Bug 1266977

Summary: ipset - Hash is full, cannot add more elements
Product: Red Hat OpenStack Reporter: Benjamin Schmaus <bschmaus>
Component: openstack-neutronAssignee: Miguel Angel Ajo <mangelajo>
Status: CLOSED ERRATA QA Contact: Itzik Brown <itbrown>
Severity: urgent Docs Contact:
Priority: urgent    
Version: 6.0 (Juno)CC: amuller, chrisw, dmaley, ihrachys, jschluet, majopela, nyechiel, rhos-flags, tfreger, yeylon
Target Milestone: asyncKeywords: Triaged, ZStream
Target Release: 6.0 (Juno)   
Hardware: x86_64   
OS: Linux   
Fixed In Version: openstack-neutron-2014.2.3-16.el7ost Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-10-15 16:10:20 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description Benjamin Schmaus 2015-09-28 17:30:10 UTC
Description of problem:

We have instances failing to boot because users are putting very large
subnets (e.g., /15) into allowed_address_pairs in Neutron.  It appears
that we're hitting some sort of 64K limit in the ipset implementation.

The users putting subnets into allowed_address_pairs, so it seems that
they should be stored in ipset as a subnet as well, not individual

This results in errors like from an instance booting:
2015-09-25 17:17:21.418 51840 INFO heat.engine.stack [-] Stack CREATE
FAILED (VMG-NEC2-OAMA-24ilgto3rllb): Resource CREATE failed: Error:
Server VMG-NEC2-OAM-A delete failed: (500) Build of instance
6031be29-f194-43fb-b05b-92e0c2d7cd18 aborted: Failed to allocate the
network(s), not rescheduling.

On the compute host, the neutron logs contain items like:
2015-09-25 12:04:13.129 58378 ERROR neutron.agent.linux.utils
[req-c8c2e2e2-1cc5-4fab-b1b6-b84f78043459 None]
Command: ['sudo', 'neutron-rootwrap', '/etc/neutron/rootwrap.conf',
'ipset', 'add', '-exist', 'IPv4c3742bfb-7f15-4c92-b', '']
Exit code: 1
Stdout: ''
Stderr: 'ipset v6.19: Hash is full, cannot add more elements\n'

We can see that the ipset hash is indeed near a 64K limit, if that is
[root@host nova]# ipset list | wc -l

We can see that the sets have a limit of 65536:
Name: IPv6f60f0540-fa6c-4a8d-9
Type: hash:ip
Revision: 1
Header: family inet6 hashsize 1024 maxelem 65536

Version-Release number of selected component (if applicable): OSP6

How reproducible:
100% in larger deployments

Steps to Reproduce:

Actual results:

Expected results:

Additional info:

Upstream bug: https://bugs.launchpad.net/neutron/+bug/1439817

Upstream code commit for OSP6: https://git.openstack.org/cgit/openstack/neutron/commit/?id=0325b98c54af276064e367db603bfeb525bbb790

Comment 12 Benjamin Schmaus 2015-10-09 15:21:03 UTC
Hotfix worked for my client where it was applied.

Comment 16 Itzik Brown 2015-10-15 11:06:20 UTC
Checked with openstack-neutron-2014.2.3-19.el7ost.noarch

Comment 18 errata-xmlrpc 2015-10-15 16:10:20 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.