The previous implementation treated extra labels (global and rule labels) as
separate label set to returned time series labels. Hence, time series always contained
only original labels and alert ID was generated from sorted labels key-values.
Extra labels didn't affect the generated ID and were applied on the following actions:
- templating for Summary and Annotations;
- persisting state via remote write;
- restoring state via remote read.
Such behaviour caused difficulties on restore procedure because extra labels had to be dropped
before checking the alert ID, but that not always worked. Consider the case when expression
returns the following time series `up{job="foo"}` and rule has extra label `job=bar`.
This would mean that restored alert ID will be always different to the real time series because
of collision.
To solve the situation extra labels are now always applied beforehand and `vmalert` doesn't
store original labels anymore. However, this could result into a new error situation.
Consider the case when expression returns two time series `up{job="foo"}` and `up{job="baz"}`,
while rule has extra label `job=bar`. In such case, applying extra labels will result into
two identical time series and `vmalert` will return error:
`result contains metrics with the same labelset after applying rule labels`
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/870
* 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.
Uniqueness of rule is now defined by combination of its name, expression and
labels. The hash of the combination is now used as rule ID and identifies rule within the group.
Set of rules from coreos/kube-prometheus was added for testing purposes to
verify compatibility. The check also showed that `vmalert` doesn't support
`query` template function that was mentioned as limitation in README.
* vmalert: Add recording rules support.
Recording rules support required additional service refactoring since
it wasn't planned to support them from the very beginning. The list
of changes is following:
* new entity RecordingRule was added for writing results of MetricsQL
expressions into remote storage;
* interface Rule now unites both recording and alerting rules;
* configuration parser was moved to separate package and now performs
more strict validation;
* new endpoint for listing all groups and rules in json format was added;
* evaluation interval may be set to every particular group;
* vmalert: uncomment tests
* vmalert: rm outdated TODO
* vmalert: fix typos in README
