Bug 259607
| Summary: | prometheus_sysctl_exporter: Need better encoding support for sysctl OIDs | ||
|---|---|---|---|
| Product: | Base System | Reporter: | Xin LI <delphij> |
| Component: | bin | Assignee: | Xin LI <delphij> |
| Status: | Closed FIXED | ||
| Severity: | Affects Some People | CC: | asomers, devinrsmith, dor.bsd, freebsd, fs, grahamperrin, lwhsu |
| Priority: | --- | Flags: | asomers:
mfc-stable13+
asomers: mfc-stable12- |
| Version: | CURRENT | ||
| Hardware: | Any | ||
| OS: | Any | ||
Hi, Are these errors actually from the FreeBSD `prometheus_sysctl_exporter`? The `sysctl_` prefix suggests so. Node Exporter doesn't appear to export all of the sysctls anywhere and the metrics it does expose for ZFS and other sysctl based things are very specifically selected and named to avoid collisions. prometheus_sysctl_exporter does appear to show this unfortunate problem: $ prometheus_sysctl_exporter | grep l2arc | sort sysctl_vfs_zfs_l2arc_feed_again 1 sysctl_vfs_zfs_l2arc_feed_again 1 sysctl_vfs_zfs_l2arc_feed_min_ms 200 sysctl_vfs_zfs_l2arc_feed_min_ms 200 Are you using the Node Exporter to export these `prometheus_sysctl_exporter` metrics via the --collector.textfile.directory feature, perhaps? -David Thanks, I've created a patch for this at https://reviews.freebsd.org/D32886 . *** Bug 253862 has been marked as a duplicate of this bug. *** A commit in branch main references this bug: 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 That is used by ZFS sysctls that have been replaced by others, many of which alias to the same Prometheus metric name (like "vfs.zfs.arc_max" and "vfs.zfs.arc.max").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 sys/netinet/tcp_log_buf.c | 33 +++++++++++----------- .../prometheus_sysctl_exporter.c | 11 ++++++-- 2 files changed, 26 insertions(+), 18 deletions(-) A commit in branch stable/13 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=e4f508d5a211e99dd6179794b51fefa329886be3 commit e4f508d5a211e99dd6179794b51fefa329886be3 Author: Alan Somers <asomers@FreeBSD.org> AuthorDate: 2022-04-18 21:29:37 +0000 Commit: Alan Somers <asomers@FreeBSD.org> CommitDate: 2022-05-12 20:40:05 +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 Sponsored by: Axcient Reviewed by: delphij,rew,thj Differential Revision: https://reviews.freebsd.org/D34952 (cherry picked from commit 8c47d8f53854825d8e8591ccd06e32b2c798f81c) sys/netinet/tcp_log_buf.c | 33 +++++++++++----------- .../prometheus_sysctl_exporter.c | 11 ++++++-- 2 files changed, 26 insertions(+), 18 deletions(-) A commit in branch stable/12 references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=b524667411e93d1e828bbaca03d96bb8637a5357 commit b524667411e93d1e828bbaca03d96bb8637a5357 Author: Alan Somers <asomers@FreeBSD.org> AuthorDate: 2022-04-18 21:29:37 +0000 Commit: Alan Somers <asomers@FreeBSD.org> CommitDate: 2022-08-20 01:03:31 +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 Sponsored by: Axcient Reviewed by: delphij,rew,thj Differential Revision: https://reviews.freebsd.org/D34952 (cherry picked from commit 8c47d8f53854825d8e8591ccd06e32b2c798f81c) sys/netinet/tcp_log_buf.c | 33 +++++++++++----------- .../prometheus_sysctl_exporter.c | 11 ++++++-- 2 files changed, 26 insertions(+), 18 deletions(-) |
node_exporter is spamming syslog with: level=error ts=2021-11-02T06:18:08.285Z caller=stdlib.go:105 msg="error gathering metrics: 11 error(s) occurred:\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_write_boost\" { untyped:<value:8.388608e+06 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_arc_max\" { untyped:<value:1.2884901888e+10 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_feed_min_ms\" { untyped:<value:200 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vm_uma_tcp_log_bucket_size\" { untyped:<value:30 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_write_max\" { untyped:<value:8.388608e+06 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_feed_again\" { untyped:<value:1 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_norw\" { untyped:<value:0 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_noprefetch\" { untyped:<value:1 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_arc_min\" { untyped:<value:0 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_feed_secs\" { untyped:<value:1 > } was collected before with the same name and label values\n* [from Gatherer #2] collected metric \"sysctl_vfs_zfs_l2arc_headroom\" { untyped:<value:2 > } was collected before with the same name and label values" The problem is that some ZFS values are exported from two OIDs, for example: vfs.zfs.l2arc_feed_min_ms: 200 vfs.zfs.l2arc.feed_min_ms: 200 But node_exporter is aliasing "." to "_" unconditionally. To get a list of all affected sysctl OIDs, one can use: sysctl -da | grep -E \("$(sysctl -Na | sed -e s,\\.,_,g | sort | uniq -c | sort -n | awk '{ if ($1 >1) print $2; }' | sed -e s,_,.,g | paste -sd \| -)"\): and on FreeBSD 13.0-RELEASE-p4, I got: vm.uma.tcp_log_bucket.size: Allocation size vm.uma.tcp_log.bucket_size: Desired per-cpu cache size vfs.zfs.arc_max: max arc size (LEGACY) vfs.zfs.arc_min: min arc size (LEGACY) vfs.zfs.l2arc_norw: no reads during writes (LEGACY) vfs.zfs.l2arc_feed_again: turbo warmup (LEGACY) vfs.zfs.l2arc_noprefetch: don't cache prefetch bufs (LEGACY) vfs.zfs.l2arc_feed_min_ms: min interval milliseconds (LEGACY) vfs.zfs.l2arc_feed_secs: interval seconds (LEGACY) vfs.zfs.l2arc_headroom: number of dev writes (LEGACY) vfs.zfs.l2arc_write_boost: extra write during warmup (LEGACY) vfs.zfs.l2arc_write_max: max write size (LEGACY) vfs.zfs.l2arc.norw: No reads during writes vfs.zfs.l2arc.feed_again: Turbo L2ARC warmup vfs.zfs.l2arc.noprefetch: Skip caching prefetched buffers vfs.zfs.l2arc.feed_min_ms: Min feed interval in milliseconds vfs.zfs.l2arc.feed_secs: Seconds between L2ARC writing vfs.zfs.l2arc.headroom: Number of max device writes to precache vfs.zfs.l2arc.write_boost: Extra write bytes during device warmup vfs.zfs.l2arc.write_max: Max write bytes per interval vfs.zfs.arc.max: Max arc size vfs.zfs.arc.min: Min arc size So it's not just ZFS. I *think* the proper fix should be to change the translation code to first replace all _ with __, then replace . with _.