Neutron ML2: VM instances do not get IP via DHCP with Mellanox

asked 2014-10-17 06:42:04 -0500

nishant80 gravatar image

updated 2014-10-19 23:26:56 -0500

I am trying icehouse and I followed the openstack and mellanox documentation to successfully bring up my own setup. I created Ethernet SR-IOV instances on compute node by following the steps in Mellanox doc:

The VM instances boot and even show the mellanox virtual eth interface that was 'pass-through'ed to it. However, it doesn't get a IP automatically.

I understand that this question is related to a vendor-specific product (mellanox ml2) but I am wondering if there is a generic solution to such issues.

My queries are:

  1. Has anyone seen DHCP working with mellanox ml2 setup?

  2. I have not installed 'Mellanox Dnsmasq driver' as it is mentioned under the 'InfiniBand Network' section of mellanox-icehouse doc whereas I am configuring 'Ethernet Network'. Should I still install 'Mellanox Dnsmasq driver'?

  3. I see this error in /var/log/neutron/dhcp-agent.log on network node - "TRACE neutron.agent.dhcp_agent RemoteError: Remote error: AgentNotFoundByTypeHost Agent with agent_type=DHCP agent and host=controller could not be found". Should I worry about it?

  4. Can I do something else (run some quick tests, check logs etc) to debug this?


  • neutron-dhcp-agent is running on network node.

  • While the VM instance is coming up, it shows this on console for few seconds - "Determing IP information for eth0....". And, finally it says "failed".

Note: I asked the same question on mellanox's comunity web page but so far I did not get a response and hence posting it here too.

EDIT1: I am able to ping between VM instances if I set static IP on them. It's DHCP that I can't seem to get working.

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I guess I need to read more about how DHCP works for VMs in the Linux KVM world. I will get back soon.

nishant80 gravatar imagenishant80 ( 2014-10-22 00:37:56 -0500 )edit

2 answers

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answered 2014-10-24 05:51:56 -0500

Nuriel gravatar image

Yes, the Mellanox ML2 driver works in IceHouse. Try to follow this documentation:

You do need to use the Mellanox provided DHCP driver and basically follow the instructions from the above link. That will also involve updating dnsmasq.

You can also refer to this knowledge base documentation although it involves a slightly different OpenStack managed platform, it is based on the above provided link:

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(1/n) @Nuriel: Thanks for your response.

"Yes, the Mellanox ML2 driver works in IceHouse. Try to follow this documentation:

I have already followed that doc. It doesn't talk much about DHCP configuration

nishant80 gravatar imagenishant80 ( 2014-10-27 00:50:29 -0500 )edit


(it has a broken link on dhcp configuration). I contacted Mellanox folks and they have provided an alternate link -

I will try this link and update soon.

nishant80 gravatar imagenishant80 ( 2014-10-27 00:55:07 -0500 )edit


They also confirmed that mellanox ml2 plugin does not play any role in DHCP. So, I will now focus on the generic topic of making DHCP work for a 'vlan type' network.

Please note that the Mellanox DHCP driver is only used in case of Infiniband (But, I am trying Ethernet).

nishant80 gravatar imagenishant80 ( 2014-10-27 00:55:30 -0500 )edit

(n/n) Looks like the kb link you shared is for infiniband configurations only.

nishant80 gravatar imagenishant80 ( 2014-10-27 00:58:40 -0500 )edit

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Asked: 2014-10-17 06:42:04 -0500

Seen: 945 times

Last updated: Oct 24 '14