[Users] Re: simple networking? [SOLVED] mostly

Ted Miller tmiller at hcjb.org
Fri Dec 13 04:04:21 UTC 2013

From: users-bounces at ovirt.org <users-bounces at ovirt.org> on behalf of Ted Miller <tmiller at hcjb.org>
Sent: Wednesday, November 27, 2013 12:18 PM
To: users at ovirt.org
Subject: [Users] simple networking?

I am trying to set up a testing network using o-virt, but the networking is
refusing to cooperate.  I am testing for possible use in two different
production setups.

My previous experience has been with VMWare.  I have always set up a single
bridged network on each host.  All my hosts, VMs, and non-VM computers were
peers on the LAN.  They could all talk to each other, and things worked very
well.  There was a firewall/gateway that provided access to the Internet, and
hosts, VMs, and could all communicate with the Internet as needed.

o-virt seems to be compartmentalizing things beyond all reason.
Is there any way to set up simple networking, so ALL computers can see each
Is there anywhere that describes the philosophy behind the networking setup?
What reason is there that networks are so divided?

After banging my head against the wall trying to configure just one host, I
am very frustrated.  I have spent several HOURS Googling for a coherent
explanation of how/why networking is supposed to work, but only fine obscure
references like "letting non-VMs see VM traffic would be a huge security
violation".  I have no concept of what king of an installation the o-virt
designers have in mind, but it is obviously worlds different from what I am
trying to do.

The best I can tell, o-virt networking works like this (at least when you
have only one NIC):
there must be an ovirtmgt network, which cannot be combined with any other
      the ovirtmgt network cannot talk to VMs (unless that VM is running the
      the ovirtmgt network can only talk to hosts, not to other non-VM computers
a VM network can talk only to VMs
      cannot talk to hosts
      cannot talk to non-VMs
hosts cannot talk to my LAN
hosts cannot talk to VMs
VMs cannot talk to my LAN
All of the above are enforced by a boatload of firewall rules that o-virt
puts into every host and VM under its jurisdiction.

All of the above is inferred from things I Googled, because I can't find
anywhere that explains what or how things are supposed to work--only things
telling people WHAT THEY CANT DO.  All I see on the mailing lists is people
getting their hands slapped because they are trying to do SIMPLE SETUPS that
should work, but don't (due to either design restrictions or software bugs).

My use case A:
  * My (2 or 3) hosts have only one physical NIC.
  * My VMs exist to provide services to non-VM computers.
     *  The VMs do not run X-windows, but they provide GUI programs to
non-VMs via "ssh -X" connections.
  * MY VMs need access to storage that is shared with hosts and non-VMs on
the LAN.

Is there some way to TURN OFF network control in o-virt?  My systems are
small and static.  I can hand-configure the networking a whole lot easier
than I can deal with o-virt (as I have used it so far). Mostly I would need
to be able to turn off the firewall rules on both hosts and VMs.

banging head against wall,

I have spent the last three days getting a Centos 6.5 host running under O-virt.

Since the networking was just a small part of this, I am going to open an new thread 
to discuss the Centos 6.5 host setup process.  Look for a thread titled something like
"Centos 6.5 host configuration" if you want the gory details, or want to try if for yourself.

My biggest problem is that the o-virt GUI is apparently incapable of setting
up a bridge in Centos, which turned out to be what I needed.  I had to set up the 
bridge BEFORE adding the host to the ovirt cluster.  If the bridge was not set 
up ahead of time, the whole installation failed completely.

The bridge was only one of a list of things that had to be done ahead of time, in order
for the process to complete correctly.

Ted Miller

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