Cron command causes the errors in proxy_error_log: connect() failed (111: Connection refused) while connecting to upstream

Symptoms

• The following errors can be observed in domain's nginx log file /var/www/vhosts/system/example.com/logs/proxy_error_log :

2017/04/30 01:10:44 [error] 1891#0: *659139 connect() failed (111: Connection refused) while connecting to upstream, client:  203.0.113.1, server: example.com, request: "HEAD /pro/obvita HTTP/1.1", upstream: "http:// 203.0.113.2:7080/subdir/", host: "example.com", referrer: "http://example.com/subdir"

• The following error can be found in Apache web server log for the same time:

[Sun Apr 30 01:10:02.593054 2017] [mpm_event:notice] [pid 93116:tid 140623768049536] AH00491: caught SIGTERM, shutting down

• The aforementioned errors occur at the same time when the command /etc/init.d/apache2 re start configured in cron is executed:

# crontab  -l
[..]
MAILTO=""
10      *      *      *      *      /etc/init.d/apache2 restart

Cause

Apache is temporarily not available due to restart caused by the cron scenario each hour.

Resolution

If this scheduled script was added in Plesk, then it can be removed in Tools & Settings > Scheduled Tasks .

Alternatively, edit cron tasks with the command:

# crontab -e