* vmalert: fix nil map assignment
The storage instance with nil map params was created for remote-read purposes.
And before change 7a9ae9de0d this map was ignored in ApplyParams.
Now, it started to be used and vmalert panics in runtime.
The fix properly inits map for at `NewVMStorage` and verifies it is not nil
on assignment in `ApplyParams`.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: add to changelog
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: properly clone Storage params
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: properly clone Storage params
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: properly clone Storage params
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The fix addresses a case when vmalert is configured with a group
which has `name`, but doesn't have `rules` configured. In this
case it still returns a `nil` instead of `[]` slice.
Fixing this via current commit.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4221
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Previously, metric `vmalert_alerting_rules_last_evaluation_series_fetched`
would be set to 0 for const expressions, because const expression do not match
any series. This may result into a confusion: no series were matched but response isn't empty.
The change updates the logic behind metric: if no series were matched but there are samples
in response - use amount of samples as number of series.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: expand rule groups on anchor click
before, anchor click was only updating the URL.
To expand the group, user had to click on rule's block.
Now, group will toggle automatically.
* vmalert: allow filtering group in web UI
The new filter allows to filter groups and rules within
groups by: errors only or noMatch only.
The filtering supposed to help navigating big numbers of groups/rules.
Filtering is reflected in URL, so can be shared as a link.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
app/vmalert: detect alerting rules which don't match any series at all
vmalert starts to understand /query responses which contain object:
```
"stats":{"seriesFetched": "42"}
```
If object is present, vmalert parses it and populates a new field
`SeriesFetched`. This field is then used to populate the new metric
`vmalert_alerting_rules_last_evaluation_series_fetched` and to
display warnings in the vmalert's UI.
If response doesn't contain the new object (Prometheus or
VictoriaMetrics earlier than v1.90), then `SeriesFetched=nil`.
In this case, UI will contain no additional warnings.
And `vmalert_alerting_rules_last_evaluation_series_fetched` will
be set to `-1`. Negative value of the metric will help to compile
correct alerting rule in follow-up.
Thanks for the initial implementation to @Haleygo
See https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4056
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4039
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Properly return empty slices instead of nil for `/api/v1/rules` and `/api/v1/alerts` API handlers.
This improves compatibility with Grafana.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4221
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Supports using `**` for `-rule` and `-rule.templates`: `dir/**/*.tpl` loads contents of dir and all subdirectories recursively.
See: #4041
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Artem Navoiev <tenmozes@gmail.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
Templating of `-external.alert.source` is not expected to have access to the query which was causing runtime error when query function was passed as nil.
See: #4181
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/httpserver: introduce `-http.maxConcurrentRequests` command-line flag
Introduce `-http.maxConcurrentRequests` command-line flag to protect
VM components from resource exhaustion during unexpected spikes of HTTP requests.
By default, the new flag's value is set to 0 which means no limits are applied.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/httpserver: mention http.maxConcurrentRequests in docs
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: retry datasource requests with EOF or unexpected EOF errors
Retry failed read request on the closed connection one more time.
This may improve rules execution reliability when connection
between vmalert and datasource closes unexpectedly.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: fix old tests
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The change adds a new field `seriesFetched` to EvalConfig object.
Since EvalConfig object can be copied inside `Exec`,
`seriesFetched` is a pointer which can be updated by all copied
objects.
The reason for having stats is that other components, like vmalert,
could benefit from this information.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* vmalert: support logs suppressing during config reloads
The change is mostly required for ENT version of vmalert,
since it supports object-storage for config files.
Reading data from object storage could be time-consuming,
so vmalert emits logs to track the progress.
However, these logs are mostly needed on start or on
manual config reload. Printing these logs each time
`rule.configCheckInterval` is triggered would too verbose.
So the change allows to control logs emitting during
config reloads.
Now, logs are emitted during start up or when SIGHUP is receieved.
For periodicall config checks logs emitted by config pkg are suppressed.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: review fixes
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The change also introduces `List` method to `FS` interface.
The `List` method can be used for wildcard support in object storage FS.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
- Sync the description for -httpListenAddr.useProxyProtocol command-line flag at vmagent and vmauth,
so it is consistent with the description at vmauth and victoria-metrics
- Add a sample of panic text to docs/CHANGELOG.md, so it could be googled
- Mention the -httpListenAddr.useProxyProtocol command-line flag in the description for the bugfix
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3335
Each group in vmalert starts with an artifical delay to avoid
thundering herd problem. For some groups with high evaluation
intervals, the delay could be significant.
If during this delay user will remove the group from the config
and hot-reload it - vmalert will have to wait until the delay
ends. This results into slow config reloading and UI hang.
The change moves the start-delay logic back to the group's
`start` method. Now, group can immediately exit from the
delay when `group.close()` method is called.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
When group's update() or close() method is called, the group
still need to wait for its current evaluation to finish.
Sometimes, evaluation could take a significant amount of time
which slows configuration update or vmalert's graceful shutdown.
The change interrupts current evaluation in order to speed up
the graceful shutdown or config update procedures.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
- Document the change at docs/CHANGELOG.md
- Add `Reading rules from object storage` section to docs/vmalert.md
- Add `s3` prefix to command-line flags related to the configuration of s3 and gcs clients
- Explicitly mention that reading rules from object storage is supported only in enterprise version
* vmalert: support object storage for rules
Support loading of alerting and recording rules from object
storages `gcs://`, `gs://`, `s3://`.
* review fixes
* vmalert: use group's ID in UI to avoid collisions
Identical group names are allowed. So we should used IDs
for various groupings and aggregations in UI.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: prevent disabling state updates tracking
The minimum number of update states to track is now set to 1.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: properly update `debug` and `update_entries_limit` params on hot-reload
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: display `debug` field for rule in UI
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: exclude `updates` field from json marhsaling
This field isn't correctly marshaled right now.
And implementing the correct marshaling for it doesn't
seem right, since json representation is mostly used
by systems like Grafana. And Grafana doesn't expect this
field to be present.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* fix test for disabled state
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* fix test for disabled state
Signed-off-by: hagen1778 <roman@victoriametrics.com>
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: speed up state restore procedure on start
Alerts state restore procedure has been changed to become asynchronous.
It doesn't block groups start anymore which significantly improves vmalert's startup time.
Instead, state restore is called by each group in their goroutines after the first rules
evaluation.
While previously state restore attempt was made for all loaded alerting rules,
now it is called only for alerts which became active after the first evaluation.
This reduces the amount of API calls to the configured remote read URL.
This also means that `remoteRead.ignoreRestoreErrors` command-line flag becomes deprecated now
and will have no effect if configured.
See relevant issue https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2608
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* make lint happy
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* Apply suggestions from code review
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Stress the importance of specifying of all Alertmanager
URLs in vmalert's `-notifier.url` or `notifier.config`
if it runs in cluster mode.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3547
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Allow configuring the default number of stored rule's update states in memory
via global `-rule.updateEntriesLimit` command-line flag or per-rule via rule's
`update_entries_limit` configuration param.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* app/vmbackupmanager: add metrics for better observability, include more information to `/api/v1/backups` API call response
* app/vmbackupmanager: drop old metrics before creating new ones
* app/vmbackupmanager: use `_total` postfix for counter metrics
* app/vmbackupmanager: remove `_total` postfix for gauge-like metrics
* app/vmbackupmanager: add `_last_run_failed` metrics for backups and retention
* app/vmbackupmanager: address review feedback
* app/vmbackupmanager: fix metric name
* app/vmbackupmanager: address review feedback, remove background updates of metrics, add restoring state of `_last_run_failed` metric from remote storage
* app/vmbackupmanager: improve performance for backup size calculation
* app/vmbackupmanager: refactor backup and retention runs to deduplicate each run logic
* {app/vmbackupmanager,lib/formatutil}: move HumanizeBytes into lib package
* app/vmbackupmanager: fix creating new metrics instead of reusing existing ones
* lit/formatutil: add comment to make linter happy
* app/vmbackupmanager: address review feedback
The system links are absolute, e.g. they start from `/`, so there are high chances
they won't work as expected when requested via proxy such as vmselect with -vmalert.proxyURL
command-line flag.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/3424
http.Request was used as a part of state struct
for generating the curl command when viewing the rule's
state changes.
It appears, that holding a referencing is far more expensive
than generating the curl command immediately.
On the test with 40k rules, this change reduces memory
and CPU usage by 50%.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: correctly return error for RW failures
By mistake, in 0989649ad0 the error
for remote write failures weren't return to user.
This change fixes it.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Method `metrics()` now pre-allocates slices for labels
and results from query responses. This reduces the number
of allocations on the hot path for instant requests.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The recent change in modifying default value
of `datasource.queryStep` flag resulted in situation
where replay mode was always running queries with
step=`datasource.queryStep`. When it should always
use rule's evaluation interval.
The fix is related not to replay mode only, but
for all Range requests. Now step param is set
individually for each mode.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* app/vmalert: add `remoteWrite.sendTimeout` command-line flag to configure timeout for sending data to `remoteWrite.url`
* vmalert: remove WriteTimeout from clients Cfg
No need to have it as a part of configuration struct:
* the client isn't used by other packages;
* there are no internal tests to check the WriteTimeout.
* vmalert: remove DisablePathAppend from clients Cfg
No need to have it as a part of configuration struct:
* the client isn't used by other packages;
* there are no internal tests to check the DisablePathAppend.
Co-authored-by: hagen1778 <roman@victoriametrics.com>
- Return meta-labels for the discovered targets via promutils.Labels
instead of map[string]string. This improves the speed of generating
meta-labels for discovered targets by up to 5x.
- Remove memory allocations in hot paths during ScrapeWork generation.
The ScrapeWork contains scrape settings for a single discovered target.
This improves the service discovery speed by up to 2x.
* flag reference update
there is no flag `-datasource.disablePathAppend` and datasource actually checking for `-remoteRead.disablePathAppend`
* update source for doc as well
The default list of alerting rules contains the basic
rules for checking vmalert's health state and is recommended
to use for monitoring vmalert deployments.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Previously the `quotesEscape` function was escaping only double quotes.
This wasn't enough, since the input string could contain other special chars,
which must be escaped when put inside JSON string. For example, carriage return and line feed chars (\n\r),
backslash char, etc. This led to the following issues, which were improperly fixed:
- https://github.com/VictoriaMetrics/VictoriaMetrics/issues/890 - this issue
was "fixed" by introducing the `crlfEscape` function, which led to unnecessary
complications in user templates, while not fixing various corner cases
such as backslash chars in the input string.
See 1de15ad490
- https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3139 - this issue
was "fixed" by urlencoding the whole string passed to -external.alert.source
command-line flag. This led to invalid urls, which couldn't be parsed by Grafana.
See 00c838353d
and 4bd0244599
This commit properly encodes the input string passed to `quotesEscape`, so it can be safely embedded inside JSON strings.
This commit deprecates crlfEscape template function and adds the following new template functions:
- strvalue and stripDomain - these functions are supported by Prometheus, so they were added
for compatibility purposes.
- jsonEscape and htmlEscape for converting the input string to valid quoted JSON string
and for html-escaping the input string, so it could be safely embedded as a plaintext
into html.
This commit also documents all supported template functions at https://docs.victoriametrics.com/vmalert.html#template-functions
The deprecated crlfEscape function isn't documented on purpose, since its usefulness is negative in general case.
This reverts commit 00c838353d.
Reason for revert: it incorrectly fixes the issue https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3139 .
Now `-external.alert.source=explore?orgId=1&left=...` is converted to the following invalid url, which cannot be handled by Grafana:
https://grafana.example.com/explore%3ForgId%3D1%26left%3D...
The next commit will contain the correct fix of the issue - the `quotesEscape` function must
properly escape the string, so it could be embedded into JSON string. This function must
properly escape \n\r chars too. In this case the `crlfEscape` function becomes unnecessary.
Actually, the next commit makes the `crlfEscape` function deprecated.
The message about dropped data still remains at `error` level.
The change supposed to make log message more clear about how
serious it is.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The default value of `-datasource.queryStep` has changed, so we update
the troubleshooting docs accordingly.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Due to auto-refactoring, the filed `state` was automatically
renamed to `ruleState` when the entity with the same name
was renamed in other file. Reverting the change.
https://github.com/VictoriaMetrics/helm-charts/issues/391
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
vmalert: prevent duplicating label `alertname` for notifications
The issue has no impact on alerting procedure. But still needs to be fixed
for clarity.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3053
Signed-off-by: lihaowei <haoweili35@gmail.com>
Sort labels explicitly after calling the ParsedConfigs.Apply() when needed.
This reduces CPU usage when performing metric-level relabeling, where labels' sorting isn't needed.
* Use vm_account_id and vm_project_id labels to be consistent with https://docs.victoriametrics.com/Cluster-VictoriaMetrics.html#multitenancy-via-labels
* Document the feature that vmalert now exposes vm_account_id and vm_project_id
labels if -clusterMode is set.
* Use literal strings instead of string constants for vm_account_id and vm_project_id.
This improves code readability.
The change is supposed to provide additional flexibility for generating alert's
source link based on label values.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Incorrect 301 redirects can be cached by user agents such as web browsers.
This can complicate recovery procedure after the incorrect redirect is fixed,
e.g. web browser cache must be reset.
The related issue - https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1752
Allow configuring authorization params per list of targets
in vmalert's notifier config for `static_configs`.
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2690
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
According to Ruler specification, only labels returned within time series
should be available for use in annotations.
For long time, vmalert didn't respect this rule. And in PR
https://github.com/VictoriaMetrics/VictoriaMetrics/pull/2403
this was fixed for the sake of compatibility. However, this resulted
into users confusion, as they expected all configured and extra labels
to be available - https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3013
This fix allows to use extra labels in Annotations. But in the case of conflicts
the original labels (extracted from time series) are preferred.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* lib/{httpserver,netutil}: allow to define min and max TLS version of the http server
* lib/httpserver: added descriptions about tls supported versions
* lib/netutil: check minimal tls version, added supported tls versions to error
* wip
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
- Clarify the description for -datasource.queryStep command-line flag
- Consistently use a single dash in front of -datasource.queryStep command-line flag
- Update -help output at docs/vmalert.md
- Consistently use single dash in front of command-line flags instead of double dashes.
- Add a warning that too small -search.latencyOffset may lead to incomplete query results.
Change default value for command-line flag `datasource.queryStep` from `0s` to `5m`.
Param `step` is added by vmalert to every rule evaluation request sent to datasource.
Before this change, `step` was equal to group's evaluation interval by default.
Param `step` for instant queries defines how far VM can look back for the last written data point.
The change supposed to improve reliability of the rules evaluation when evaluation interval
is lower than scraping interval.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Now vmalert will print the following messages on dupliсates:
```
"recording rule \"record\"; expr: \"up == 1\"; labels: summary={{ value|query }}" is a duplicate within the group "test"
"alerting rule \"alert\"; expr: \"up == 1\"; labels: description={{ value|query }}" is a duplicate within the group "test"
```
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3127
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: always re-evaluate Annotations
Previously, Annotations were evaluated only:
1. On alert creating.
2. On alert's value change.
This is premature optimization. It was assumed that since annotations
could contain only text with alert's labels or value - there is no need
in spending resources to re-compile Annotations.
Later, template function `query` was added, which can execute
arbitrary queries and return different results on every evaluation.
So if it was used in annotations, it would be executed only on init
or value change.
Another case when optimization caused an issue - annotations hot reload.
In this case, annotations of the active alert won't change even if Rule's
annotations were changed.
This fix enables Annotations re-evaluation on each iteration to resolve
issues above. It would have some impact on performance, but it is unlikely
it will be noticeable.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: add tp Changelog
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The change adds an example of `curl` command to the Rule's page.
The command is generated for each recorded state. It is supposed
user can just copy&execute the command to see what was returned
to vmalert.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
vmalert: add experimental feature of storing Rule's evaluation state
The new feature keeps last 20 state changes of each Rule
in memory. The state are available for view on the Rule's
view page. The page can be opened by clicking on `Details`
link next to Rule's name on the `/groups` page.
States change suppose to help in investigating cases when Rule
doesn't generate alerts or records.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
The reason is to cover vulnerability GO-2022-0969
Found in: net/http@go1.18.5
Fixed in: net/http@go1.19.1
More info: https://pkg.go.dev/vuln/GO-2022-0969
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
- Rename logDebug() to logDebugf() and pass format string together
with format args directly to logDebugf(). This eliminates fmt.Sprintf()
overhead at logDebug() call site when debugging is disabled.
- Format labels in debug message in Prometheus format, e.g. {label1="value1",...labelN="valueN"}
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3025
* vmalert: add `debug` mode for alerting rules
Debug information includes alerts state changes and requests
sent to the datasource. Debug can be enabled only on rule's
level. It might be useful for debugging unexpected
behaviour of alerting rule.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3025
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* vmalert: review fixes
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* Update app/vmalert/alerting.go
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
* vmalert: go fmt
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
The io/ioutil package is deprecated since Go1.16 - see https://tip.golang.org/doc/go1.16#ioutil
VictoriaMetrics requires at least Go1.18, so it is time to remove the io/ioutil from source code
This is a follow-up for 02ca2342ab
ioutil.ReadAll is deprecated since Go1.16 - see https://tip.golang.org/doc/go1.16#ioutil
VictoriaMetrics requires at least Go1.18, so it is OK to switch from ioutil.ReadAll to io.ReadAll.
This is a follow-up for 02ca2342ab
The ioutil.{Read|Write}File is deprecated since Go1.16 -
see https://tip.golang.org/doc/go1.16#ioutil
VictoriaMetrics needs at least Go1.18, so it is safe to remove ioutil usage
from source code.
This is a follow-up for 02ca2342ab
We switch default alert's source link to redirect user
to vmalert's UI instead of previous JSON object. While it breaks
compatibility, it also supposed to improve user's experience.
The old behavior can be achieved by updating `-external.alert.source`
command-line flag.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Other components, such as `vmagent`, mark these flags as sensitive and
hide them from the `/metrics` endpoint by default. This commit adds
similar handling to the `vmalert` component, hiding them by default, to
prevent logging of secrets inappropriately.
Showing of these values is controlled by an additional flag.
Follow up to https://github.com/VictoriaMetrics/VictoriaMetrics/pull/2947
vmalert can be successfully used with datasources
compatible with Prometheus HTTP API. So we remove comments or
notes in Readme which are saying opposite.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
