IPv6 addresses is not correctly configured

[Hengqing Hu]

In an IPv6 subnet which has ipv6_address_mode set slaac, Neutron use EUI-64 address assignment for all the addresses.

In this case, it would generate an exception while trying to adding to dhcp port.

[Boden R (boden)]

I've been trying to reproduce this one on a fresh devstack install, but am unable to.

I've simply been creating ipv6 subnets w/slaac and ensuring their DHCP port becomes active after creation. So far I haven't seen any issues.

Can you possibly provide additional details such as:
- Steps on how to reproduce, so I can try to see the error.
- The exception you are seeing.

Thanks

[Hengqing Hu (hudayou)]

Aug 17 14:56:47 server01 neutron-dhcp-agent[9649]: INFO neutron.agent.dhcp.agent [-] Synchronizing state
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: INFO neutron.agent.dhcp.agent [None req-04a25782-0f4c-4219-8e50-07c5e85cea73 None None] All active networks have been fetched through RPC.
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: INFO neutron.agent.dhcp.agent [-] Starting network ba1019d4-9b31-46d2-8f81-99693f1ed277 dhcp configuration
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: DEBUG neutron.agent.dhcp.agent [-] Calling driver for network: ba1019d4-9b31-46d2-8f81-99693f1ed277 action: enable {{(pid=9649) call_driver /opt/stack/neutron/neutron/agent/dhcp/agent.py:133}}
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ip', '-o', 'netns', 'list'] {{(pid=9649) execute_rootwrap_daemon /opt/stack/neutron/neutron/agent/linux/utils.py:108}}
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: DEBUG oslo_rootwrap.client [-] Popen for ['sudo', '/usr/local/bin/neutron-rootwrap-daemon', '/etc/neutron/rootwrap.conf'] command has been instantiated {{(pid=9649) _initialize /usr/local/lib/python2.7/dist-packages/oslo_rootwrap/client.py:68}}
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: INFO neutron.agent.dhcp.agent [-] Starting network bcf3c383-dc35-4ec3-87cc-db3ac5e5f681 dhcp configuration
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: DEBUG neutron.agent.dhcp.agent [-] Calling driver for network: bcf3c383-dc35-4ec3-87cc-db3ac5e5f681 action: enable {{(pid=9649) call_driver /opt/stack/neutron/neutron/agent/dhcp/agent.py:133}}
Aug 17 14:56:52 server01 neutron-dhcp-agent[9649]: DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ip', '-o', 'netns', 'list'] {{(pid=9649) execute_rootwrap_daemon /opt/stack/neutron/neutron/agent/linux/utils.py:108}}
Aug 17 14:56:52 server01 sudo[9708]: stack : TTY=unknown ; PWD=/ ; USER=root ; COMMAND=/usr/local/bin/neutron-rootwrap-daemon /etc/neutron/rootwrap.conf
Aug 17 14:56:52 server01 sudo[9708]: pam_unix(sudo:session): session opened for user root by (uid=0)
Aug 17 14:56:54 server01 neutron-dhcp-agent[9649]: INFO oslo_rootwrap.client [-] Spawned new rootwrap daemon process with pid=9708
Aug 17 14:56:54 server01 neutron-dhcp-agent[9649]: DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ip', 'netns', 'exec', 'qdhcp-ba1019d4-9b31-46d2-8f81-99693f1ed277', 'sysctl', '-w', 'net.ipv6.conf.default.accept_ra=0'] {{(pid=9649) execute_rootwrap_daemon /opt/stack/neutron/neutron/agent/linux/utils.py:108}}
Aug 17 14:56:54 server01 neutron-dhcp-agent[9649]: DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ip', 'netns', 'exec', 'qdhcp-bcf3c383-dc35-4ec3-87cc-db3ac5e5f681', 'sysctl', '-w', 'net.ipv6.conf.default.accept_ra=0'] {{(pid=9649) execute_rootwrap_daemon /opt/stack/neutron/neutron/agent/linux/utils.py:108}}
Aug 17 14:56:54 server01 neutron-dhcp-agent[9649]: DEBUG neutron.agent.linux.utils [-] Running command (rootwrap daemon): ['ip', 'netns', 'exec', 'qdhcp-ba1019d4-9b31-46d2-8f81-99693f1ed277', 'ip', 'link', 'set', 'ns-f455f818-70', 'up'] {{(pid=9649) execute_r...

[Hengqing Hu (hudayou)]

In order to reproduce the fault, you need to set ipv6 address mode to slacc and leave ipv6 ra mode to unset, also you need an external router simulator to produce the ipv6 address.
ipv6 ra mode ipv6 address mode radvd A,M,O External Router A,M,O Description
N/S slaac Off 1,0,0 Guest instance obtains IPv6 address from non-OpenStack router using SLAAC.

[Hengqing Hu (hudayou)]

Here is the reference page:
https://docs.openstack.org/ocata/networking-guide/config-ipv6.html

[Dr. Jens Harbott (j-harbott)]

This may be related to https://bugs.launchpad.net/neutron/+bug/1627902. Please show the exact version of Neutron you are using and the definition of your network and subnet.

[Hengqing Hu (hudayou)]

The fix is here:
https://review.openstack.org/#/c/491409/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/491409
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=6c437b7cedf8baf1dca857934ac438511d461141
Submitter: Zuul
Branch: master

commit 6c437b7cedf8baf1dca857934ac438511d461141
Author: Jacky Hu <email address hidden>
Date: Mon Aug 7 17:04:37 2017 +0800

    Correctly configure the IPv6 LLA address

    Handle a corner case where the address allocated by slaac is the
    same as the ipv6 default link local address.

    Closes-bug: #1709215
    Change-Id: Ida667292fce41e281e016d56a278eef3b8939ed4

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 12.0.0.0b2 development milestone.