Process/procedure for removing display of graphs related to old metrics no longer returned by a plugin

Troubleshooting
1

CMK version: CEE 1.6.0p25
OS version: CentOS 8

We altered a home grown plugin that generates rrd graphed data. Some of the metrics are no longer generated by the new plugin, but the graphs remain. Is there an easy way to remove the old graphs, keep them from showing up? Like editing the .info file, for example? Is there a recommended procedure for this?

2

My experience said that there is no easy way. The problem is that you not only need to modify the .info file but also you need to alter the corresponding rrd file.
For the modification of the rrd file i don’t know a really easy option. The old rrd’s with one rrd for every metric are easy to change → delete all metric files older than some hours and that’s it.

Question add @moritz do you know someone from the Tribe team who can know if there is an easy way to remove unwanted metrics from the monolithic rrd’s?

3

As a worraround for removing the old data from the rrd you can try to set these metrics to auto_graph': False in the checks metrics definition. For example

check_metrics['cve_2021_44228_log4j'] = {
    'errors': {'auto_graph': False},
}
4

It is possible. See here [Check_mk (deutsch)] Performance Data gezielt löschen - #4 by ARTELIS_Monitoring and the following post for metrics that are not at the end of the list.

But it’s in German. Maybe I can write a simple translation by tomorrow.

2 Likes
5

This procedure is what i also know that it works. The most interesting one is to remove a metric not at the end of the rrd.

1 Like
6

This is what my colleague @oscar.najera told me:

Es gibt keinen “easy way”
mit rrdtune kann man Metriken aus dem RRD löschen, und dann kann man die aus der info Datei auch >löschen.
NatĂĽrlich muss der cmc & rrddaemon gestopt sein und alle caches geflushed, sonst has der rrd journal >eine Spalte zu viel und das gibt Probleme, (RRD & CMC haben kein error handling fĂĽr den Fall)

Anastasios kann dir auch erzählen, wie schmerzhaft das ist am RRD was zu ändern.

Not too hard way:
im web local check_metric ĂĽberschreiben

check_metrics[“check_mk-check-with-extra-metric”] = {
“old-metric-I-don’t-want”: {“auto_graph”: False},
**all_other stuff_configured_for_the_check
}

1 Like
7

Wasn’t clear where this had to go. I mean, metric names could be “same” for different things across different hosts. Just doesn’t seem “right”?

At the end of the day, since I had to rewrite my plugin, I just nuked all the rrd stuff and regen’d it.

We didn’t lose too much historical stuff of any worth.

8

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