yahoo-eng-team team mailing list archive

[OpenStack Infra <1668145@xxxxxxxxxxxxxxxxxx>]

Reviewed:  https://review.openstack.org/438171
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=723169245978db29fdd42af18d5958e76c23a0fe
Submitter: Jenkins
Branch:    master

commit 723169245978db29fdd42af18d5958e76c23a0fe
Author: Harald Jensas <harald.jensas@xxxxxxxxx>
Date:   Sat Feb 25 11:05:22 2017 +0100

    Only add "on-link" routes for L2 adjacent subnets
    
    When multiple subnets exist on a single network, the
    DHCP agent adds on-link routes for all of them since
    they are in the same L2 network.  If either subnet
    has a segment_id it can only be considered as on-link
    if they match, else we should not include a subnet
    route.
    
    These extra routes are optional anyways according to
    RFC 3442, but were added for the use case when all of
    the subnets are considered adjacent, which allows
    instances to bypass the router and communicate directly.
    
    Closes-Bug: #1668145
    Change-Id: Iae889e9226a61059cd4f3d37fbe48d013b7a3482
    Implements: blueprint tripleo-routed-networks-deployment


** Changed in: neutron
       Status: In Progress => Fix Released

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to neutron.
https://bugs.launchpad.net/bugs/1668145

Title:
  [RFE] Allow operator control of "on-link" routes for subnets in the
  same Neutron network

Status in neutron:
  Fix Released

Bug description:
  When adding multiple subnets on a single network the dhcp agent will
  set dhcp-options to advertise "on-link"/"same-segment" classless
  static routes to all the subnets.

  A couple of use cases where these on-link/link-local routes are
  undesirable:

  a) When using Ironic for baremetal provisioning the baremetal nodes
  might be on a different L2 broadcast segment with a DHCP-relay.

  b) In a Spine-Leaf deployed Openstack, a pattern is to use identical
  VLAN id's for provider networks in each leaf. Same VLAN id, but
  different L2 domain and different IP subnets.

  
  IMO, creating these routes are a bit opinionated. If we don't create them by default, the operator/end-user is fully able to create them if they are desired on a per-subnet basis. But since we decided these "should" be there, the operator loose the ability to control this.

To manage notifications about this bug go to:
https://bugs.launchpad.net/neutron/+bug/1668145/+subscriptions