[ovirt-users] oVirt / ROM images / PXE

This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --0-108168896-1425672075=:9228 Content-Type: TEXT/PLAIN; format=flowed; charset=ISO-8859-15 Content-Transfer-Encoding: 8BIT Summary: To get oVirt-managed VMs to boot using PXE, I had to replace the rhel6-*.rom files with their ipxe equivalents. Setup: Nodes running CentOS 7, fully current. Engine 3.5.0.1 running on Fedora 19. Storage via NFS. 1GB ethernet network. DHCP server on separate subnet, relying on dhcp-relay switch settings. PXE is our preferred method for installing VMs. We rarely use templates. I recently upgraded our oVirt hypervisor nodes from Fedora 19 to CentOS 7 (where "upgrade" obviously implies a full OS re-installation). I failed to test creating VMs using PXE in this setup because -- and this is crucial -- it worked fine on our non-oVirt CentOS 7 hypervisors, which are managed using virsh and virt-install. So PXE booting a new VM failed. The symptom was the dreaded "dhcp connection timeout" at the seabios prompt. The timout would persist even when I pressed Ctrl-B and re-tried "dhcp net0" several times over the course of the next few minutes. Significantly, existing VMs experienced no DHCP troubles at all, in the sense that dhclient or its equivalent within the VM could get and renew leases as expected. I poked around the forward-delay settings on the oVirt-managed bridges, but they had the same charactistics of the bridges on our non-oVirt hypervisors. Lots of other network-oriented troubleshooting likewise failed. It got to the point that I took one of my oVirt nodes, removed it from oVirt, and reinstalled it with plain CentOS 7. Its physical connections and IP addresses stayed exactly the same. Without oVirt, virt-install used PXE without a hitch. I re-added that machine to the oVirt cluster, and PXE failed once again. I noticed that the BIOS PXE prompt was slightly different in the ovirt and non-ovirt environment, which led me to poke around the ROM images in /usr/share/qemu-kvm. I think the rhel6-*.rom images are those used by oVirt, while the pxe-*.rom images (actually symlinks into ../ipxe/) are used by, e.g., the local virt-install utility. My workaround is to replace the rhel6-*.rom files with the same symlinks used by the pxe-*.rom files: ----- %< ----- # short version of script, minus error checking cd /usr/share/qemu-kvm for NIC in e1000 ne2k_pci pcnet rtl8139 virtio; do mv rhel6-${NIC}.rom rhel6-${NIC}.rom.dist ln -s $(readlink pxe-${NIC}.rom) rhel6-${NIC}.rom done ----- %< ----- Now oVirt VMs can boot from PXE without any issue. I'm wildly curious about what's going on here. -- Paul Heinlein heinlein(a)madboa.com 45°38' N, 122°6' W --0-108168896-1425672075=:9228--