Keeping specific systemd name labels

[Emre Kiratli]

https://github.com/prometheus/prometheus/issues/3092

This is my current issue i just want to watch mysql,postgresql labels and drop the rest. Did anyone figure this out?

[Emre Kiratli]

^((?!.*myspecificservice.*).)*$  does not work

prom log :

err="parsing YAML file /etc/config/prometheus.yml: error parsing regexp: invalid or unsupported Perl syntax: `(?!`"  

20 Kasım 2020 Cuma tarihinde saat 13:20:18 UTC+3 itibarıyla Emre Kiratli şunları yazdı:

[Matthias Rampke]

Go regexes unfortunately do not support negative matches. I believe you can get the behavior that you need by having a temporary label, and changing it based on the various conditions:

1. you want to keep all metrics by default (action replace, target __tmp_keep, replacement "yes")

2. you want to drop all unit state metrics (action replace, source labels __name__, match "node_systemd_unit_state", target __tmp_keep, replacement "no")

3. you want to keep all unit state metrics where name matches (action replace, source labels [__name__,name], match "node_systemd_unit_state;(mysql|postrgresql).*", target __tmp_keep, replacement yes)

4. act on the temporary label (action keep, source labels _tmp_keep, match "yes")

/MR

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[b.ca...@pobox.com]

As the error says, you are using unsupported regex syntax.  Prometheus supports the syntax of the RE2 library: https://github.com/google/re2/wiki/Syntax

For more complex ways of combining drop/keep expressions, you can use __tmp labels.  Here is an example which doesn't solve your particular problem exactly, but gives an example of how it can be used:

      # On docker hosts we get many tmpfs/aufs filesystem; lots of NFS mounts too,

      # plus ext4 bind mounts under /run/docker/runtime-runs/moby/

      # Drop all of these, except keep node_filesystem_readonly for NFS mounts.

      - source_labels: [__name__, fstype]

        regex: 'node_filesystem_readonly;(nfs|nfs4|.*gluster.*)'

        target_label: __tmp_keep

        replacement: Y

      - source_labels: [__tmp_keep, fstype]

        regex: ';(aufs|tmpfs|nfs|nfs4|fuse.lxcfs|.*gluster.*)'

        action: drop

      - source_labels: [__tmp_keep, mountpoint]

        regex: ';(/run/.*)'

        action: drop

      - regex: '__tmp.*'

        action: labeldrop

I wanted to drop all labels with specific fstype and mountpoint values, *except* I wanted to keep the node_filesystem_readonly metrics for certain filesystem types.