reload apache2 with mpm_event cause scoreboard is full

Bug #1466926 reported by Branislav Staron on 2015-06-19
70
This bug affects 13 people
Affects Status Importance Assigned to Milestone
apache2 (Ubuntu)
Medium
Unassigned
Trusty
Undecided
Unassigned
Xenial
Undecided
Unassigned
Zesty
Undecided
Unassigned

Bug Description

On the clean install Ubuntu 14.04 with Apache without almost any client load the Apache server with the command "service apache2 reload" itself allocates slots marked with "Gracefully finishing" for which rejects new connections.

For full rejection of new requests is sufficient to perform 4x command "service apache2 reload".

Ubuntu 14.04.2 LTS
Apache 2.4.7-ubuntu4.4 (mpm_event)
Kernel 2.16.0-30-generic

Reproduce problem:
#################################################
1/ service apache2 start
______________________________________________________W_________
___________.....................................................
......................

2/ service apache2 reload

.........................GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
GGGGGGGGGGG__________________________________________________W__
______________________

3/ service apache2 reload

___W_____________________GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
GGGGGGGGGGG__________________________________________________...
......................

4/ service apache2 reload

GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG___
W_____________________

5/ service apache2 reload -> Server Apache not responding
With logs in apache error log file:
... [mpm_event:error] [pid 9381:tid 1234563234] AH00485: scoreboard is full, not at MaxRequestWorkers
...
#################################################

My workaround was change to MPM module from "mpm_event" to "mpm_worker".

affects: installation-report (Ubuntu) → apache2 (Ubuntu)
Henti Smith (henti) wrote :

This bug has been discussed on the apache bug tracker :

https://bz.apache.org/bugzilla/show_bug.cgi?id=53555

There seems to be no movement to fix this that I can see. there is a patch which seems to fix it for users up to a higher usage level.

https://bz.apache.org/bugzilla/attachment.cgi?id=33158

Launchpad Janitor (janitor) wrote :

Status changed to 'Confirmed' because the bug affects multiple users.

Changed in apache2 (Ubuntu):
status: New → Confirmed
Stewart Campbell (sc-pulsion) wrote :

A patch has now been committed to trunk for this bug:
https://bz.apache.org/bugzilla/show_bug.cgi?id=53555#c65

ChristianEhrhardt (paelzer) wrote :

Thanks Steward to ping with the issue upstream now being resolved and a patch available!

Changed in apache2 (Ubuntu):
status: Confirmed → Triaged
importance: Undecided → Medium
Robie Basak (racb) on 2016-12-12
tags: added: server-next
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package apache2 - 2.4.25-3ubuntu2

---------------
apache2 (2.4.25-3ubuntu2) zesty; urgency=medium

  * Undrop (LP 1658469):
    - Don't build experimental http2 module for LTS:
      + debian/control: removed libnghttp2-dev Build-Depends (in universe).
      + debian/config-dir/mods-available/http2.load: removed.
      + debian/rules: removed proxy_http2 from configure.
      + debian/apache2.maintscript: remove http2 conffile.

 -- Nishanth Aravamudan <email address hidden> Fri, 10 Feb 2017 08:53:43 -0800

Changed in apache2 (Ubuntu):
status: Triaged → Fix Released
Nick (n6ck) wrote :

Will this be backported to Trusty or Xenial?

Yes this is impacting on Xenial - when will this be backported to currently supported LTS releases?

Haw Loeung (hloeung) on 2017-07-10
Changed in apache2 (Ubuntu Xenial):
status: New → Confirmed
Changed in apache2 (Ubuntu Trusty):
status: New → Confirmed
Haw Loeung (hloeung) on 2017-07-10
Changed in apache2 (Ubuntu Zesty):
status: New → Fix Released
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