This reverts commit 5a3abfa041.
Reason for revert: exemplars aren't in wide use because they have numerous issues which prevent their adoption (see below).
Adding support for examplars into VictoriaMetrics introduces non-trivial code changes. These code changes need to be supported forever
once the release of VictoriaMetrics with exemplar support is published. That's why I don't think this is a good feature despite
that the source code of the reverted commit has an excellent quality. See https://docs.victoriametrics.com/goals/ .
Issues with Prometheus exemplars:
- Prometheus still has only experimental support for exemplars after more than three years since they were introduced.
It stores exemplars in memory, so they are lost after Prometheus restart. This doesn't look like production-ready feature.
See 0a2f3b3794/content/docs/instrumenting/exposition_formats.md (L153-L159)
and https://prometheus.io/docs/prometheus/latest/feature_flags/#exemplars-storage
- It is very non-trivial to expose exemplars alongside metrics in your application, since the official Prometheus SDKs
for metrics' exposition ( https://prometheus.io/docs/instrumenting/clientlibs/ ) either have very hard-to-use API
for exposing histograms or do not have this API at all. For example, try figuring out how to expose exemplars
via https://pkg.go.dev/github.com/prometheus/client_golang@v1.19.1/prometheus .
- It looks like exemplars are supported for Histogram metric types only -
see https://pkg.go.dev/github.com/prometheus/client_golang@v1.19.1/prometheus#Timer.ObserveDurationWithExemplar .
Exemplars aren't supported for Counter, Gauge and Summary metric types.
- Grafana has very poor support for Prometheus exemplars. It looks like it supports exemplars only when the query
contains histogram_quantile() function. It queries exemplars via special Prometheus API -
https://prometheus.io/docs/prometheus/latest/querying/api/#querying-exemplars - (which is still marked as experimental, btw.)
and then displays all the returned exemplars on the graph as special dots. The issue is that this doesn't work
in production in most cases when the histogram_quantile() is calculated over thousands of histogram buckets
exposed by big number of application instances. Every histogram bucket may expose an exemplar on every timestamp shown on the graph.
This makes the graph unusable, since it is litterally filled with thousands of exemplar dots.
Neither Prometheus API nor Grafana doesn't provide the ability to filter out unneeded exemplars.
- Exemplars are usually connected to traces. While traces are good for some
I doubt exemplars will become production-ready in the near future because of the issues outlined above.
Alternative to exemplars:
Exemplars are marketed as a silver bullet for the correlation between metrics, traces and logs -
just click the exemplar dot on some graph in Grafana and instantly see the corresponding trace or log entry!
This doesn't work as expected in production as shown above. Are there better solutions, which work in production?
Yes - just use time-based and label-based correlation between metrics, traces and logs. Assign the same `job`
and `instance` labels to metrics, logs and traces, so you can quickly find the needed trace or log entry
by these labes on the time range with the anomaly on metrics' graph.
### Describe Your Changes
related issue:
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/6041
#### Added
- Added service discovery support for Vultr.
#### Docs
- `CHANGELOG.md`, `sd_configs.md`, `vmagent.md` are updated.
#### Note
- Useful links:
- Vultr API:
https://www.vultr.com/api/#tag/instances/operation/list-instances
- Vultr client SDK: https://github.com/vultr/govultr
- Prometheus SD:
https://github.com/prometheus/prometheus/tree/main/discovery/vultr
---
### Checklist
The following checks are mandatory:
- [X] I have read the [Contributing
Guidelines](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/CONTRIBUTING.md)
- [x] All commits are signed and include `Signed-off-by` line. Use `git
commit -s` to include `Signed-off-by` your commits. See this
[doc](https://git-scm.com/book/en/v2/Git-Tools-Signing-Your-Work) about
how to sign your commits.
- [x] Tests are passing locally. Use `make test` to run all tests
locally.
- [x] Linting is passing locally. Use `make check-all` to run all
linters locally.
Further checks are optional for External Contributions:
- [X] Include a link to the GitHub issue in the commit message, if issue
exists.
- [x] Mention the change in the
[Changelog](https://github.com/VictoriaMetrics/VictoriaMetrics/blob/master/docs/CHANGELOG.md).
Explain what has changed and why. If there is a related issue or
documentation change - link them as well.
Tips for writing a good changelog message::
* Write a human-readable changelog message that describes the problem
and solution.
* Include a link to the issue or pull request in your changelog message.
* Use specific language identifying the fix, such as an error message,
metric name, or flag name.
* Provide a link to the relevant documentation for any new features you
add or modify.
- [ ] After your pull request is merged, please add a message to the
issue with instructions for how to test the fix or try the feature you
added. Here is an
[example](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4048#issuecomment-1546453726)
- [x] Do not close the original issue before the change is released.
Please note, in some cases Github can automatically close the issue once
PR is merged. Re-open the issue in such case.
- [x] If the change somehow affects public interfaces (a new flag was
added or updated, or some behavior has changed) - add the corresponding
change to documentation.
Signed-off-by: Jiekun <jiekun.dev@gmail.com>
This code adds Exemplars to VMagent and the promscrape parser adhering
to OpenMetrics Specifications. This will allow forwarding of exemplars
to Prometheus and other third party apps that support OpenMetrics specs.
---------
Signed-off-by: Ted Possible <ted_possible@cable.comcast.com>
- Automatically reload changed TLS root CA pointed by -remoteWrite.tlsCAFile command-line flag
- Automatically reload changed TLS root CA configured via oauth2.tsl_config.ca_file option at -promscrape.config
- Document the change as a feature instead of a bug at docs/CHANGELOG.md
- Simplify the code at lib/promauth, which is responsible for reloading changed TLS root CA files.
- Simplify the usage of lib/promauth.Config.NewRoundTripper() - now it accepts the base http.Transport
instead of a callback, which can change the internal http.Transport.
- Reuse the default tls config if lib/promauth.Config doesn't contain tls-specific configs.
This should reduce memory usage a bit when tls isn't used for scraping big number of targets.
- Do not re-read TLS root CA files on every processed request. Re-read them once per second.
This should reduce CPU usage when scraping big number of targets over https.
- Do not store cert.pem and key.pem files in TestTLSConfigWithCertificatesFilesUpdate, since they can be loaded
from byte slices via crypto/tls.X509KeyPair().
- Remove obsolete comparisons of string representations for authConfig and proxyAuthConfig at areEqualScrapeConfigs().
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5725
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5526
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2171
* lib/{promauth,promscrape}: automatically refresh root CA certificates after changes on disk
Added a custom `http.RoundTripper` implementation which checks for root CA content changes and updates `tls.Config` used by `http.RoundTripper` after detecting CA change.
Client certificate changes are not tracked by this implementation since `tls.Config` already supports passing certificate dynamically by overriding `tls.Config.GetClientCertificate`.
This change implements dynamic reload of root CA only for streaming client used for scraping. Blocking client (`fasthttp.HostClient`) does not support using custom transport so can't use this implementation.
See: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5526
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/promauth/config: update NewRoundTripper API
Update API to allow user to update only parameters required for transport.
Add warning log when reloading Root CA failed.
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/promauth/config: fix mutex acquire logic
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/promauth/config: replace RWMutex with regular mutex to simplify the code
- remove additional mutex used for getRootCABytes - require callee to use mutex
- replace RWMutex with regular mutex
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* lib/promauth/config: refactor
- hold the mutex lock to avoid round tripper being re-created twice
- move recreation logic into separate func to simplify the code
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Nikolay <nik@victoriametrics.com>
* lib/promscrape: respect `0` value for `series_limit` param
Respect `0` value for `series_limit` param in `scrape_config`
even if global limit was set via `-promscrape.seriesLimitPerTarget`.
Previously, `0` value will be ignored in favor of `-promscrape.seriesLimitPerTarget`.
This behavior aligns with possibility to override `series_limit` value via
relabeling with `__series_limit__` label.
Signed-off-by: hagen1778 <roman@victoriametrics.com>
* Update docs/CHANGELOG.md
---------
Signed-off-by: hagen1778 <roman@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
This should smooth CPU and RAM usage spikes related to these periodic tasks,
by reducing the probability that multiple concurrent periodic tasks are performed at the same time.
* lib/promscrape/discovery/kubernetes: fix watcher start order for roles endpoints and endpointslice
Previously the groupWatcher could be mistakenly stopped when requests for pod or services resources take too long.
* remove mislead comment
* docs/sd_configs.md: mention -promscrape.kubernetes.attachNodeMetadataAll flag in the description for attach_metadata section
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4640
* wip
* lib/promscrape/kubernetes: prevent from stopping groupWatcher when there are in-flight apiWatcher.mustStart() calls
groupWatcher is stopped if it has zero registered apiWatchers during 14 seconds.
But such a groupWatcher can be still in use if apiWatcher for `role: endpoints` or `role: endpointslice`
is being registered and the discovery of the associated `pod` and/or `service` objects takes longer
than 14 seconds - see the beginning of groupWatcher.startWatchersForRole() function for details.
Track the number of in-flight calls to apiWatcher.mustStart() and prevent from stopping the associated groupWatcher
if the number of in-flight calls is non-zero.
P.S. postponing the discovery of `pod` and/or `service` objects associated with `endpoints` or `endpointslice` roles
isn't the best solution, since it slows down initial discovery of `endpoints` and `endpointslice` targets.
* typo fix
---------
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
Examples:
1) -metricsAuthKey=file:///abs/path/to/file - reads flag value from the given absolute filepath
2) -metricsAuthKey=file://./relative/path/to/file - reads flag value from the given relative filepath
3) -metricsAuthKey=http://some-host/some/path?query_arg=abc - reads flag value from the given url
The flag value is automatically updated when the file contents changes.
- docs/sd_configs.md: moved hetzner_sd_configs docs to the correct place according to alphabetical order of SD names,
document missing __meta_hetzner_role label.
- lib/promscrape/config.go: added missing MustStop() call for Hetzner SD,
and moved the code to the correct place according to alphabetical order of SD names.
- lib/promscrape/discovery/hetzner: properly handle pagination for hloud API responses,
populate missing __meta_hetzner_role label like Prometheus does.
- Properly populate __meta_hetzner_public_ipv6_network label like Prometheus does.
- Remove unused SDConfig.Token.
- Remove "omitempty" annotation from SDConfig.Role field, since this field is mandatory.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5550
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3154
* fix typos in docs
* add `shard-` prefix to generated links when `-promscrape.cluster.memberURLTemplate` is enabled
Signed-off-by: hagen1778 <roman@victoriametrics.com>
