On config reload event `vmalert` reloads configuration for every group. While
it works for simple configurations, the more complex and heavy installations may
suffer from frequent config reloads.
The change introduces the `checksum` field for every group and is set to md5 hash
of yaml configuration. The checksum will change if on any change to group
definition like rules order or annotation change. Comparing the `checksum` field
on config reload event helps to detect if group should be updated.
The groups update is now done concurrently, so reload duration will be limited by
the slowest group now.
Partially solves #691 by improving config reload speed.
This should reduce disk space usage when scraping targets containing metrics with identical names
such as `node_cpu_seconds_total`, histograms, quantiles, etc.
Expose `vm_timestamps_blocks_merged_total` and `vm_timestamps_bytes_saved_total` metrics for monitoring
the effectiveness of timestamp blocks merging.
These functions returns the number of raw samples that don't exceed `le` or are bigger than `gt`.
These functions are complement to already existing `share_le_over_time(m[d], le)` and `share_gt_over_time(m[d], gt)`.
* VMAlert start with empty rules dir
There are some applications (operator for instance), that generates alerts configuration at runtime
and vmalert must start correctly without rules to support this behaviour.
Later application will add rules files and send SIGHUP to vmalert,
which will trigger reading rules files and start rules exectuion.
Removing rules files with SIGHUP signal must stop rules execution and
vmalert will wait for new rules.
* imports sorted
* added test cases for empty rules, removed blank line
* fixed imports conflict
* updated tests
* feat: spread load of rule evaluation by group when starting new groups
* review: reduce the resulting diff.
* Update app/vmalert/group.go
Co-authored-by: Roman Khavronenko <hagen1778@gmail.com>
Co-authored-by: Aliaksandr Valialkin <valyala@gmail.com>
Co-authored-by: Roman Khavronenko <hagen1778@gmail.com>
Description for `-rule` flag uses as example specific chars like asterisks
which could be interpreted wrong by different shells. To avoid this, description
now contains quoted flag values.
See also #708
The previous notion was inconsistent with what `decimal.Round` does.
According to [wiki](https://en.wikipedia.org/wiki/Significant_figures) rounding
applied to all significant figures, not just decimal ones.
* app/vmalert: extend metrics set exported by `vmalert` #573
New metrics were added to improve observability:
+ vmalert_alerts_pending{alertname, group} - number of pending alerts per group
per alert;
+ vmalert_alerts_acitve{alertname, group} - number of active alerts per group
per alert;
+ vmalert_alerts_error{alertname, group} - is 1 if alertname ended up with error
during prev execution, is 0 if no errors happened;
+ vmalert_recording_rules_error{recording, group} - is 1 if recording rule
ended up with error during prev execution, is 0 if no errors happened;
* vmalert_iteration_total{group, file} - now contains group and file name labels.
This should improve control over specific groups;
* vmalert_iteration_duration_seconds{group, file} - now contains group and file name labels. This should improve control over specific groups;
Some collisions for alerts and recording rules are possible, because neither
group name nor alert/recording rule name are unique for compatibility reasons.
Commit contains list of TODOs for Unregistering metrics since groups and rules
are ephemeral and could be removed without application restart. In order to
unlock Unregistering feature corresponding PR was filed - https://github.com/VictoriaMetrics/metrics/pull/13
* app/vmalert: extend metrics set exported by `vmalert` #573
The changes are following:
* add an ID label to rules metrics, since `name` collisions within one group is
a common case - see the k8s example alerts;
* supports metrics unregistering on rule updates. Consider the case when one rule
was added or removed from the group, or the whole group was added or removed.
The change depends on https://github.com/VictoriaMetrics/metrics/pull/16
where race condition for Unregister method was fixed.
