Bug 49771 - After graceful restart using mod_proxy_ajp, couldn't speak AJP to Tomcat until a full restart of httpd
Summary: After graceful restart using mod_proxy_ajp, couldn't speak AJP to Tomcat unti...
Status: RESOLVED LATER
Alias: None
Product: Apache httpd-2
Classification: Unclassified
Component: mod_proxy_ajp (show other bugs)
Version: 2.2.3
Hardware: PC Linux
: P2 normal (vote)
Target Milestone: ---
Assignee: Apache HTTPD Bugs Mailing List
URL:
Keywords: MassUpdate
Depends on:
Blocks:
 
Reported: 2010-08-17 19:01 UTC by Martin
Modified: 2018-11-07 21:10 UTC (History)
0 users



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Description Martin 2010-08-17 19:01:31 UTC
After a graceful restart of our RHEL 5.5's Apache 2.2
(httpd-2.2.3-43.el5.x86_64), all four of our webservers complained that:

[Tue Aug 17 08:48:54 2010] [notice] Graceful restart requested, doing restart
[Tue Aug 17 09:28:41 2010] [error] (111)Connection refused: proxy: AJP: attempt
to connect to 128.227.74.27:8000 (sakaiapp-prod06.osg.ufl.edu) failed
[Tue Aug 17 09:28:41 2010] [error] ap_proxy_connect_backend disabling worker
for (sakaiapp-prod06.osg.ufl.edu)
[Tue Aug 17 09:28:41 2010] [error] proxy: AJP: failed to make connection to
backend: sakaiapp-prod06.osg.ufl.edu
[Tue Aug 17 09:28:41 2010] [error] proxy: BALANCER:
(balancer://elearning2.courses.ufl.edu). All workers are in error state for
route (sakaiapp-prod05.osg.ufl.edu)
[Tue Aug 17 09:32:00 2010] [error] (111)Connection refused: proxy: AJP: attempt
to connect to 128.227.74.13:8000 (sakaiapp-prod04.osg.ufl.edu) failed
[Tue Aug 17 09:32:00 2010] [error] ap_proxy_connect_backend disabling worker
for (sakaiapp-prod04.osg.ufl.edu)
[Tue Aug 17 09:32:00 2010] [error] proxy: AJP: failed to make connection to
backend: sakaiapp-prod04.osg.ufl.edu
[Tue Aug 17 09:32:00 2010] [error] proxy: BALANCER:
(balancer://elearning2.courses.ufl.edu). All workers are in error state for
route (sakaiapp-prod03.osg.ufl.edu)


In the Tomcat 5.5.30 logs, we saw hundreds of:
2010-08-17 09:00:34.601 [ERROR] org.apache.coyote.ajp.AjpMessage:239 - Cannot
append null value
java.lang.NullPointerException
        at org.apache.coyote.ajp.AjpMessage.appendString(AjpMessage.java:239)
        at org.apache.coyote.ajp.AjpMessage.appendBytes(AjpMessage.java:175)
        at
org.apache.coyote.ajp.AjpAprProcessor.prepareResponse(AjpAprProcessor.java:1005)
        at
org.apache.coyote.ajp.AjpAprProcessor.action(AjpAprProcessor.java:510)
        at org.apache.coyote.Response.action(Response.java:183)
        at org.apache.coyote.Response.sendHeaders(Response.java:379)
        at
org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:313)
        at
org.apache.catalina.connector.OutputBuffer.close(OutputBuffer.java:280)
        at
org.apache.catalina.connector.Response.finishResponse(Response.java:484)
        at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:177)
        at
org.apache.coyote.ajp.AjpAprProcessor.process(AjpAprProcessor.java:444)
        at
org.apache.coyote.ajp.AjpAprProtocol$AjpConnectionHandler.process(AjpAprProtocol.java:472)
        at
org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1293)
        at java.lang.Thread.run(Thread.java:619)

All I can figure is that this a bug in the AJP connector on the Tomcat side,
though doing a 'real' (i.e. not graceful) restart of Apache httpd fixed the
issue. I'm submitting the issue to the Apache side as well, though, since a full restart fixed it.

The only change during the graceful was editing the balancer members of an unused vhost.
Comment 1 William A. Rowe Jr. 2018-11-07 21:10:03 UTC
Please help us to refine our list of open and current defects; this is a mass update of old and inactive Bugzilla reports which reflect user error, already resolved defects, and still-existing defects in httpd.

As repeatedly announced, the Apache HTTP Server Project has discontinued all development and patch review of the 2.2.x series of releases. The final release 2.2.34 was published in July 2017, and no further evaluation of bug reports or security risks will be considered or published for 2.2.x releases. All reports older than 2.4.x have been updated to status RESOLVED/LATER; no further action is expected unless the report still applies to a current version of httpd.

If your report represented a question or confusion about how to use an httpd feature, an unexpected server behavior, problems building or installing httpd, or working with an external component (a third party module, browser etc.) we ask you to start by bringing your question to the User Support and Discussion mailing list, see [https://httpd.apache.org/lists.html#http-users] for details. Include a link to this Bugzilla report for completeness with your question.

If your report was clearly a defect in httpd or a feature request, we ask that you retest using a modern httpd release (2.4.33 or later) released in the past year. If it can be reproduced, please reopen this bug and change the Version field above to the httpd version you have reconfirmed with.

Your help in identifying defects or enhancements still applicable to the current httpd server software release is greatly appreciated.