[ovirt-users] Self hosted single server network requirements

[Derek Atkins]

Hi,
+cc back to the list

Mark Steckel <mjs at fix.net> writes:

> Hi Derek,
>
> I solved the first networking issue by changing how Hetzner config'ed
> the /32 on the host. (They were scoping the IP to the gateway which
> was confusing OVirt.)
>
> So now I'm trying to get the /29 working for the VMs... continue below.

Okay..

[snip]
> In the case of Hetzner, they provide the /29 and expect that the gw, the first usable IP of the /29, will be on the host and not the router. At least this is what I get from their docs. Effectively.
>
>      /32           /32
> router ----------- host ----  VMs
>                    /29        /29
>
> To test things I manually created an alias on the ovirtmgmt dev for the /29 gw IP and can ping it from the outside world. So basic routing seems to route for the /29. 
>
> Since OVirt seems to be constrained on the network configs it can deal with, my question is how should I permanently config the /29 gw IP (ie on eth0 or ovirtmgmt) and what do I need to do to set up the /29 IPs for the VMs?

I've never tried setting multiple IPs on my ovirtmgmt bridge on the
host.  But you shouldn't have to do that.  It's a bridge, after all, so
all systems that sit on that bridge (which include your VMs) will be
equivalent.

In my case I have an external router that gets used for both of my
networks (I have a 192.168 network as well as a full class-C but they
share physical infrastructure).  So my host only has a 192.168 address,
my engine is on the class-C, and they talk to each other over the
standard network.

In your case it *SOUNDS* like you need to set up an internal router for
the /29.  The way I would do it would be:

      /32           /32         /29    bridge +--- host (/29)
ISP-Router  ------- internal-router ----------+--- VM   (/29)
                                              +--- VM   (/29)

I don't know if you can actually do this.  If not, your other option
would be:

   /32     bridge +--- host (/32)
router -----------+--- VM Router (/29)  (pfsense?)
                  +--- VM (/29)

This may not work for you, either, depending.

WORST case you may need to manually configure a second IP on the
ovirtmgmt bridge on your host:


   /32     bridge +--- host (/32 + /29)
router -----------+--- VM (/29)
                  +--- VM (/29)

I would do this by manually creating the config file on your host:
/etc/sysconfig/network-scripts/ifcfg-ovirtmgmt:0

> Thanks
> Mark

-derek
-- 
       Derek Atkins                 617-623-3745
       derek at ihtfp.com             www.ihtfp.com
       Computer and Internet Security Consultant