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Instances not getting IP through DHCP though IP is being displayed on dashboard [closed]

asked 2015-10-15 01:26:24 -0500

smcas gravatar image

IP are not getting IP through DHCP. When ifconfig is done, no IP is displayed though IP is displayed on dashboard .

Please suggest some solution openstack !!!!

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Closed for the following reason the question is answered, right answer was accepted by smcas
close date 2015-10-27 02:00:28.811697

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answered 2015-10-19 05:29:57 -0500

smcas gravatar image

updated 2015-10-27 01:59:24 -0500

following services should be running on each node and in my setup the all services running on every node which caused the problem. Now it fixed by running only these services.

Network Node

   neutron-dhcp-agent:                     active
    neutron-l3-agent:                       active
    neutron-metadata-agent:                 active
    neutron-openvswitch-agent:              active

Compute Node

openstack-nova-compute active       active
neutron-openvswitch-agent:              active

Controller Node

All nova services except nova-compute
Neutron Server
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answered 2015-10-15 03:02:10 -0500

Cheng Liu gravatar image

updated 2015-10-15 03:04:08 -0500

Try nova console-log <VM-Name> and find if there's any related issue. If there is, you will see some related debug info.

Also, recheck your configurations. I've asked a similar question here, and finally found it was due to a configuration fault. Check the configurations according to your guide or Official Installation Guide at OpenStack Installation Guide for Ubuntu 14.04

If it's still not, search for "Neutron DHCP error" in google. You'll find so many issues related to this. Then try to find problems on your own. Here's suggestions provided by vincent-legoll(and it really helped solving my problem!)

You'll have to use tcpdump starting from inside your VM to see where the DHCP packets get lost. Go from there, then on the compute node, then to the network node (beware of the network namespaces : ip netns XXXXX exec tcpdump [...]). Be careful to take eventual encapsulation (GRE) into account when tcpdump'ing.

You'll have to ensure the dnsmasq processes are properly running(*) on your network node, that they get the DHCP requests, that they answer properly. Then follow the response packet back to the VM, verifying at each network step that they get through.

When you'll have found where they get blocked, you'll know where to search for the cause of that.

(*) they should be configured properly, and running in the right network namespace, etc...

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Hi Cheng, Thanks for the suggestion. Instance log does not show any error and I am clueless about the packets tracing as ip netns does not show any namespace. Dnsmasq process is running on network node. Is there any firewall issue ? Which ports need to be opened on nodes? Please suggest.

smcas gravatar imagesmcas ( 2015-10-16 04:23:08 -0500 )edit

I found a similar problem to yours in this post, mentioning a namespace issue. Hope it works for you.

Cheng Liu gravatar imageCheng Liu ( 2015-10-16 06:21:38 -0500 )edit

Hi Cheng, Thanks for your reply. We have gone through the link but everything is in place according to that. Please suggest some other solution as we are not getting namespaces. Also tell about the rules to be applied for firewall on all nodes.

smcas gravatar imagesmcas ( 2015-10-19 02:16:11 -0500 )edit

Could you paste your neutron and l3 configurations of network node(related files: /etc/neutron/neutron.conf and /etc/neutron/l3_agent.ini) ? Namespace missing doesn't seem like a firewall issue.

Cheng Liu gravatar imageCheng Liu ( 2015-10-19 02:45:49 -0500 )edit

Hi Cheng, Should I send you the changes I have made in these files or the complete files ?

smcas gravatar imagesmcas ( 2015-10-19 04:27:29 -0500 )edit

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Asked: 2015-10-15 01:26:24 -0500

Seen: 8,550 times

Last updated: Oct 27 '15