information from vdsm is reported to 'vds_interace' table.
The dc networks are stored in 'networks' table and networks attached to
clusters are stored in network_cluster table.

I wouldn't recommend on deleting entries from the tables directly. There are
certain constraints which shouldn't be violated, i.e. the management network
'ovirtmgnt' is blocked for removal from the engine.

> Thanks,
> Arman.
>
>
> ***********************************************************
> Dr. Arman Khalatyan eScience -SuperComputing Leibniz-Institut für Astrophysik
> Potsdam (AIP) An der Sternwarte 16, 14482 Potsdam, Germany
> ***********************************************************
>
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