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Networking/DHCP questions

 

Hi,

I'm having real trouble setting up networking with OpenStack. I had it partly working a while ago, but now I don't even get an IP address. I followed the main guide, but found it difficult to understand why things were being done - a list of instructions is all very well, but without explanations/background it makes debugging tough (http://docs.openstack.org/folsom/basic-install/content/basic-install_intro.html)

I've got a few questions I hope someone can help me with:

(1) responsibility for networking has mainly moved from nova to quantum. So the new way of doing things is solely in quantum - I can ignore anything network related in nova EXCEPT for metadata? (2) there is a problem with rebooting - the bridges created in the guide don't come up automatically?

If I manually start the bridges and restart all the services I can bring up a virtual machine in the web GUI and see messages in /var/log/syslog - pairs of DHCPDISCOVER/DHCPOFFER. This goes on for some time until the VM gives up:

cloud-init-nonet waiting 120 seconds for a network device.
cloud-init-nonet gave up waiting for a network device.
ci-info: lo    : 1 127.0.0.1       255.0.0.0       .
ci-info: eth0  : 1 .               .               fa:16:3e:14:5a:69
route_info failed

The bridge setup (ovs-vsctrl show):

2df4b128-c977-48e2-aac9-596d386b7af1
    Bridge br-tun
        Port br-tun
            Interface br-tun
                type: internal
        Port patch-int
            Interface patch-int
                type: patch
                options: {peer=patch-tun}
    Bridge br-int
        Port "qr-03033815-f4"
            tag: 1
            Interface "qr-03033815-f4"
                type: internal
        Port br-int
            Interface br-int
                type: internal
        Port patch-tun
            Interface patch-tun
                type: patch
                options: {peer=patch-int}
        Port "qvocd51bf09-06"
            tag: 1
            Interface "qvocd51bf09-06"
        Port "tap5ec829c5-74"
            tag: 1
            Interface "tap5ec829c5-74"
                type: internal
    Bridge br-ex
        Port br-ex
            Interface br-ex
                type: internal
        Port "eth1"
            Interface "eth1"
    ovs_version: "1.4.0+build0"

(3) Interfaces: the "tap" interface seems to be the network node, while the "qr" interface is the controller. (Is this always the case? I'm just matching IP addresses when I do "ifconfig <interface>") The "qvoc" interface is the VM - I think - it has no IP address?

(4) Connectivity: all three of them are on the br-int bridge, so presumably they should all be able to talk to each other? (This is the same as if they were all plugged into a switch, right?)

(5) Is there a way to see where things are going wrong? It looks like the DHCPOFFER is never reaching the VM, which if they're all connected seems odd. Can I get a trace of packets being dropped or similar?

Iain