yahoo-eng-team team mailing list archive

Thread
Date
[Bug 1818566] [NEW] If ipv6 is disabled through the kernel, neutron-dhcp-agent fails to create the tap devices due to error regarding ipv6

To: yahoo-eng-team@xxxxxxxxxxxxxxxxxxx
From: David Hill <1818566@xxxxxxxxxxxxxxxxxx>
Date: Mon, 04 Mar 2019 20:30:00 -0000
Reply-to: Bug 1818566 <1818566@xxxxxxxxxxxxxxxxxx>
Sender: bounces@xxxxxxxxxxxxx
*** This bug is a duplicate of bug 1618878 ***
    https://bugs.launchpad.net/bugs/1618878

Public bug reported:

If we disable ipv6 using ipv6.disable=1 at the kernel runtime, neutron-
dhcp-agent stops creating the tap devices and fails here:


dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.linux.utils [-] Exit code: 255; Stdin: ; Stdout: ; Stderr: sysctl: cannot stat /proc/sys/net/ipv6/conf/default/accept_ra: No such file or directory
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent [-] Unable to enable dhcp for 310b9752-06a5-4d7b-98ae-1ba8536e22fa.
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent Traceback (most recent call last):
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/dhcp/agent.py", line 140, in call_driver
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     getattr(driver, action)(**action_kwargs)
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/dhcp.py", line 213, in enable
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     interface_name = self.device_manager.setup(self.network)
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/dhcp.py", line 1441, in setup
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     n_const.ACCEPT_RA_DISABLED)
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/interface.py", line 260, in configure_ipv6_ra
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     'value': value}])
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/ip_lib.py", line 912, in execute
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     log_fail_as_error=log_fail_as_error, **kwargs)
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py", line 148, in execute
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     raise ProcessExecutionError(msg, returncode=returncode)
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent ProcessExecutionError: Exit code: 255; Stdin: ; Stdout: ; Stderr: sysctl: cannot stat /proc/sys/net/ipv6/conf/default/accept_ra: No such file or directory
dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent

** Affects: neutron
     Importance: Undecided
         Status: New

** Description changed:

- I see the same behavior here though by setting that in
- /boot/grub/grub.cfg and rebooting.  I lost all my taps.  Investigating.
+ If we disable ipv6 using ipv6.disable=1 at the kernel runtime, neutron-
+ dhcp-agent stops creating the tap devices and fails here:
  
- BTW, I'm not sure totally disabling ipv6 from the kernel is the best
- method to disable ipv6 ... In this KCS[ [1] , we notify the customers
- that this might break SSH XFowarding.   In this case, the taps are no
- longer created but according to this KCS [2], it should still be created
- with ipv4 links.  That could be a bug.  Perhaps open a BZ for this
- issue.
- 
- It looks like the problem is here:
  
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.linux.utils [-] Exit code: 255; Stdin: ; Stdout: ; Stderr: sysctl: cannot stat /proc/sys/net/ipv6/conf/default/accept_ra: No such file or directory
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent [-] Unable to enable dhcp for 310b9752-06a5-4d7b-98ae-1ba8536e22fa.
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent Traceback (most recent call last):
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/dhcp/agent.py", line 140, in call_driver
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     getattr(driver, action)(**action_kwargs)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/dhcp.py", line 213, in enable
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     interface_name = self.device_manager.setup(self.network)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/dhcp.py", line 1441, in setup
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     n_const.ACCEPT_RA_DISABLED)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/interface.py", line 260, in configure_ipv6_ra
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     'value': value}])
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/ip_lib.py", line 912, in execute
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     log_fail_as_error=log_fail_as_error, **kwargs)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py", line 148, in execute
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     raise ProcessExecutionError(msg, returncode=returncode)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent ProcessExecutionError: Exit code: 255; Stdin: ; Stdout: ; Stderr: sysctl: cannot stat /proc/sys/net/ipv6/conf/default/accept_ra: No such file or directory
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent

-- 
You received this bug notification because you are a member of Yahoo!
Engineering Team, which is subscribed to neutron.
https://bugs.launchpad.net/bugs/1818566

Title:
  If ipv6 is disabled through the kernel, neutron-dhcp-agent fails to
  create the tap devices due to error regarding ipv6

Status in neutron:
  New

Bug description:
  If we disable ipv6 using ipv6.disable=1 at the kernel runtime,
  neutron-dhcp-agent stops creating the tap devices and fails here:

  
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.linux.utils [-] Exit code: 255; Stdin: ; Stdout: ; Stderr: sysctl: cannot stat /proc/sys/net/ipv6/conf/default/accept_ra: No such file or directory
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent [-] Unable to enable dhcp for 310b9752-06a5-4d7b-98ae-1ba8536e22fa.
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent Traceback (most recent call last):
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/dhcp/agent.py", line 140, in call_driver
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     getattr(driver, action)(**action_kwargs)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/dhcp.py", line 213, in enable
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     interface_name = self.device_manager.setup(self.network)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/dhcp.py", line 1441, in setup
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     n_const.ACCEPT_RA_DISABLED)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/interface.py", line 260, in configure_ipv6_ra
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     'value': value}])
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/ip_lib.py", line 912, in execute
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     log_fail_as_error=log_fail_as_error, **kwargs)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent   File "/usr/lib/python2.7/site-packages/neutron/agent/linux/utils.py", line 148, in execute
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent     raise ProcessExecutionError(msg, returncode=returncode)
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent ProcessExecutionError: Exit code: 255; Stdin: ; Stdout: ; Stderr: sysctl: cannot stat /proc/sys/net/ipv6/conf/default/accept_ra: No such file or directory
  dhcp-agent.log:2019-03-04 19:29:13.342 5869 ERROR neutron.agent.dhcp.agent

To manage notifications about this bug go to:
https://bugs.launchpad.net/neutron/+bug/1818566/+subscriptions
Follow ups

[Bug 1818566] Re: If ipv6 is disabled through the kernel, neutron-dhcp-agent fails to create the tap devices due to error regarding ipv6
From: Brian Haley, 2019-03-04