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[Armando Migliaccio <1219795@xxxxxxxxxxxxxxxxxx>]

*** This bug is a duplicate of bug 1431105 ***
    https://bugs.launchpad.net/bugs/1431105

I think this can be closed, as it was fixed in:

https://review.openstack.org/#/c/163672/

** This bug has been marked a duplicate of bug 1431105
   dhcp scheduling is racey with first port creation

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https://bugs.launchpad.net/bugs/1219795

Title:
  Inconsistent DHCP port creation

Status in neutron:
  In Progress

Bug description:
  When creating a subnet, the DHCP port is not being created until another
  port is created. That is, unless ports have been created on the network.
  And a call to create a subnet will return before the DHCP port is established
  (if that occurs), which produces a race condition if creating a port immediately after creating the subnet.

  This is easier is explain by example :)

  The following can be run from a shell script to reproduce the issue:

  neutron net-create test_net
  neutron subnet-create test_net 198.18.0.0/24
  neutron subnet-create test_net 2001:db8:abc:123::/64 --ip-version 6
  sleep 5 # just to be sure
  neutron port-list
  # dhcp port has not been created yet
  neutron port-create test_net --name test_port
  # the dhcp port is created after the test_port.
  # apparently before the port-create command returns,
  # as no sleep is needed before the port-list.
  neutron port-list
  # test_port assigned 198.18.0.2 and 2001:db8:abc:123::2
  # dhcp port assigned 198.18.0.3 and 2001:db8:abc:123::3
  neutron port-delete test_port
  neutron net-delete test_net

  neutron net-create test_net
  # this add/remove port before subnet creation causes the dhcp port
  # to be setup when the subnets are created.
  neutron port-create test_net --name test_port
  neutron port-delete test_port
  neutron subnet-create test_net 198.18.0.0/24
  neutron subnet-create test_net 2001:db8:abc:123::/64 --ip-version 6
  sleep 5 # subnet-create returns before the dhcp port is setup
  neutron port-list
  # dhcp port assigned 198.18.0.2 and 2001:db8:abc:123::2
  neutron port-create test_net --name test_port
  neutron port-list
  # test_port assigned 198.18.0.3 and 2001:db8:abc:123::3
  neutron port-delete test_port
  neutron net-delete test_net

  # this creates a condition where if you create the test_port
  # after the subnets without sleeping, the test_port gets the ::2 ipv6
  # address before the dhcp port.
  neutron net-create test_net
  neutron port-create test_net --name test_port
  neutron port-delete test_port
  neutron subnet-create test_net 198.18.0.0/24
  neutron subnet-create test_net 2001:db8:abc:123::/64 --ip-version 6
  neutron port-create test_net --name test_port
  sleep 5 # in order to see the dhcp port
  neutron port-list
  # test_port assigned 198.18.0.3 and 2001:db8:abc:123::2
  # dhcp port assigned 198.18.0.2 and 2001:db8:abc:123::3
  neutron port-delete test_port
  neutron net-delete test_net

  It seems the solution would be to make sure the DHCP port check is performed
  after a subnet is created/updated, and not return until that is completed.
  It doesn't seem like this would be necessary when creating/updating a port.
  (unless it's the DHCP port that's being modified?)

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