Bug 1266975 - ipset - Hash is full, cannot add more elements
ipset - Hash is full, cannot add more elements
Product: Red Hat OpenStack
Classification: Red Hat
Component: openstack-neutron (Show other bugs)
6.0 (Juno)
x86_64 Linux
unspecified Severity urgent
: ---
: 6.0 (Juno)
Assigned To: lpeer
Toni Freger
: Triaged, ZStream
: 1266974 (view as bug list)
Depends On:
  Show dependency treegraph
Reported: 2015-09-28 13:29 EDT by Benjamin Schmaus
Modified: 2016-04-26 14:52 EDT (History)
5 users (show)

See Also:
Fixed In Version: openstack-neutron-2014.2.3-16.el7ost
Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of:
Last Closed: 2016-02-08 09:17:44 EST
Type: Bug
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Benjamin Schmaus 2015-09-28 13:29:32 EDT
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 2 Jakub Libosvar 2015-10-07 09:58:49 EDT
*** Bug 1266974 has been marked as a duplicate of this bug. ***
Comment 5 Toni Freger 2016-01-21 04:08:18 EST
Have tested on osp6 with 2 compute nodes.

neutron subnet ( created without errors:
  allocation_pools  | {"start": "", "end": ""} |
| cidr              | 

30 instances booted, no errors on openwswitch log of both computes were found.
Comment 7 errata-xmlrpc 2016-02-08 09:17:44 EST
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.


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