Is it a known limitation that the ML2 plugin and associated drivers do not 
properly handle cases where there are multiple agents running on the same host? 
  That is, two or more agents that reside on the same host and both report 
device/interface mappings  for physical networks?    One such setup is a set of 
nodes that are both running an L2 agent and a NIC SRIOV agent.   

We have found two problems specific to this configuration and are wondering if 
these are known limitations, or simply not supported.   

For example, in a configuration where a host has L2, DHCP, and SRIOV agents 
running on it, then:

1)   The DHCP scheduler can schedule a network to be hosted by that DHCP agent 
even if the physical network is only supported by the SRIOV agent and not by 
the L2 agent.  This can end up isolating the DHCP server as it will not have 
access to the underlying physical segment.   This is happening because 
"filter_hosts_with_network_access" in the Ml2Plugin will include the host 
because the SRIOV mech driver reports that it has access to that segment.   

2)   The Segment Plugin "segmenthostmappings" table gets overwritten with 
tuples for whichever agent reports in last.  For example, if the L2 agent has 
physical network mappings for 2 different physical networks (physnet0, 
physnet1), but the SRIOV NIC agent only has 1 physical network reported 
(physnet2), the segmenthostmappings table will have data for only physnet2 if 
the SRIOV NIC agent reported last, or data for only both physnet0 and physnet1 
if the L2 agent reported last.  Data for physical networks belonging to the 
other agent will be erroneously removed as stale entries.

If it has been discussed before is there a plan to address this type of 
configuration?  

Regards.
Allain



Allain Legacy, Software Developer, Wind River
direct 613.270.2279  fax 613.492.7870 skype allain.legacy
350 Terry Fox Drive, Suite 200, Ottawa, Ontario, K2K 2W5

 



__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev

Reply via email to