This post explains how to configure munin on a single Ubuntu 14.04 server that uses nginx.
sudo apt-get update
sudo apt-get install nginx
Monitoring is supposed to save time by debugging and predicting / avoiding catastrophes. However, setting up munin on Ubuntu was a time-consuming trial-and-error process for me. The official instructions and various blog posts that cover this topic skip important steps, such as having monit's FastCGI processes start automatically at boot time. I have documented the setup that worked for me, hoping that others can reuse my work.
Ubuntu packages
Run the following command to install the packages needed for munin.
sudo apt-get install munin munin-node spawn-fcgi libcgi-fast-perl
The following sections configure the munin packages.
Munin configuration
Write the munin configuration below to /etc/munin/munin-conf.d/90-fcgi
graph_strategy cgi
html_strategy cgi
cgiurl_graph /munin/munin-cgi-graph
NGINX configuration
Write the nginx configuration below to /etc/nginx/sites-available/munin.conf
server {
#listen 443 ssl;
listen 7000;
charset utf-8;
#server_name munin.your-domain.com;
location ~ ^/munin/munin-cgi-graph/ {
fastcgi_split_path_info ^(/munin/munin-cgi-graph)(.*);
fastcgi_param PATH_INFO $fastcgi_path_info;
fastcgi_pass unix:/var/run/munin/fastcgi-graph.sock;
include fastcgi_params;
}
location /munin/static/ {
alias /etc/munin/static/;
expires modified +1w;
}
location /munin/ {
fastcgi_split_path_info ^(/munin)(.*);
fastcgi_param PATH_INFO $fastcgi_path_info;
fastcgi_pass unix:/var/run/munin/fastcgi-html.sock;
include fastcgi_params;
}
location / {
rewrite ^/$ munin/ redirect; break;
}
}
This configuration assumes that you have a DNS entry set aside for reaching the monit pages. I have separate DNS entries for all my applications, and they're all CNAMEs for the (same) machine that they're running on.
Once you're done tweaking the script, reload nginx.
sudo /etc/init.d/nginx reload
FastCGI daemons
Write the script below to /etc/init.d/munin-fcgi
#!/bin/bash
### BEGIN INIT INFO
# Provides: munin-fcgi
# Required-Start: $remote_fs $syslog $network
# Required-Stop: $remote_fs $syslog $network
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Start munin FCGI processes at boot time
# Description: Start the FCGI processes behind http://munin.*/
### END INIT INFO
graph_pidfile="/var/run/munin/fcgi_graph.pid"
# Ubuntu 12.10: /usr/lib/cgi-bin/munin-cgi-graph
graph_cgi="/usr/lib/munin/cgi/munin-cgi-graph"
html_pidfile="/var/run/munin/fcgi_html.pid"
# Ubuntu 12.10: /usr/lib/cgi-bin/munin-cgi-html
html_cgi="/usr/lib/munin/cgi/munin-cgi-html"
retval=0
. /lib/lsb/init-functions
start() {
echo -n "Starting munin graph FastCGI: "
start_daemon -p ${graph_pidfile} /usr/bin/spawn-fcgi -u munin -g munin \
-s /var/run/munin/fastcgi-graph.sock -U www-data ${graph_cgi}
echo
echo -n "Starting munin html FastCGI: "
start_daemon -p ${html_pidfile} /usr/bin/spawn-fcgi -u munin -g munin \
-s /var/run/munin/fastcgi-html.sock -U www-data ${html_cgi}
echo
retval=$?
}
stop() {
echo -n "Stopping munin graph FastCGI: "
killproc -p ${graph_pidfile} ${graph_cgi} -QUIT
echo
echo -n "Stopping munin html FastCGI: "
killproc -p ${html_pidfile} ${html_cgi} -QUIT
echo
retval=$?
}
case "$1" in
start)
start
;;
stop)
stop
;;
restart)
stop
start
;;
*)
echo "Usage: munin-fcgi {start|stop|restart}"
exit 1
;;
esac
exit $retval
Make the script executable, and fix some permissions while you're at it.
sudo chmod +x /etc/init.d/munin-fcgi
sudo chown munin /var/log/munin/munin-cgi-*
Now that the init.d script is in place, start it and have it run on every boot.
sudo /etc/init.d/munin-fcgi start
sudo update-rc.d munin-fcgi defaults
Debugging
You should be able to point your browser to http://[ip_address]:7000 and see many graphs. If that doesn't work out, the logs below should give you a clue as to what went wrong.
/var/log/nginx/error.log
/var/log/munin/munin-cgi-graph.log
/var/log/munin/munin-cgi-html.log
Conclusion
I hope that you have found my post useful, and I hope that it helped you get your munin monitoring setup up and running in a manner of minutes.
