Red Hat Bugzilla – Bug 143724
mysqld init needs to specify the mysqld.pid location on startup
Last modified: 2013-07-02 23:03:06 EDT
Description of problem: The /etc/init.d/mysqld script "start" function needs to specify a mysqld.pid location to safe_mysqld so that it matches the mysqld.pid location checked later by "stop". The symptom of the problem is that "service mysqld stop" fails and the mysqld server is not stopped -- tracing this reveals that safe_mysqld doesn't write the PID where the stop function expects it. Version-Release number of selected component (if applicable): mysqld-server-3.23.58-13 How reproducible: Very Steps to Reproduce: 1. service mysqld start 2. ls /var/run/mysqld Actual results: Nothing Expected results: mysqld.pid Additional info: Fixable by adding "--pid-file=/var/run/mysqld/mysqld.pid" to the call to safe_mysqld.
Created attachment 109123 [details] patch to add pid-file argument to mysqld init script
There is already an entry pid-file=/var/run/mysqld/mysqld.pid in the standard /etc/my.cnf. I don't see a need to repeat it in the init file.
Hmm. That explains it. I had a my.cnf file that was working perfectly well when I upgraded and didn't realize that line needed to be added. I checked the /etc/sysconfig/mysqld and didn't see it. I also didn't see a "pid-file" line when I checked the sample configuration files in /usr/share/docs/mysql-server-3.23.58/. Nor was there a README.REDHAT file. If you don't want to move the pid-file setting from the my.cnf file to the init file or sysconfig file, could I suggest at least adding a README.REDHAT file to the docs directory to alert sysadmins that this line is necessary to work with the Redhat/Fedora init file, as is differs from the mysql defaults? Alternatively, a one-line comment in the init file that the pid is set in my.cnf (as opposed to /etc/sysconfig/mysqld or anywhere else) would be helpful and user-friendly.
Er ... upgraded from what exactly? I haven't been maintaining Red Hat's mysql RPMs for very long, but AFAICT from our CVS we have always had the pid-file line in there. The Red Hat build differs from MySQL AB's out-of-the-box configuration in several ways (different directory paths mostly) so I'm not sure that it should be expected to overwrite a raw MySQL build without trouble.
The upgrade was to FC3 from FC2, but that was an upgrade from FC1, RH8 (I think), etc. It's hard to say where the config file changed on my end -- somewhere along the line I probably took the example files from /usr/share/docs/mysql-server-xx.xx.xx/ and customized it, and never noticed the pid issue until now. During upgrades there are a ton of .rpmsave and .rpmnew files that get created, diffing them all takes a lot of time and I may have just missed it. My broader point was that anywhere that a RedHat build differs substantially, having a README.REDHAT with the differences or at least a comment in the init script is a very user-friendly way of communicating the differences. The init script depends on the pid file being in a certain location, so my personal feeling is that that's the place (or the corresponding /etc/sysconfig/mysqld file) to put something like that. If you want to keep it in the my.cnf file, that's functionally the same, but I think it would make sense to note that fact in the init script in case anyone ever replaces the default my.cnf with something (like from the docs directory or of their own invention) that doesn't include the pid-file option.
Nice to read that there is already an entry for this 'problem'. I registered an account on Bugzilla especially for this issue. It took me 2,5 hours to find out why my 'service mysqld stop' [FAILED] all the time. The reason was that i replaced '/etc/my.cnf' with '/usr/share/doc/mysql-server-3.23.58/my-medium.cnf', hoping that would better suit my situation. And in that file the location for the .pid file was not defined. So mysql placed it in the /var/lib. I hope (for other people who will encounter this problem) that it will be changed to something more flexible.
Given that MySQL AB supplies sample config files that don't contain any pid-file entry, I suppose you're right that we'd best not assume there is one in the file. I've added a --pid-file switch to the init script in mysql-3.23.58-14 for FC3. This is still an open issue for RHEL4 though.
This is fixed in pending updates for RHEL-3 and RHEL-4.