[ovirt-users] Networking issues with oVirt Guest VM.

[Clint Smith]

Hello,

I have been experimenting with oVirt for the last couple of weeks and I must say it has a lot of nice features.  I really like it, however, I am having a heck of a time getting the guest networking all set up correctly. I am hoping that someone can give me a little guidance in figuring this out.  I apologize in advance if some of my terminology is off,  I am new.

Here is a brief intro to my setup:
I created a Centos 7 VM within a vSphere/ESXI environment and then installed ovirt-engine on it.  I also created another Centos 7 VM and set it up as a host.  I have configured the Cluster and Host via the oVirt Administration Portal.  For simplicity, I am using the default ovirtmgmt network as my only logical network, however I have tried several different schemes with no luck.  I have a DHCP server and a DNS server that are siblings to the oVirt host and the engine.  Both the engine and the host have been upgraded to version 4.0.

The problem:
My thought was that I would have the guest VMs on the oVirt host use my existing DHCP server to get their IP addresses, at least at first.  The problem I am having is that the DHCPACK is not making it back across the ovirtmgmt bridge and on to the guest.  If I tell dhclient(from the guest) to force a Broadcast (by using the –B option) on the DHCP server, it will work.  This is not a solution, just a clue.  Another clue is that ARP replies from the gateway don’t make it back to the machine, preventing pings even when I force the IP.  Lastly, If I turn on Port Mirroring, everything works fine, but it’s my understanding that this is only for debugging purposes.

What I have tried (in no particular order):
Reading the docs
Turning on VLAN tagging.
Installing the mac-spoofing hook, making the configuration changes to the engine, and then turning it on in the VM config.  I also verified that the ‘filterref’ tag was removed using virsh.
Setting up a second logical network on a different subnet, and connecting it to an additional network interface that I added to the host.  On the host, I setup dnsmasq as a DNS and DHCP server.  I got this working up to the point of having the same issues that I was having using the existing DHCP and DNS servers on the ovirtmgmt network.
I have tried various changes to iptables as well as the original settings as well as verified that ebtables is not blocking any traffic.  I did configure iptables for logging and noticed it was dropping some traffic related to DHCP, however it seemed like it was DISCOVER or REQUEST traffic due to the IN, OUT, SRC, and DST variables in the log.  I have viewed the DHCP server logs multiple times and I can see that it is receiving the DISCOVER and the REQUEST from my guests MAC and sending the OFFER and ACK consistently.
Setting SELinux to Permissive
Setting ip_forward to 1
Turning STP ON on the bridge
Changing the bridge delay
Setting up a dhcrelay using dnsmasq (not sure I implemented this right though)
I am really shooting in the dark when it comes to networking because I am learning a lot of this on the fly.   I feel like I must have a misconception about how networking should work with oVirt.  Is my entire approach naïve? Any help/guidance that someone could offer would be much appreciated.

Thanks,
Clint




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