Bug 1869771

Summary:	[RHOSP-15] Octavia-amphora: nf_conntrack: table full, dropping packet thrown during load test
Product:	Red Hat OpenStack	Reporter:	Shravan Kumar Tiwari <shtiwari>
Component:	openstack-octavia	Assignee:	Gregory Thiemonge <gthiemon>
Status:	CLOSED ERRATA	QA Contact:	Bruna Bonguardo <bbonguar>
Severity:	medium	Docs Contact:
Priority:	medium
Version:	15.0 (Stein)	CC:	bxfree, gthiemon, ihrachys, lpeer, majopela, michjohn, scohen
Target Milestone:	beta	Keywords:	Triaged
Target Release:	16.2 (Train on RHEL 8.4)
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	openstack-octavia-5.1.1-2.20210301165002.adce3dc.el8ost	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-09-15 07:08:45 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:
Embargoed:

Description Shravan Kumar Tiwari 2020-08-18 15:43:00 UTC

Description of problem:

During a performance test over an Octavia loadbalancer customer encountered nf_conntrack table full errors. which resulted in errors in the requests.

[root@amphora-a0ce9751-247d-48ab-9b13-53c6162beba1 ~]# dmesg -T
[Mon Aug 17 06:16:28 2020] nf_conntrack: table full, dropping packet
[Mon Aug 17 06:16:28 2020] nf_conntrack: table full, dropping packet


Version-Release number of selected component (if applicable):
- RHOSP15
- Customer using octavia-amphora-image provided by RedHat CDN and not any customized image

- [cloud-user@amphora-d1351773-8d87-46ef-aeca-146c2460c159 ~]$ rpm -qa | grep octavia
openstack-octavia-amphora-agent-3.1.0-3.el7ost.noarch
openstack-octavia-common-3.1.0-3.el7ost.noarch
python-octavia-3.1.0-3.el7ost.noarch


- [root@srv-zmb15-12 (PRD-ZM) ~]# rpm -qa | grep octavia
openstack-octavia-common-4.1.2-0.20200114080449.5a71643.el8ost.noarch
python3-octavia-lib-1.1.1-0.20190312101220.6b55d62.el8ost.noarch
python3-octavia-4.1.2-0.20200114080449.5a71643.el8ost.noarch
openstack-octavia-health-manager-4.1.2-0.20200114080449.5a71643.el8ost.noarch
openstack-octavia-worker-4.1.2-0.20200114080449.5a71643.el8ost.noarch
openstack-octavia-housekeeping-4.1.2-0.20200114080449.5a71643.el8ost.noarch


How reproducible:


Steps to Reproduce:
1.
2.
3.

Actual results:
getting nf_conntrack: table full, dropping packet error.

Expected results:
should not get 'dropping packet error ' as nf_contrack_bucket in amphora namespace should have the increased value loaded from the sysctl.d conf file.

Additional info:

-- Customer has opened an storyboard with more details: https://storyboard.openstack.org/#!/story/2008028

The sysctl file to increase nf_conntrack_buckets is set:

[root@amphora-a0ce9751-247d-48ab-9b13-53c6162beba1 ~]# cat /etc/sysctl.d/net.netfilter.nf_conntrack_buckets.conf
# This file was created by diskimage-builder.
net.netfilter.nf_conntrack_buckets = 125000

But when checked the apmhora-netns we can see that setting is ignored:

[root@amphora-a0ce9751-247d-48ab-9b13-53c6162beba1 ~]# ip net exec amphora-haproxy cat /proc/sys/net/netfilter/nf_conntrack_buckets
8192
[root@amphora-a0ce9751-247d-48ab-9b13-53c6162beba1 ~]# cat /proc/sys/net/netfilter/nf_conntrack_buckets
8192

Note: The current error disappeared when the RAM of amphora instances were increased then customer could see the increased bucket size in amphora namespace. but it has to be cal

Comment 1 Brian Haley 2020-08-19 14:39:01 UTC

Lowered priority because workaround identified in customer case.

Comment 5 Anton 2020-12-02 12:09:36 UTC

I have the same issue when the file '/etc/sysctl.d/net.netfilter.nf_conntrack_buckets.conf' exists with 125000 value inside, but after amphora VM boot this setting is not applied.

In journalctl I can see:
Dec 02 11:11:08 ubuntu systemd-sysctl[253]: Couldn't write '125000' to 'net/netfilter/nf_conntrack_buckets', ignoring: No such file or directory

It seems the issue in how sysctl settings are applied and depends on if nf_conntrack module is loaded or not.

Comment 6 Gregory Thiemonge 2020-12-02 12:29:05 UTC

(In reply to Anton from comment #5)
> I have the same issue when the file
> '/etc/sysctl.d/net.netfilter.nf_conntrack_buckets.conf' exists with 125000
> value inside, but after amphora VM boot this setting is not applied.
> 
> In journalctl I can see:
> Dec 02 11:11:08 ubuntu systemd-sysctl[253]: Couldn't write '125000' to
> 'net/netfilter/nf_conntrack_buckets', ignoring: No such file or directory
> 
> It seems the issue in how sysctl settings are applied and depends on if
> nf_conntrack module is loaded or not.

I proposed https://review.opendev.org/c/openstack/octavia/+/748749/ it should fix the issue but it's still in review

Comment 16 errata-xmlrpc 2021-09-15 07:08:45 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 (Red Hat OpenStack Platform (RHOSP) 16.2 enhancement 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.

https://access.redhat.com/errata/RHEA-2021:3483