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I am using an Amazon Linux distribution (a recent one). I'm trying to install munin in the local node (just one node, both node and master). So I tried:

$ sudo yum install munin munin-node httpd mod_fcgid

Then I edited /etc/munin/munin.conf:

# cgi on demand
html_strategy cgi
graph_strategy cgi

Then I activated the service:

$ sudo chkconfig munin-node on

I checked the version:

$ munin-node-configure --version
Version:
    This is munin-node-configure (munin-node) v2.0.20.
[... more text here ...]

I ensured the munin.conf had the ScriptAlias directive:

<directory /var/www/html/munin>

AuthUserFile /etc/munin/munin-htpasswd
AuthName "Munin"
AuthType Basic
require valid-user

ExpiresActive On
ExpiresDefault M310
</directory>
ScriptAlias /munin-cgi/munin-cgi-graph /var/www/cgi-bin/munin-cgi-graph

I ensured the password is set to a good password:

$ sudo htpasswd -c /etc/munin/munin-htpasswd MyUser
#stdin < my password

Then I restarted the service:

$ sudo /etc/init.d/munin restart

And my httpd:

$ sudo /etc/init.d/httpd restart

But hitting /munin-cgi/munin-cgi-graph raises a 404. But this 404 is not an Apache-like 404, but a totally empty 404 error, with no content at all, as if it was given by the cgi script. The httpd error_log shows nothing.

What should I check? What's my problem?

Luis Masuelli
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2 Answers2

3

Check if your apache/httpd is loading the fcgid or cgi module.

apachectl -M | grep cgi

Should respond 

cgi_module (shared)

or

fcgid_module (shared)

(or both).

If its not there enable it with

sudo a2enmod cgi
Community
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Pierre DOLIDON
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1

Unfortunately, by saying: "...But hitting /munin-cgi/munin-cgi-graph raises a 404..." you are not reporting the complete URL that raised mentioned 404. Please note that you need to call the munin-cgi-graph CGI with proper parameters and that those parameters will be properly validated by munin itself.

In other words, here on my side, this URL:

https://my.monitoring.server/cgi-bin/munin-cgi-graph/SAN/SAN/SAN_SW_Brocade1-pinpoint=1435589472,1435697472.png?&lower_limit=&upper_limit=&size_x=800&size_y=400

will produce following graph:

enter image description here

while this other URL:

https://my.monitoring.server/cgi-bin/munin-cgi-graph/something_random/here_and_there

will last in the 404 error you probably mentioned:

verzulli@iMac-Chiara:~$ wget https://my.monitoring.server/cgi-bin/munin-cgi-graph/something_random/here_and_there
--2015-06-30 23:02:39--  https://my.monitoring.server/cgi-bin/munin-cgi-graph/something_random/here_and_there
[....]
Richiesta HTTP inviata, in attesa di risposta... 404 Not Found
2015-06-30 23:02:40 ERRORE 404: Not Found.

verzulli@iMac-Chiara:~$

This is an intended behaviour of the munin-cgi-graph CGI. A quick look of the source code will show this:

while (new CGI::Fast) {
    # 1rst thing is to validate the URL. Only a subset of chars are allowed.
    # Return 404 if not compliant, w/o logging.
    [...]
}

Should the rendering process handled by munin-cgi-graph fail, chances are high that something will be logged in /var/log/munin/munin-cgi-graph.log (...your LOG path could be different, according to your own configuration).

As dynamic-graph-generation can be slightly tricky, you could carefully review the documentation here and here.

If problem persists, please, provide further details.

Update 1

As for the proper way to access munin web-interface, please consider that on the munin-server all the monitoring activities are launched by a cron-job (munin-cron) that starts launching a munin-update jobs and ends with a munin-html and munin-graph jobs.

The web-pages are managed by munin-html that will generate/update web pages according to the html-dir directives in the munin.conf file.

A default install could looks like:

  • munin.conf: htmldir /var/www/html/munin

that together with a default Apache install, will let your munin web-interface accessible at http://your.monitoring.server/munin

P.S.: A final personal note: even tough it might be easier to ask for support here on ServerFault, I suggest you to approach your munin/monitoring issues more organically, searching/reading ad-hoc documentation/tutorials. Even if at first it might be more challenging, I guarrantee you that in the long run you will be paid back :-)

Damiano Verzulli
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  • I'm a n00b at Munin. Never used it before and the documentation is quote poor regardin web access. What is the first entry point? Assuming I have a webserver and munin in strategy="cgi"... what's the first url I should manually hit in the browser? – Luis Masuelli Jul 01 '15 at 15:05
  • Difficult to say without checking the CFG. Nevertheless, I guess that a simple "/munin" should be enough. Have you tried starting from there? – Damiano Verzulli Jul 01 '15 at 18:09
  • I've updated my answer so to include some details about web-interface (with also a personal advice) :-) – Damiano Verzulli Jul 01 '15 at 19:02
  • I will try. Last time I saw, visiting such url (i.e. /munin in my webserver, according to path /var/www/munin) showed me an index directory (with /static inside). – Luis Masuelli Jul 02 '15 at 17:45