Re: [ovirt-users] newbie questions on networking

Randy this flaky layer two problem reeks of a possible MTU situation between your oVirt switches and your physical switches. > On May 7, 2018, at 3:59 PM, Dominik Holler <dholler(a)redhat.com&gt; wrote: > > On Mon, 7 May 2018 11:43:51 -0700 > "Rue, Randy" <randyrue(a)gmail.com&gt; wrote: > >> I've sort of had some progress. On Friday I went to the dentist and >> when I returned, my VM could ping google. >> >> I don't believe I changed anything Friday morning but I confess I've >> been flailing on this for so long I'm not keeping detailed notes on >> what I change. And as I'm evaluating oVirt as a possible replacement >> for our production xencenter/xenserver systems, I need to know what >> was wrong and what fixed it. >> >> I reinstalled the ovirt-engine box and two hosts and started again. >> The only change I've made beyond the default is to remove the >> no-mac-spoofing filter from the ovirtmgmt vNIC profile so there are >> no filters applied. At this point I'm back to an ubuntu LTS server VM >> that again, is getting a DHCP IP address, nameserver entries in >> resolv.conf, and "route" shows correct local routing for addresses on >> the same subnet and the correct gateway for the rest of the world. >> The VM is even registering its hostname in our DNS correctly. And I >> can ping the static IP of the host the VM is on, but not the subnet >> gateway or anything in the real world. >> > Can you ping the DHCP server? > >> Two things I haven't mentioned that I haven't seen anything in the >> docs about. My ovirt-engine box is on a different subnet than my >> hosts, and my hosts are using a bonded pair of physical interfaces >> (XOR mode) for their single LAN connection. > Was the bond created before adding the hosts to oVirt, or after adding > the hosts via oVirt web UI? > If the switch requires configuration for the bond, is this applied? > Can you check if the VM can ping the getaway, if you use a simple > Ethernet connection instead of the bond? > >> Did I miss something in the docs where these are a problem? >> >> Dominik, to answer your thoughts earlier: >> >> * name resolution isn't happening at all, the VM can't reach a DNS >> server >> >> * I don't manage the data center network gear but am pretty sure >> there's no configuration that blocks traffic. This is supported by my >> temporary success on Friday. And we also have other virtualization >> hosts (VMWare hosts) in the same subnet, that forward traffic to/from >> their VMs just fine. >> > OK, L3 seems to work now sometimes. > >> * tcpdump on the host's ovirtmgmt interface is pretty noisy but if I >> grep for the ubuntu DDNS name I see a slew of ARP requests. I can see >> pings to the host's IP address, and attempts to SSH from the VM to >> its host. Any attempt to touch anything past the host shows nothing >> on any interface in tcpdump, not a ping to the subnet gateway, not an >> SSH attempt, not a DNS query or a ping to known IP address. >> > The outgoing ARP requests looks like the traffic of the VM is forwarded > to ovirtmgmt. > Do you see ARP reply to the VM? > Maybe the VM fails to get the MAC address of the gateway. > >> * hot damn, here's a clue! I can ping other oVirt hosts! (by IP only) >> I also tried pinging the ovirt-engine box, wasn't surprised when that >> failed as the VM would need to reach the gateway to get to the >> different subnet. >> >> So it appears that even though I've set up the ovirtmgmt network >> using defaults, and it has the "VM Network" option checked, my >> logical network is still set to only allow traffic between the VMs >> and hosts. >> >> What am I missing? >> >> -randy > _______________________________________________ > Users mailing list > Users(a)ovirt.org > http://lists.ovirt.org/mailman/listinfo/users >