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.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5982
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>
(cherry picked from commit 5a3abfa041)
- 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>
- Make sure that invalid/missing TLS CA file or TLS client certificate files at vmagent startup
don't prevent from processing the corresponding scrape targets after the file becomes correct,
without the need to restart vmagent.
Previously scrape targets with invalid TLS CA file or TLS client certificate files
were permanently dropped after the first attempt to initialize them, and they didn't
appear until the next vmagent reload or the next change in other places of the loaded scrape configs.
- Make sure that TLS CA is properly re-loaded from file after it changes without the need to restart vmagent.
Previously the old TLS CA was used until vmagent restart.
- Properly handle errors during http request creation for the second attempt to send data to remote system
at vmagent and vmalert. Previously failed request creation could result in nil pointer dereferencing,
since the returned request is nil on error.
- Add more context to the logged error during AWS sigv4 request signing before sending the data to -remoteWrite.url at vmagent.
Previously it could miss details on the source of the request.
- Do not create a new HTTP client per second when generating OAuth2 token needed to put in Authorization header
of every http request issued by vmagent during service discovery or target scraping.
Re-use the HTTP client instead until the corresponding scrape config changes.
- Cache error at lib/promauth.Config.GetAuthHeader() in the same way as the auth header is cached,
e.g. the error is cached for a second now. This should reduce load on CPU and OAuth2 server
when auth header cannot be obtained because of temporary error.
- Share tls.Config.GetClientCertificate function among multiple scrape targets with the same tls_config.
Cache the loaded certificate and the error for one second. This should significantly reduce CPU load
when scraping big number of targets with the same tls_config.
- Allow loading TLS certificates from HTTP and HTTPs urls by specifying these urls at `tls_config->cert_file` and `tls_config->key_file`.
- Improve test coverage at lib/promauth
- Skip unreachable or invalid files specified at `scrape_config_files` during vmagent startup, since these files may become valid later.
Previously vmagent was exitting in this case.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4959
* fix inconsistent behaviors with prometheus when scraping
1. address https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4959. skip job with wrong syntax in `scrape_configs` with error logs instead of exiting;
2. show error messages on vmagent /targets ui if there are wrong auth configs in `scrape_configs`, previously will print error logs and do scrape without auth header;
3. don't send requests if there are wrong auth configs in:
1. vmagent remoteWrite;
2. vmalert datasource/remoteRead/remoteWrite/notifier.
* add changelogs
* address review comments
* fix ut
Initially, stream parse mode was reading data from response and parsing it on flight. This was causing longer delay to read the whole response and required increasing timeout value to allow data processing while reading. So that 908e35affd increased timeout value to fix this.
But after 74c00a8762 response in stream parse mode is saved into memory and then parsed eliminating necessity of having timeout value higher that for usual scrape.
Updates: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4847
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
(cherry picked from commit 6e8611f301)
- Return immediately on context cancel during the backoff sleep.
This should help with https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3747
- Add a comment describing why the second attempt to obtain the response from remote side
is perfromed immediately after the first attempt.
- Remove fasthttp dependency from lib/promscrape/discoveryutils
- Set context deadline before calling doRequestWithPossibleRetry().
This simplifies the doRequestWithPossibleRetry() a bit.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3293
* fix: do not use exponential backoff for first retry of scrape request (#3293)
* lib/promscrape: refactor `doRequestWithPossibleRetry` backoff to simplify logic
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
* Update lib/promscrape/client.go
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
* lib/promscrape: refactor `doRequestWithPossibleRetry` to make it more straightforward
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
---------
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
This fixes handling of values bigger than 2GiB for the following command-line flags:
- -storage.minFreeDiskSpaceBytes
- -remoteWrite.maxDiskUsagePerURL
- 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.
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 429 status code means that the server is overwhelmed with requests.
The client can retry the request after some wait time.
Implement this strategy for service discovery and scrape requests.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2940
Previously ScrapeConfig.clone() was improperly copying promauth.Secret fields -
their contents was replaced with `<secret>` value.
This led to inability to use passwords and secrets in `-promscrape.config` file.
The bug has been introduced in v1.77.0 in the commit 67b10896d2
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2551
Stream parsing mode can be automatically enabled when scraping targets with big response bodies
exceeding the -promscrape.minResponseSizeForStreamParse , so it must be always initialized.
