Thanks for the guidance. I put the patch on gerrit:
https://review.openstack.org/#/c/204725/
JN
> On Jul 21, 2015, at 4:59 PM, Ian Wells <ijw.ubu...@cack.org.uk> wrote:
>
> It is useful, yes; and posting diffs on the mailing list is not the way to
> get them reviewed and approved. If you can get this on gerrit it will get a
> proper review, and I would certainly like to see something like this
> incorporated.
>
> On 21 July 2015 at 15:41, John Nielsen <li...@jnielsen.net> wrote:
>> I may be in a small minority since I a) use VXLAN, b) don’t hate multicast
>> and c) use linuxbridge instead of OVS. However I thought I’d share this
>> patch in case I’m not alone.
>>
>> If you assume the use of multicast, VXLAN works quite nicely to isolate L2
>> domains AND to prevent delivery of unwanted broadcast/unknown/multicast
>> packets to VTEPs that don’t need them. However, the latter only holds up if
>> each VXLAN VNI uses its own unique multicast group address. Currently, you
>> have to either disable multicast (and use l2_population or similar) or use
>> only a single group address for ALL VNIs (and force every single VTEP to
>> receive every BUM packet from every network). For my usage, this patch seems
>> simpler.
>>
>> Feedback is very welcome. In particular I’d like to know if anyone else
>> finds this useful and if so, what (if any) changes might be required to get
>> it committed. Thanks!
>>
>> JN
>>
>>
>> commit 17c32a9ad07911f3b4148e96cbcae88720eef322
>> Author: John Nielsen <j...@jnielsen.net>
>> Date: Tue Jul 21 16:13:42 2015 -0600
>>
>> Add a boolean option, vxlan_group_auto, which if enabled will compute
>> a unique multicast group address group for each VXLAN VNI. Since VNIs
>> are 24 bits, they map nicely to the 239.0.0.0/8 "site-local" multicast
>> range. Eight bits of the VNI are used for the second, third and fourth
>> octets (with 239 always as the first octet).
>>
>> Using this option allows VTEPs to receive BUM datagrams via multicast,
>> but only for those VNIs in which they participate. In other words, it is
>> an alternative to the l2_population extension and driver for environments
>> where both multicast and linuxbridge are used.
>>
>> If the option is True then multicast groups are computed as described
>> above. If the option is False then the previous behavior is used
>> (either a single multicast group is defined by vxlan_group or multicast
>> is disabled).
>>
>> diff --git a/etc/neutron/plugins/ml2/linuxbridge_agent.ini
>> b/etc/neutron/plugins/ml2/linuxbridge_agent.ini
>> index d1a01ba..03578ad 100644
>> --- a/etc/neutron/plugins/ml2/linuxbridge_agent.ini
>> +++ b/etc/neutron/plugins/ml2/linuxbridge_agent.ini
>> @@ -25,6 +25,10 @@
>> # This group must be the same on all the agents.
>> # vxlan_group = 224.0.0.1
>> #
>> +# (BoolOpt) Derive a unique 239.x.x.x multicast group for each vxlan VNI.
>> +# If this option is true, the setting of vxlan_group is ignored.
>> +# vxlan_group_auto = False
>> +#
>> # (StrOpt) Local IP address to use for VXLAN endpoints (required)
>> # local_ip =
>> #
>> diff --git a/neutron/plugins/ml2/drivers/linuxbridge/agent/common/config.py
>> b/neutron/plugins/ml2/drivers/linuxbridge/agent/common/config.py
>> index 6f15236..b4805d5 100644
>> --- a/neutron/plugins/ml2/drivers/linuxbridge/agent/common/config.py
>> +++ b/neutron/plugins/ml2/drivers/linuxbridge/agent/common/config.py
>> @@ -31,6 +31,9 @@ vxlan_opts = [
>> help=_("TOS for vxlan interface protocol packets.")),
>> cfg.StrOpt('vxlan_group', default=DEFAULT_VXLAN_GROUP,
>> help=_("Multicast group for vxlan interface.")),
>> + cfg.BoolOpt('vxlan_group_auto', default=False,
>> + help=_("Derive a unique 239.x.x.x multicast group for each "
>> + "vxlan VNI")),
>> cfg.IPOpt('local_ip', version=4,
>> help=_("Local IP address of the VXLAN endpoints.")),
>> cfg.BoolOpt('l2_population', default=False,
>> diff --git
>> a/neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py
>> b/neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py
>> index 61627eb..a0efde1 100644
>> ---
>> a/neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py
>> +++
>> b/neutron/plugins/ml2/drivers/linuxbridge/agent/linuxbridge_neutron_agent.py
>> @@ -127,6 +127,14 @@ class LinuxBridgeManager(object):
>> LOG.warning(_LW("Invalid Segmentation ID: %s, will lead to "
>> "incorrect vxlan device name"), segmentation_id)
>>
>> + def get_vxlan_group(self, segmentation_id):
>> + if cfg.CONF.VXLAN.vxlan_group_auto:
>> + return ("239." +
>> + str(segmentation_id >> 16) + "." +
>> + str(segmentation_id >> 8 % 256) + "." +
>> + str(segmentation_id % 256))
>> + return cfg.CONF.VXLAN.vxlan_group
>> +
>> def get_all_neutron_bridges(self):
>> neutron_bridge_list = []
>> bridge_list = os.listdir(BRIDGE_FS)
>> @@ -240,7 +248,7 @@ class LinuxBridgeManager(object):
>> 'segmentation_id': segmentation_id})
>> args = {'dev': self.local_int}
>> if self.vxlan_mode == lconst.VXLAN_MCAST:
>> - args['group'] = cfg.CONF.VXLAN.vxlan_group
>> + args['group'] = self.get_vxlan_group(segmentation_id)
>> if cfg.CONF.VXLAN.ttl:
>> args['ttl'] = cfg.CONF.VXLAN.ttl
>> if cfg.CONF.VXLAN.tos:
>> @@ -553,9 +561,10 @@ class LinuxBridgeManager(object):
>> self.delete_vxlan(test_iface)
>>
>> def vxlan_mcast_supported(self):
>> - if not cfg.CONF.VXLAN.vxlan_group:
>> + if not (cfg.CONF.VXLAN.vxlan_group or
>> cfg.CONF.VXLAN.vxlan_group_auto):
>> LOG.warning(_LW('VXLAN muticast group must be provided in '
>> - 'vxlan_group option to enable VXLAN MCAST
>> mode'))
>> + 'vxlan_group option or vxlan_group_auto must '
>> + 'be True to enable VXLAN MCAST mode'))
>> return False
>> if not ip_lib.iproute_arg_supported(
>> ['ip', 'link', 'add', 'type', 'vxlan'],
>>
>>
>> __________________________________________________________________________
>> 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
>>
>> __________________________________________________________________________
>> 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
__________________________________________________________________________
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
