Resolved Error 500 in the monitor logs

[tkalfaoglu]

In /var/log/messages I see:

Aug 27 10:24:43 jedi monit: GENERIC: receiving unexpected data [HTTP/1.0 500 Internal Server Error
Aug 27 10:24:43 jedi monit: ]
Aug 27 10:24:43 jedi monit: 'apache' failed protocol test [generic] at INET[127.0.0.1:7080].
Aug 27 10:24:43 jedi monit: 'apache' trying to restart
Aug 27 10:24:43 jedi monit: 'apache' stop: /usr/local/psa/admin/bin/websrvmng
Aug 27 10:24:43 jedi systemd: Stopping The Apache HTTP Server...
Aug 27 10:24:44 jedi monit: 'apache' start: /usr/local/psa/admin/bin/websrvmng
Aug 27 10:24:57 jedi systemd: Stopped The Apache HTTP Server.
Aug 27 10:24:57 jedi systemd: Starting The Apache HTTP Server...
Aug 27 10:24:59 jedi systemd: Started The Apache HTTP Server.

Any ideas how I can debug this?

 

[tkalfaoglu]

I followed the plesk documentation at Watchdog cannot monitor Apache or nginx: failed protocol test [generic]

but it still says

Aug 29 13:04:16 jedi systemd: Starting Watchdog monit...
Aug 29 13:04:16 jedi echo: Starting monit service (Watchdog)
Aug 29 13:04:16 jedi systemd: Started Watchdog monit.
Aug 29 13:04:16 jedi monit: Starting monit daemon with http interface at [127.0.0.1:2911]
Aug 29 13:04:16 jedi monit: Starting monit HTTP server at [127.0.0.1:2911]
Aug 29 13:04:16 jedi monit: monit HTTP server started
Aug 29 13:04:16 jedi monit: GENERIC: receiving unexpected data [HTTP/1.0 500 Internal Server Error
Aug 29 13:04:16 jedi monit: ]
Aug 29 13:04:16 jedi monit: 'apache' failed protocol test [generic] at INET[127.0.0.1:7080].
Aug 29 13:04:16 jedi monit: 'apache' trying to restart
Aug 29 13:04:16 jedi monit: 'apache' stop: /usr/local/psa/admin/bin/websrvmng
Aug 29 13:04:16 jedi systemd: Stopping The Apache HTTP Server...
Aug 29 13:04:17 jedi wdcollect: Connection to server has been established.
Aug 29 13:04:17 jedi wdcollect[9597]: Connection to server has been established.
Aug 29 13:04:17 jedi monit: 'apache' start: /usr/local/psa/admin/bin/websrvmng
Aug 29 13:04:21 jedi systemd: Stopped The Apache HTTP Server.
Aug 29 13:04:21 jedi systemd: Starting The Apache HTTP Server...
Aug 29 13:04:23 jedi systemd: Started The Apache HTTP Server.

 

[tkalfaoglu]

More clues:

# curl -I 95.216.38.116:80
HTTP/1.1 200 OK
Server: nginx
Date: Wed, 29 Aug 2018 10:09:24 GMT
Content-Type: text/html; charset=utf-8
Connection: keep-alive
Vary: Accept-Encoding
X-Powered-By: PHP/5.4.45
Cache-Control: max-age=3600
Expires: Wed, 29 Aug 2018 11:09:24 GMT
Vary: User-Agent

[root@jedi etc]# curl -I 95.216.38.116:7080
HTTP/1.0 500 Internal Server Error
Date: Wed, 29 Aug 2018 10:09:27 GMT
Server: Apache
X-Powered-By: PHP/5.4.45
Cache-Control: max-age=3600
Expires: Wed, 29 Aug 2018 11:09:27 GMT
Vary: User-Agent
Connection: close
Content-Type: text/html; charset=utf-8

 

[tkalfaoglu]

and the 127.0.0.1 branch:

[root@jedi etc]# curl -I 127.0.0.1:7080
HTTP/1.0 500 Internal Server Error
Date: Wed, 29 Aug 2018 10:11:47 GMT
Server: Apache
X-Powered-By: PHP/5.4.45
Cache-Control: max-age=3600
Expires: Wed, 29 Aug 2018 11:11:47 GMT
Vary: User-Agent
Connection: close
Content-Type: text/html; charset=utf-8

[root@jedi etc]# curl -I 127.0.0.1:80
curl: (7) Failed connect to 127.0.0.1:80; Connection refused

 

[tkalfaoglu]

I should just write these to a BLOG instead of writing them to this forum; since the plesk staff respond very late anyway.
With trial and error I found that the first IP of the machine and the port 80 are the only ones that respond with an OK 200.
Therefore I'm changing the monitrc file accordingly.