Today, I noticed some errors in our SSL cert renewal log files, mostly related to domains where the IP address had changed. Concerned about this, rebuilt out SSL cert, which normally goes well without a hiccup.
However, for today, for some reason which I cannot explain, there was a PHP error after doing this update to our SSL cert:
[Mon Nov 19 02:11:44.903383 2018] [:error] [pid 13227] [client 218.30.103.113:24037] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:45.005312 2018] [:error] [pid 13205] [client 157.55.39.62:7669] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:45.169738 2018] [:error] [pid 13193] [client 157.55.39.62:7645] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:45.439660 2018] [:error] [pid 13199] [client 157.55.39.62:7687] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:45.607952 2018] [:error] [pid 13230] [client 157.55.39.62:7711] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:45.827490 2018] [:error] [pid 13182] [client 157.55.39.62:7704] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:45.988295 2018] [:error] [pid 13222] [client 157.55.39.62:7700] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:46.156724 2018] [:error] [pid 13210] [client 157.55.39.62:7741] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:46.323108 2018] [:error] [pid 13200] [client 157.55.39.62:7801] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:46.487172 2018] [:error] [pid 13203] [client 157.55.39.62:7779] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:46.654968 2018] [:error] [pid 13204] [client 157.55.39.62:7760] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:46.819326 2018] [:error] [pid 13214] [client 157.55.39.62:7790] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
[Mon Nov 19 02:11:46.984656 2018] [:error] [pid 13211] [client 157.55.39.62:7793] PHP Fatal error: xc_fcntl_mutex failed errno:9 in Unknown on line 0
I was able to quickly rebuild the SSL cert again, restart our web server, and all was fine; except in one of my browsers, I had to close and reopen the browser to clear the issue.
There was a total of a few seconds downtime because of the PHP error above, but all is find now. Normally, renewing SSL certs do not cause the kinds of PHP errors, but it did and we had a few seconds of downtime today because of that.