rrd_use_poller_output not working

wwwdrich · Posted: Mon Mar 24, 2008 4:07 pm Post subject: rrd_use_poller_output not working

I am running boost, so I am trying to get PHP Weathermap 0.95b working with cacti 0.8.7b and the latest boost out of SVN. However, the rrd_use_poller_output option in my config file doesn't appear to be working. As long as the RRD files are up to date my weathermap updates properly, if boost hasn't flushed them then I just see "0" for all of my links.

Here is the only thing I see in my log that appears to be related:
03/24/2008 02:01:15 PM - WEATHERMAP: Poller[0] [Map 1] rwc-desktop.conf: RRD ReadData: poller_output: traffic_in is not a valid RRD filename within this Cacti install.
03/24/2008 02:01:15 PM - WEATHERMAP: Poller[0] [Map 1] rwc-desktop.conf: RRD ReadData: poller_output: traffic_out is not a valid RRD filename within this Cacti install.
03/24/2008 02:01:15 PM - WEATHERMAP: Poller[0] [Map 1] rwc-desktop.conf: ReadData: LINK rwcdc86-1, target: /var/log/cacti/rra/rwc_desktop_switch_rwcdc86_traffic_in_1242.rrd on config line 124 had no valid data, according to WeatherMapDataSource_rrd

And I will see those errors for every link that doesn't get a value.

Any thoughts?

Howie · Posted: Mon Mar 24, 2008 4:37 pm Post subject:

How about if you run with DEBUG logging for a poller cycle? You should get some more information then. It is taking notice of your SET line, because those warnings are from the poller_output part of the deal.

It does take a few cycles to get up to speed with poller_output though - one pass to find the required rrds, and then two more before it has a real value (it needs two values to get a difference). You can see if it's working at all by looking in the weathermap_data table to see if it has anything.

One other thing is that it only works if the path you use to your rrds is the same one Cacti uses (the /var/log looks a little funny). It expects to be able to convert the TARGET back into a <rra_path>/blah.rrd, just like Cacti itself uses.

I am using poller_output with 0.95b OK at the moment (although not with Boost), so I don't think it's a general thing.

wwwdrich · Posted: Mon Mar 24, 2008 4:43 pm Post subject:

I wonder if it's the symlink from the cacti install to /var/log/cacti/rra that is causing it trouble. I'll try changing the path and see if that helps. Here is the debug info, I was just running it with the intention of posting when I saw you post.

wwwdrich · Posted: Mon Mar 24, 2008 4:47 pm Post subject:

The the other possibility -- the SVN version of boost (the only one that works at this point) uses a different poller_output table. It reads everything into poller_output_boost, and it looks like poller_output stays empty. If I could find he code that looking at poller_output I'll point it to the new table and see if that makes any difference.

Howie · Posted: Mon Mar 24, 2008 5:00 pm Post subject:

Howie · Posted: Mon Mar 24, 2008 5:04 pm Post subject:

wwwdrich · Posted: Mon Mar 24, 2008 5:13 pm Post subject:

I just tweaked all of the paths in my config file to match what should be the path in the database - i.e. /var/www/html/cacti/rra instead of where the files really live. Where is it getting rra_path from now? Does cacti calculate it from PHP_SELF? I have also noticed that it is rewriting the URL to ignore the symlink we have at our cacti base -- which is going to make upgrades a nightmare in the future (i.e. .../cacti is a symlink to .../cacti-0.8.7b). This is new behaviour in 0.8.7b, and causes other headaches like making me run the boost tools with full paths instead of as ./blahblah.php.

wwwdrich · Posted: Mon Mar 24, 2008 5:24 pm Post subject:

I think if I can figure out what it wants in path_rra I will have this licked. As an example:

Howie · Posted: Mon Mar 24, 2008 6:12 pm Post subject:

Looks like it will always be $base_path/rra...

wwwdrich · Posted: Tue Mar 25, 2008 9:58 am Post subject:

Ok, I think I see the problem. It looks like weathermap is using the absolute path for the file -- i.e. following the symlink. Whereas, Cacti has the relative path to the file, i.e. /var/www/html/cacti-0.8.7b/rra. So, I see messages like:

Howie · Posted: Tue Mar 25, 2008 11:45 am Post subject:

Weathermap doesn't follow the link. It just tries to replace a chunk of the path with $cacti_root/rra. It doesn't actually look at the FS at all.

So if you use whatever Cacti thinks it's root directory is, in the TARGET, it should all work. This is all it does (line 65 or so, WeathermapDataSource_rrd.php):

wwwdrich · Posted: Tue Mar 25, 2008 1:38 pm Post subject:

I haven't tried it yet (trying to get a different map cleaned up), but it looks like that is the culprit. From the PHP docs:

wwwdrich · Posted: Tue Mar 25, 2008 4:10 pm Post subject:

I can't just comment it out, otherwise db_rrdname isn't set. However, changing it as below fixes it!

Howie · Posted: Tue Mar 25, 2008 4:40 pm Post subject: