503 service unavailable. Apache crashes once in 7-10 days - apache

Question

I use Apache server on Ubuntu 14.04. In order redirect all requests from mypage.com to mypage.com:8080/myapp I use mod_proxy. My 000-default.conf looks as follows:
<VirtualHost *:80>
# The ServerName directive sets the request scheme, hostname and port that
# the server uses to identify itself. This is used when creating
# redirection URLs. In the context of virtual hosts, the ServerName
# specifies what hostname must appear in the request's Host: header to
# match this virtual host. For the default virtual host (this file) this
# value is not decisive as it is used as a last resort host regardless.
# However, you must set it for any further virtual host explicitly.
#ServerName www.example.com
ServerAdmin webmaster#localhost
DocumentRoot /var/www/html
# Available loglevels: trace8, ..., trace1, debug, info, notice, warn,
# error, crit, alert, emerg.
# It is also possible to configure the loglevel for particular
# modules, e.g.
#LogLevel info ssl:warn
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
ProxyPass / http://mypage.com:8080/myapp/ retry=0 timeout=10
ProxyPassReverse / http://mypage.com:8080/myapp/
ServerName mypage.com
# For most configuration files from conf-available/, which are
# enabled or disabled at a global level, it is possible to
# include a line for only one particular virtual host. For example the
# following line enables the CGI configuration for this host only
# after it has been globally disabled with "a2disconf".
#Include conf-available/serve-cgi-bin.conf
</VirtualHost>
And that is my ports.conf
# If you just change the port or add more ports here, you will likely also
# have to change the VirtualHost statement in
# /etc/apache2/sites-enabled/000-default.conf
Listen 80
Listen 81
<IfModule ssl_module>
Listen 443
</IfModule>
<IfModule mod_gnutls.c>
Listen 443
</IfModule>
# vim: syntax=apache ts=4 sw=4 sts=4 sr noet
And everything works fine until in a several days I always get 503 Service Unavailable error page. and this is written in error.log before error occurs
[Sun Oct 25 21:22:27.779422 2015] [core:error] [pid 14595] [client 38.104.233.252:45239] AH00126: Invalid URI in request GET HTTP/1.1 HTTP/1.1
[Mon Oct 26 02:30:20.925532 2015] [core:error] [pid 15416] [client 190.252.95.102:53508] AH00126: Invalid URI in request GET: index.php HTTP/1.0
[Mon Oct 26 08:22:27.771751 2015] [proxy:error] [pid 15402] (111)Connection refused: AH00957: HTTP: attempt to connect to 127.0.1.1:8080 (mypage.com) failed
[Mon Oct 26 08:22:27.774040 2015] [proxy:error] [pid 15402] AH00959: ap_proxy_connect_backend disabling worker for (mypage.com) for 0s
[Mon Oct 26 08:22:27.774111 2015] [proxy_http:error] [pid 15402] [client 5.28.160.27:48692] AH01114: HTTP: failed to make connection to backend: mypage.com
[Mon Oct 26 10:55:51.655213 2015] [proxy:error] [pid 15406] (111)Connection refused: AH00957: HTTP: attempt to connect to 127.0.1.1:8080 (mypage.com) failed
[Mon Oct 26 10:55:51.655422 2015] [proxy:error] [pid 15406] AH00959: ap_proxy_connect_backend disabling worker for (mypage.com) for 0s
[Mon Oct 26 10:55:51.655470 2015] [proxy_http:error] [pid 15406] [client 169.57.5.20:60000] AH01114: HTTP: failed to make connection to backend: mypage.com
[Mon Oct 26 13:32:00.442031 2015] [proxy:error] [pid 15408] (111)Connection refused: AH00957: HTTP: attempt to connect to 127.0.1.1:8080 (mypage.com) failed
[Mon Oct 26 13:32:00.442356 2015] [proxy:error] [pid 15408] AH00959: ap_proxy_connect_backend disabling worker for (mypage.com) for 0s
[Mon Oct 26 13:32:00.442413 2015] [proxy_http:error] [pid 15408] [client 217.168.189.15:50222] AH01114: HTTP: failed to make connection to backend: mypage.com, referer: http://mypage.com/admn
[Mon Oct 26 13:32:12.245050 2015] [proxy:error] [pid 15402] (111)Connection refused: AH00957: HTTP: attempt to connect to 127.0.1.1:8080 (mypage.com) failed
[Mon Oct 26 13:32:12.245179 2015] [proxy:error] [pid 15402] AH00959: ap_proxy_connect_backend disabling worker for (mypage.com) for 0s
[Mon Oct 26 13:32:12.245190 2015] [proxy_http:error] [pid 15402] [client 217.168.189.15:50225] AH01114: HTTP: failed to make connection to backend: mypage.com, referer: http://mypage.com/admn
[Mon Oct 26 13:34:44.343614 2015] [mpm_prefork:notice] [pid 991] AH00169: caught SIGTERM, shutting down
[Mon Oct 26 13:36:07.703185 2015] [mpm_prefork:notice] [pid 991] AH00163: Apache/2.4.7 (Ubuntu) PHP/5.5.9-1ubuntu4.11 configured -- resuming normal operations
[Mon Oct 26 13:36:07.708761 2015] [core:notice] [pid 991] AH00094: Command line: '/usr/sbin/apache2'
[Tue Oct 27 01:20:23.236327 2015] [mpm_prefork:notice] [pid 991] AH00169: caught SIGTERM, shutting down
[Tue Oct 27 01:20:24.265160 2015] [mpm_prefork:notice] [pid 3247] AH00163: Apache/2.4.7 (Ubuntu) PHP/5.5.9-1ubuntu4.11 configured -- resuming normal operations
[Tue Oct 27 01:20:24.265243 2015] [core:notice] [pid 3247] AH00094: Command line: '/usr/sbin/apache2'
[Tue Oct 27 01:41:17.177723 2015] [mpm_prefork:notice] [pid 3247] AH00169: caught SIGTERM, shutting down
[Tue Oct 27 01:41:18.219244 2015] [mpm_prefork:notice] [pid 11636] AH00163: Apache/2.4.7 (Ubuntu) PHP/5.5.9-1ubuntu4.11 configured -- resuming normal operations
[Tue Oct 27 01:41:18.219351 2015] [core:notice] [pid 11636] AH00094: Command line: '/usr/sbin/apache2'
After I restart my machine it works fine again. Then in 7-10 days it crashes again. Tried a lots of things in internet but always get this error at most in several weeks. Struggling with already for some months.
SELinux is disabled.

Answer 1

The problem is not with Apache because its still serving a 503 page
The problem is with the application running on port number 8080, you are reverse proxying / to http://mypage.com:8080/myapp/ and when Apache is trying to proxy the request its not getting back the response from the 8080 app and so its trowing the message 'Service Unavailable' . Its inferred from the underlying part of the log.
[Mon Oct 26 13:32:00.442031 2015] [proxy:error] [pid 15408] (111)Connection refused: AH00957: HTTP: attempt to connect to 127.0.1.1:8080 (mypage.com) failed
[Mon Oct 26 13:32:00.442356 2015] [proxy:error] [pid 15408] AH00959: ap_proxy_connect_backend disabling worker for (mypage.com) for 0s
[Mon Oct 26 13:32:00.442413 2015] [proxy_http:error] [pid 15408] [client 217.168.189.15:50222] AH01114: HTTP: failed to make connection to backend: mypage.com, referer: http://mypage.com/admn
[Mon Oct 26 13:32:12.245050 2015] [proxy:error] [pid 15402] (111)Connection refused: AH00957: HTTP: attempt to connect to 127.0.1.1:8080 (mypage.com) failed
So check and post(if necessary) the logs of the server running on port number 8080