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Bug 2119769

Summary: nf_conntrack_max low in Amphora VMs with low memory
Product: Red Hat OpenStack Reporter: François Rigault <frigo>
Component: openstack-octaviaAssignee: Tom Weininger <tweining>
Status: CLOSED ERRATA QA Contact: Bruna Bonguardo <bbonguar>
Severity: medium Docs Contact:
Priority: medium    
Version: 16.2 (Train)CC: erpeters, gthiemon, lpeer, majopela, scohen, tweining
Target Milestone: z4Keywords: Triaged
Target Release: 16.2 (Train on RHEL 8.4)   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: openstack-octavia-5.1.3-2.20220715135807.f18a230.el8ost Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2022-12-07 19:24:09 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 François Rigault 2022-08-19 11:10:46 UTC 
Description of problem:
amphora-netns.service increases nf_conntrack_buckets but fails to increase the max number of conntracks
This can cause connections drops  (kernel: nf_conntrack: table full, dropping packet).
This problem was described in https://storyboard.openstack.org/#!/story/2008028
but the solution does not seem to work

Version-Release number of selected component (if applicable):
RHOSP 16.2.3
openstack-octavia-common-5.1.3-2.20220328185156.el8ost.noarch (in the amphora VM)

How reproducible:
all the time

Steps to Reproduce:
1. create an amphora VM with 1GB memory or 2GB memory
2. ssh into it
3. ip netns exec amphora-haproxy sysctl net.netfilter.nf_conntrack_max

Actual results:
32768 for 1GB RAM VM
65536 for 2GB RAM VM


Expected results:
125440x4


Additional info:
from https://storyboard.openstack.org/#!/story/2008028:
for 1GB RAM VM, nf_conntrack_buckets defaults to 8192, and nf_conntrack_max defaults to 8192x4

the change introduced in the story change nf_conntrack_buckets to 125440 but the nf_conntrack_max is left unchanged, possibly leading to conntrack exhaustion.
Comment 3 Gregory Thiemonge 2022-09-01 08:06:23 UTC 
For 16.1, another BZ includes the bugfix: https://bugzilla.redhat.com/show_bug.cgi?id=2123225
Comment 14 errata-xmlrpc 2022-12-07 19:24:09 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 (Release of components for Red Hat OpenStack Platform 16.2.4), 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/RHBA-2022:8794