Bug 1302401

Summary: backport the metadata_cache_expiration config option to avoid harcoded value of 15s
Product: Red Hat OpenStack Reporter: Eoghan Glynn <eglynn>
Component: openstack-novaAssignee: Sven Anderson <svanders>
Status: CLOSED ERRATA QA Contact: Prasanth Anbalagan <panbalag>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 5.0 (RHEL 7)CC: berrange, dasmith, dcadzow, eglynn, kchamart, ndipanov, panbalag, sbauza, sferdjao, sgordon, vromanso, yeylon
Target Milestone: ---Keywords: FeatureBackport, FutureFeature, ZStream
Target Release: 5.0 (RHEL 7)   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: openstack-nova-2014.1.5-23.el7ost Doc Type: Enhancement
Doc Text:
Feature: Allow users to set metadata_cache_expiration. Reason: This config option should be backported to OSP5 in order to provide the same flexibility and avoid premature cache expiration in cases where the metadata is highly static. Result: Users may configure the metadata_cache_expiration in nova.conf
 Story Points: ---
Clone Of:
: 1302811 1302812 1302813 (view as bug list) Environment:
Last Closed: 2016-03-08 17:08:39 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:
Bug Depends On:    
Bug Blocks: 1302811, 1302812, 1302813    
Attachments:
Description Flags
Nova startup logs (tar) none

Description Eoghan Glynn 2016-01-27 18:30:17 UTC 
The metadata cache expiration timeout was hardcoded to 15 seconds in versions older than kilo (OSP7).

In kilo a new configuration option was added:

  'metadata_cache_expiration',

  Time in seconds to cache metadata; 0 to disable
  metadata caching entirely (not recommended). Increasing
  this should improve response times of the metadata API
  when under heavy load. Higher values may increase memory
  usage and result in longer times for host metadata
  changes to take effect.

introduced in:

  https://review.openstack.org/159264

This config option should be backported to OSP5 in order to provide the same flexibility and avoid premature cache expiration in cases where the metadata is highly static.
Comment 4 Prasanth Anbalagan 2016-03-01 14:53:46 UTC 
Verified as follows - No error observed during nova startup with the option metadata_cache_expiration defined in /etc/nova/nova.conf.

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Version
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[root@rhos-compute-node-02 ~(keystone_admin)]# yum list installed | grep openstack-nova
openstack-nova-api.noarch        2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle
openstack-nova-cert.noarch       2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle
openstack-nova-common.noarch     2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle
openstack-nova-compute.noarch    2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle
openstack-nova-conductor.noarch  2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle
openstack-nova-console.noarch    2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle
openstack-nova-novncproxy.noarch 2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle
openstack-nova-scheduler.noarch  2014.1.5-27.el7ost      @rhelosp-5.0-el7-puddle

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Logs
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[root@rhos-compute-node-02 ~(keystone_admin)]# 
[root@rhos-compute-node-02 ~(keystone_admin)]# 

[root@rhos-compute-node-02 ~(keystone_admin)]# 
[root@rhos-compute-node-02 ~(keystone_admin)]# grep "metadata_cache" /etc/nova/nova.conf 
metadata_cache_expiration = 15
[root@rhos-compute-node-02 ~(keystone_admin)]# 

P.S: Nova startup logs has been attached as a tar file
Comment 5 Prasanth Anbalagan 2016-03-01 14:54:36 UTC 
Created attachment 1131962 [details]
Nova startup logs (tar)
Comment 7 errata-xmlrpc 2016-03-08 17:08:39 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.

https://rhn.redhat.com/errata/RHBA-2016-0361.html