[Openstack-operators] Instances not getting DHCP Lease

Divneet Singh divneetsingh.ml at gmail.com
Sat Sep 2 07:57:37 UTC 2017

>What I usually do, and this might not be easiest/best, is, given you
>do have console access, to manually set the IP in the cirrus node.

>Then I enter the ip name space for the dhcp server on the network node
>(sudo ip netns exec qdhcp-<thenetwork> bash), and see if I can ping
>the cirrus node and vice-versa, things like that. Making sure to add a
>security group rule to at least allow ICMP. See if you can at least
>get an arp entry for the virtual machine's IP.

>Usually if there is no connectivity at all it's b/c a vlan is missing
>for the physical interface on the switch (not sure how your deployment
>is setup), or the also neutron configuration settings are incorrect in
>terms of bridge mappings and such, usually something simple like that.

>Another option is to reboot or retry dhcp on the cirrus vm and tcpdump
>on the physical interface the dhcp server is on and watch for dhcp
>traffic, and you could do that on the compute node as well, looking
>for both request and response, again to validate basic connectivity.

>If you still are having issues, let us know how you deployed openstack
(distro?) and what kind of network you are using (vxlan, vlan?),
whether it's linux bridge or ovs, things like that.


I have deployed the nodes using a virtual box & set up nat 2 nat networks ,
configured the neutron service according to self service network guide . I
have doubled checked the neutron configuration . I do agree to fact the

Although i can't make out whether there is connectivity between the nodes.
I get the following output when i run the tcp dump on the controller node .

listening on enp0s3, link-type EN10MB (Ethernet), capture size 262144 bytes
12:48:26.488533 IP > Flags [P.], seq
1408700411:1408700519, ack 23895, win 40080, length 108
12:48:26.488719 IP > Flags [P.], seq
108:144, ack 1, win 40080, length 36

Output on the compute node .

listening on enp0s3, link-type EN10MB (Ethernet), capture size 262144 bytes
12:59:21.558954 IP > Flags [P.], seq
1404672109:1404672297, ack 639164055, win 312, options [nop,nop,TS val
677134 ecr 715780], length 188
12:59:21.559252 IP > Flags [.], ack
188, win 1444, options [nop,nop,TS val 715791 ecr 677134], length 0
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