Re: git: 8c47d8f53854 - main - prometheus_sysctl_exporter: fix metric aliasing

From: Mateusz Piotrowski <0mp_at_FreeBSD.org>
Date: Tue, 19 Apr 2022 14:22:09 UTC
On 19/04/2022 14:56, Alan Somers wrote:
> The branch main has been updated by asomers:
>
> URL: https://cgit.FreeBSD.org/src/commit/?id=8c47d8f53854825d8e8591ccd06e32b2c798f81c
>
> commit 8c47d8f53854825d8e8591ccd06e32b2c798f81c
> Author:     Alan Somers <asomers@FreeBSD.org>
> AuthorDate: 2022-04-18 21:29:37 +0000
> Commit:     Alan Somers <asomers@FreeBSD.org>
> CommitDate: 2022-04-19 12:56:39 +0000
>
>      prometheus_sysctl_exporter: fix metric aliasing
>      
>      When exporting sysctls to Prometheus, the exporter replaces "." with
>      "_".  This caused several metrics to alias, confusing the Prometheus
>      server.  Fix it by:
>      
>      * Renaming the "tcp_log_bucket" UMA zone to "tcp_log_id_bucket".  Also,
>        rename "tcp_log_node" to "tcp_log_id_node" for consistency.
>      
>      * Not exporting sysctls with "(LEGACY)" in the description.  That is
>        used by ZFS sysctls that have been replaced by others, many of which
>        alias to the same Prometheus metric name (like "vfs.zfs.arc_max" and
>        "vfs.zfs.arc.max").
>      
>      PR:             259607
>      Reported by:    delphij
>      MFC after:      2 weeks
>      Sponsored by:   Axcient
>      Reviewed by:    delphij,rew,thj
>      Differential Revision: https://reviews.freebsd.org/D34952

This should definitely make it to release notes.

Also, should we keep a log of these kind of changes in the history section of the manual pages? I 
find the history logs that systemd folks publish in their manual pages to be quite informative, 
e.g., https://www.man7.org/linux/man-pages//man7/systemd.net-naming-scheme.7.html

Best,

Mateusz