Nginx requests, memory usage and connections statistics with Munin
Introduction
These three perl scripts are Munin plugins for monitoring the nginx HTTP server.
nginx_status
Based on the one provided in the Debian munin-node package. Which is itself a modified version of the one available at the Munin Plugin Exchange. It shows the connection status for nginx.
Presents the values returned by nginx, using the http_stub_status module, are respectively, the number of:
connections initiated, connections handled, requests served
nginx_connection_request
Presents the number of requests served by connection handled by nginx. The requests-connection ratio handled by the server is the ratio:
requests served / connections handled
This is implemented as a RRDtool datasource of type GAUGE, the
default type for Munin.
nginx_request
Based on the one provided in the Debian munin-node package. Which is itself a modified version of the one available at the Munin Plugin Exchange.
It uses a derivative (technically a finite difference) to compute the connection rate value.
nginx_memory
Based on a previous plugin by AkyRhO. It uses ps and awk to get
the memory used by the master and worker processes of nginx.
Installation & Configuration
- Copy all the scripts to
/etc/munin/plugins. - Restart the munin-node daemon:
/etc/init.d/munin-node restart. - Done. You should now start to see a new section nginx in your Munin pages with the corresponding graphs.
- All scripts have POD documentation. Issue
perldoc <script name>to read them.
Environment Settings
Both nginx_request and nginx_status accept two environment
variables:
- URL: the URL of the nginx status data. The default value is:
http://hostname/nginx_status - UA: the User Agent that the plugin sends in the HTTP header. Since most sites block the libwww-* user agent to get rid of bad bots and mostly up to no good scanners, the scripts send a different User Agent to get around that.
Both variables can be specified in the
/etc/munin/plugin-conf.d/munin-node file.
Something like this for altering the URL:
[nginx_status]
env.url=http://hostname:8888/nginx-status nginx_status
[nginx_connection_request]
env.url=http://hostname:8888/nginx-status nginx_status
[nginx_request]
env.url=http://hostname:8888/nginx-status nginx_status
Add env.ua for altering the User Agent.
Don’t forget to restart the munin-node daemon as described in step 2 of the installation instructions above.
Note: the github handling of Org mode markup is broken. Therefore
the [nginx_status] [nginx_connection_request] and
[nginx_request] lines are separate from the lines specifying the
environment variables.
It’s not github’s responsibility but rather a bug in Org-Ruby.