Open Stack

Hi!
I think that the DHCP server does not work for the laptop because it only server MAC:IP pairs configured by Neutron. You can confirm by stealing a MAC address configured to an instance. Stop it and try dhclient ;-).

However, I'm not enough of a Neutron guru to guarantee you that you will be able to communicate everywhere when you patch in like this. Mainly in Neutron DVR, there is some filtering and rewriting being done in OpenvSwitch.
Tomas

-----Original Message-----
From: Ali Volkan Atli [mailto:Volkan.Atli at argela.com.tr] 
Sent: Monday, July 17, 2017 12:46 PM
To: openstack at lists.openstack.org
Subject: [Openstack] dhcp namespace and vert pairs?


I have a VM launched using OpenStack and a laptop added directly into integration bridge using ovs-vsctl add-port option. Also I used ./stack script from devstack github and my local.conf as below:

    argela at cloud:~$ sudo ovs-vsctl add-port br-int eno4 tag=1

    argela at cloud:~$ sudo ovs-vsctl show
    ...
    Bridge br-int
        Port "tapb22e0bb6-c6"
            tag: 1
            Interface "tapb22e0bb6-c6"
                type: internal
        Port "eno4"
            tag: 1
            Interface "eno4"
   ...

    root at cloud:~/devstack# cat local.conf
    [[local|localrc]]
    ADMIN_PASSWORD=admin
    DATABASE_PASSWORD=$ADMIN_PASSWORD
    RABBIT_PASSWORD=$ADMIN_PASSWORD
    SERVICE_PASSWORD=$ADMIN_PASSWORD

    FLAT_INTERFACE=eno1,eno3,eno4,eno5,eno6,eno7,eno8

    # Fixed and floating subnets
    FIXED_RANGE=10.254.1.0/24
    FLOATING_RANGE="192.168.111.0/24"

When I run dhclient in the instance launched from OpenStack, I can see the bootp/dhcp messages in the dhcp network space, but when I tried to run dhclient in external laptop, I can only see the discover message in dhcp namespace, the laptop cannot get any response. So VM can get an IP address but the laptop cannot. I checked the iptables and flow-entries in OvS but I could not understand why laptop cannot get response from dhcp namespace.

    stack at cloud:~/devstack$ ip netns list
    qrouter-b1285ebf-d7f6-4af5-bf13-54356b073ca2
    qdhcp-f0d79126-a5f2-46a6-90a9-b0e2f805f93d

dhcp namespace iptable is as follows:

    root at cloud:~/devstack# iptables -S
    -P INPUT ACCEPT
    -P FORWARD ACCEPT
    -P OUTPUT ACCEPT
    -N neutron-dhcp-age-FORWARD
    -N neutron-dhcp-age-INPUT
    -N neutron-dhcp-age-OUTPUT
    -N neutron-dhcp-age-local
    -N neutron-filter-top
    -A INPUT -j neutron-dhcp-age-INPUT
    -A FORWARD -j neutron-filter-top
    -A FORWARD -j neutron-dhcp-age-FORWARD
    -A OUTPUT -j neutron-filter-top
    -A OUTPUT -j neutron-dhcp-age-OUTPUT
    -A neutron-filter-top -j neutron-dhcp-age-local

One more question. I can see that there are namespaces created by OpenStack, qrouter and qdhcp. I know that if I want to connect the namespace to OvS, I need to create Veth Pairs (e.g. ip link add veth0 type veth peer name veth1), and then assign one peer to a namespace (e.g. ip link set veth1 netns blue) and the other into OvS. But for OpenStack I also cannot any vert pairs. How did OpenStack connect the dhcp namespace to OvS? How can I find out which "vert peer" the dhcp namespaces use.

Hope someone answers. Thanks in advance.

- Volkan

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