Instances won't obtain IPv6 address and gateway when using Stateful DHCPv6 provided by OpenStack

[Nir Magnezi]

Description of problem:
=======================
I Created an IPv6 subnet with:
1. ipv6_ra_mode: dhcpv6-stateful
2. ipv6_address_mode: dhcpv6-stateful

Version-Release number of selected component (if applicable):
=============================================================
openstack-neutron-2014.2-0.7.b3

How reproducible:
=================
100%

Steps to Reproduce:
===================
1. create a neutron network
2. create an IPv6 subnet:
# neutron subnet-create <IPv6_net_id> 2001:db2::/64 --name usecase2_ipv6_stateles_subnet --ipv6-address-mode dhcpv6-stateful --ipv6_ra_mode dhcpv6-stateful --ip-version 6
3. boot an instance with that network

Actual results:
===============
1. Instance did not obtain IPv6 address
2. default gw is not set

Expected results:
=================
The instance should have IPv6 address a default gw configured.

[Xu Han Peng (xuhanp)]

Nir, can you post the result of "neutron port-list" and "ps -ef| grep dnsmasq" on your environment? Just want to check if dhcp port is created successfully and if dnsmasq works correctly.

[Nir Magnezi (nmagnezi)]

Looks like this issue is a result of: https://bugs.launchpad.net/neutron/+bug/1377985

[Aniruddha Singh Gautam (aniruddha-gautam)]

the patch is identified that enables RADVD to send RA in cases of DHCPv6 stateful usecase and then VM is able to acquire the IP address. whereas in some summit presentations and BP descriptions I found that RADVD is not to be used in case of DHCP stateful, and I am not able to understand the reason behind it and why dnsmasq was design to send RA in DHCP stateful use case. please bear with me I am new to contribute, so can someone educate me on this or provide some helpful references.

[Ihar Hrachyshka (ihar-hrachyshka)]

@Aniruddha, radvd is used for stateful setups too. In that case, it just advertises gateway and tells clients to get both address and additional configuration from DHCP servers.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/144189

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/144630

[OpenStack Infra (hudson-openstack)]

Change abandoned by Aniruddha Singh Gautam (<email address hidden>) on branch: master
Review: https://review.openstack.org/144189
Reason: published the same changes on other branch.

[Aniruddha Singh Gautam (aniruddha-gautam)]

can someone find time to review the patch Change-Id: If685846c0c0f67bf4c40f4f268b9d03bfa2b1654?

[Ihar Hrachyshka (ihar-hrachyshka)]

That makes stateful dhcp broken from user perspective, so targeting to kilo-2.

[Bert JW Regeer (xistence)]

Even when you allow IPv6's ICMP to passthrough the security rules for RA, instances won't know to use DHCPv6 because radvd doesn't have the appropriate flag set:

https://github.com/openstack/neutron/commit/4f3a9135acb561172f7af45bc82739d6dc49f23c

Enables the slaac/slaac+stateful (for DNS), but does not enable stateful at all, this flag is missing:

AdvManagedFlag on;

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/148203

[OpenStack Infra (hudson-openstack)]

Change abandoned by Aniruddha Singh Gautam (<email address hidden>) on branch: master
Review: https://review.openstack.org/144630
Reason: published another patch

[Aniruddha Singh Gautam (aniruddha-gautam)]

can you please review the patch https://review.openstack.org/148203 again, this is my first code change so please bear with me...

[Aniruddha Singh Gautam (aniruddha-gautam)]

updated the https://review.openstack.org/148203

[OpenStack Infra (hudson-openstack)]

Change abandoned by Aniruddha Singh Gautam (<email address hidden>) on branch: master
Review: https://review.openstack.org/148203
Reason: changes are submitted in patch#144630

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/144630
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=1f337c761bf73df050e435214935c498a2b3d028
Submitter: Jenkins
Branch: master

commit 1f337c761bf73df050e435214935c498a2b3d028
Author: singhannie <email address hidden>
Date: Wed Dec 31 03:47:38 2014 -0800

    Configures RADVD to send managed flag in RA
    for DHCP_STATEFUL

    RADVD process is configured so that it sends
    managed flag in RA for the subnets with
    ra_mode set to DHCP_STATEFUL. UT case is
    updated to check the presence of managed
    flag in config file of RADVD for
    DHCP_STATEFUL.

    Change-Id: If685846c0c0f67bf4c40f4f268b9d03bfa2b1654
    Closes-Bug: #1377843

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/juno
Review: https://review.openstack.org/152841

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/152841
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=3f73028a1ed7793d2a53cdc5dce365cab78f9634
Submitter: Jenkins
Branch: stable/juno

commit 3f73028a1ed7793d2a53cdc5dce365cab78f9634
Author: singhannie <email address hidden>
Date: Wed Dec 31 03:47:38 2014 -0800

    Configures RADVD to send managed flag in RA
    for DHCP_STATEFUL

    RADVD process is configured so that it sends
    managed flag in RA for the subnets with
    ra_mode set to DHCP_STATEFUL. UT case is
    updated to check the presence of managed
    flag in config file of RADVD for
    DHCP_STATEFUL.

    Change-Id: If685846c0c0f67bf4c40f4f268b9d03bfa2b1654
    Closes-Bug: #1377843
    (cherry picked from commit 1f337c761bf73df050e435214935c498a2b3d028)