Hello all, I'm struggling with understanding something in the error.log and could use some pointers on how to troubleshoot this. I've inherited a web app that uses apache as the webserver and is also using user apache user auth.
Occasionally, Apache will just restart itself and it seems to take a while (Figure 0). I've ruled out usual suspects like memory, disk or processing capacity (this Ubuntu instance is on an ec2 instance with some very good specs, and the resource graphs have never even been close to high). Server and version details are in Figure 2 below.
I'm trying to determine the root cause of this behavior. One culprit, based on some
Stack reading, was possibly a reload/restart of Apache anytime the logs rotate. I've read that it's supposed to be a graceful restart, but perhaps something is causing the reload in the logrotate file to be ungraceful.
I started grokking the error logs more carefully and spotted some error messages (Figure 1). I'm not sure what these mean, and their timestamps don't necessarily perfectly correlate to the restart / bad user experience (unresponsive web app).
Does anyone here have any suggestions on where I can learn some more about the errors in Figure 1, or perhaps on additional log or config files I could be examining ?
Figure 0 - Restart ? (error.log)
[Wed Jan 12 00:00:08.735348 2022] [mpm_event:notice] [pid 14569:tid 139723494018368] AH00489: Apache/2.4.52 (Ubuntu) OpenSSL/1.1.1f configured -- resuming normal operations
Figure 1 - Error Entry (error.log)
[Wed Jan 12 09:28:57.459259 2022] [session:error] [pid 25478:tid 139722760365824] (20014)Internal error (specific information not available): [client 172.70.230.157:44264] AH01816: error while loading the session, session not loaded: /socket.io/
[Wed Jan 12 09:28:57.459224 2022] [session_dbd:error] [pid 25478:tid 139722760365824] [client 172.70.230.157:44264] AH01854: query execution error saving session 'd2866875-f3d3-475b-a523-aa34e2ee5351' in database using query 'selectsession':
Figure 2 - Server/Apache Details (apache2 -v)
Server version: Apache/2.4.52 (Ubuntu)
Server built: 2021-12-28T20:18:12
Ubuntu version: 18.04 LTS
