[Users] Networking questions (LONG)

Alan Murrell lists at murrell.ca
Fri Jan 10 00:16:21 UTC 2014


Hello Lior,

Thank you for your reply.

Quoting "Lior Vernia" <lvernia at redhat.com>:

> This way the firewall VM will get something like "eth1" for VLAN 1,
> "eth2" for VLAN 200 and so forth, which might be close enough to what
> you described on your previous setup (oVirt currently doesn't allow
> creating VLANs inside VMs). And if I correctly understood your needs it
> will save you the trouble you described below (well, you would need the
> one dummy interface).

That would be doable, except I am not sure if there is a limit to the  
number of vNICs a VM could have and/or if there is an OS-level limit  
to how many?  It is also a bit "messier" IMO, but that is more of a  
personal issue than a technical one, and one I could probably get over  
:-)

When you say that oVirt currently doesn't allow creating VLANs inside  
VMs, are you referring to the use of VLAN interfaces like I describe  
(e.g., "eth1.1", "eth1.2", "eth1.10", etc.)?  If so, is that an oVirt  
limitation, or a KVM one?

I have seen examples where one can create a "Trunk" with KVM and Open  
vSwitch, and I thought for some reason oVirt used Open vSwitch, but  
none of the commands I tried from the examples were found.  A check of  
<http://www.ovirt.org/Features/Node/OpenVSwitchSupport> shows that  
indeed there does not appear to be any integration yet, and it is only  
60% done :-(

With regards to using the dummy interfaces, I realised I probably do  
not need to add them to a bridge, since they would be physical NICs in  
production (this is just for testing).  I initially did create the  
"ovirtvm" bridge before I realised that, but have made them  
"stand-alone" NICs with no IPs attached to them, but they are not  
"green" in oVirt when I try to attach my logical networks to them  
under "Networks > Hosts > vmhost01 > Setup Host Networks".

When I am in "Setup Host Networks", I see my dummy interfaces, but  
they have a red dot instead of a green one (like what "eth0" has). I  
can my logical networks to them, but the "Network Device Status" has a  
red arrow pointing down.  Here are my ifcfg-dummy* files:

--- ifcfg-dummy0 ---
DEVICE=dummy0
ONBOOT=yes
TYPE=Ethernet
DELAY=0
BOOTPROTO=none
NM_CONTROLLED=no
STP=no
--- ifcfg-dummy0 ---

My "ifcfg-dummy1" is identical, except of course it has  
"DEVICE=dummy1" in it.  The interfaces do come up on the host, but as  
I said, in "Setup Host Networks" they have a red dot instead of a  
green one.  Perhaps I do need to assign an IP?  I can maybe assign a  
"dummy" one (i.e., one that I would never use)?

-Alan



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