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To learn a little about OpenStack, a have installed 3 VMs using libvirt/KVM. I followed the http://docs.openstack.org/juno/install-guide/install/yum/content/

I am using CentOS 7, OPenStack Juno and neutron with openvswitch. One VM is the controller, the other is network node and the third is compute node. I am using a cirros image (cirros-0.3.3-x86_64).

Right now I can start an instance but DHCP does not work. I can configure manually the IP DHCP allocates and it works, I can access the instance using ssh from outside and also can access external network from the instance.

I found that the instance DHCP request is reaching network node using the wrong interface:

[root@network neutron]# ip netns
qrouter-89fe919a-0659-4e18-a609-aa698a110c9c
qdhcp-2a920ddf-60ac-4e9f-8731-ca64b02f37df

[root@network neutron]# ip netns exec qrouter-89fe919a-0659-4e18-a609-aa698a110c9c ip link
1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
11: qr-27520527-5c: <broadcast,multicast,up,lower_up> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT
link/ether fa:16:3e:b0:3d:2c brd ff:ff:ff:ff:ff:ff
12: qg-79330b81-77: <broadcast,multicast,up,lower_up> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT
link/ether fa:16:3e:56:e3:d2 brd ff:ff:ff:ff:ff:ff

[root@network neutron]# ip netns exec qrouter-89fe919a-0659-4e18-a609-aa698a110c9c tcpdump -n -i qr-27520527-5c
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on qr-27520527-5c, link-type EN10MB (Ethernet), capture size 65535 bytes
(at this point I ran /etc/init.d/S40network start at instance console)
18:38:27.335127 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:63:f5:86, length 290
18:39:27.414937 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:63:f5:86, length 290

"fa:16:3e:63:f5:86" is the instance MAC address.
So the DHCP request reaches the network node, but using the wrong interrface.

Dnsmasq is listening on tap8dc583ac-23 interface that is on qdhcp-XXX namespace.

root@network neutron]# ip netns exec qdhcp-2a920ddf-60ac-4e9f-8731-ca64b02f37df ip link
1: lo: <loopback,up,lower_up> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
9: tap8dc583ac-23: <broadcast,multicast,up,lower_up> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT
link/ether fa:16:3e:69:91:f2 brd ff:ff:ff:ff:ff:ff

As far as I know, the correct interface is tap8dc583ac-23, but there are something very strange maybe on openvswitch configuration.

Thanks for any help

To learn a little about OpenStack, a have installed 3 VMs using libvirt/KVM. I followed the http://docs.openstack.org/juno/install-guide/install/yum/content/

I am using CentOS 7, OPenStack Juno and neutron with openvswitch. One VM is the controller, the other is network node and the third is compute node. I am using a cirros image (cirros-0.3.3-x86_64).

Right now I can start an instance but DHCP does not work.
I can configure manually the IP DHCP allocates and it works, I can access the instance using ssh from outside and also can access external network from the instance.
instance.

[root@network neutron]# ip netns

qrouter-89fe919a-0659-4e18-a609-aa698a110c9c

qdhcp-2a920ddf-60ac-4e9f-8731-ca64b02f37df
 
netns<br>
qrouter-89fe919a-0659-4e18-a609-aa698a110c9c<br>
qdhcp-2a920ddf-60ac-4e9f-8731-ca64b02f37df

[root@network neutron]# ip netns exec qrouter-89fe919a-0659-4e18-a609-aa698a110c9c ip link
 **qrouter-89fe919a-0659-4e18-a609-aa698a110c9c** ip link<br>
1: lo: <loopback,up,lower_up> <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT
 DEFAULT<br> 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 00:00:00:00:00:00<br>
11: qr-27520527-5c: <broadcast,multicast,up,lower_up> **qr-27520527-5c**: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT
 DEFAULT<br>
    link/ether fa:16:3e:b0:3d:2c brd ff:ff:ff:ff:ff:ff
 ff:ff:ff:ff:ff:ff<br>
12: qg-79330b81-77: <broadcast,multicast,up,lower_up> <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT 
 <br>
    link/ether fa:16:3e:56:e3:d2 brd ff:ff:ff:ff:ff:ff
 
ff:ff:ff:ff:ff:ff<br>

[root@network neutron]# ip netns exec qrouter-89fe919a-0659-4e18-a609-aa698a110c9c tcpdump -n -i qr-27520527-5c
 qr-27520527-5c<br>
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
 decode<br>
listening on qr-27520527-5c, link-type EN10MB (Ethernet), capture size 65535 bytes
 (at bytes<br>
**(at this point I ran /etc/init.d/S40network start at instance console)
 console)**<br>
18:38:27.335127 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:63:f5:86, length 290
 290<br>
18:39:27.414937 IP 0.0.0.0.bootpc > 255.255.255.255.bootps: BOOTP/DHCP, Request from fa:16:3e:63:f5:86, length 290
 
290<br>

"fa:16:3e:63:f5:86" is the instance MAC address.
 address.<br>
So the DHCP request reaches the network node, but using the wrong interrface.
 
interrface.

Dnsmasq is listening on tap8dc583ac-23 interface that is on qdhcp-XXX namespace.
 
namespace.

root@network neutron]# ip netns exec qdhcp-2a920ddf-60ac-4e9f-8731-ca64b02f37df ip link
 **qdhcp-2a920ddf-60ac-4e9f-8731-ca64b02f37df** ip link<br>
1: lo: <loopback,up,lower_up> <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT 
 <br>
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
 00:00:00:00:00:00<br>
9: tap8dc583ac-23: <broadcast,multicast,up,lower_up> **tap8dc583ac-23**: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT 
 <br>
    link/ether fa:16:3e:69:91:f2 brd ff:ff:ff:ff:ff:ff
ff:ff:ff:ff:ff:ff<br>