Commit graph

712 commits

Author SHA1 Message Date
helen
c8a96ac241
clean unused code (#5735)
Signed-off-by: helen <haitao.zhang@daocloud.io>
2024-01-31 17:50:36 +00:00
Aliaksandr Valialkin
bc7cf4950b
lib/promscrape: use the standard net/http.Client instead of fasthttp.Client for scraping targets in non-streaming mode
While fasthttp.Client uses less CPU and RAM when scraping targets with small responses (up to 10K metrics),
it doesn't work well when scraping targets with big responses such as kube-state-metrics.
In this case it could use big amounts of additional memory comparing to net/http.Client,
since fasthttp.Client reads the full response in memory and then tries re-using the large buffer
for further scrapes.

Additionally, fasthttp.Client-based scraping had various issues with proxying, redirects
and scrape timeouts like the following ones:

- https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1945
- https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5425
- https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2794
- https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1017

This should help reducing memory usage for the case when target returns big response
and this response is scraped by fasthttp.Client at first before switching to stream parsing mode
for subsequent scrapes. Now the switch to stream parsing mode is performed on the first scrape
after reading the response body in memory and noticing that its size exceeds the value passed
to -promscrape.minResponseSizeForStreamParse command-line flag.
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5567

Overrides https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4931
2024-01-30 18:39:10 +02:00
Aliaksandr Valialkin
c2373a8109
lib/promscrape: fix BenchmarkScrapeWorkScrapeInternal, which has been broken by the commit 65bc460323 2024-01-30 16:06:06 +02:00
Aliaksandr Valialkin
ac5b740750
lib/promscrape/discovery/kubernetes: typo fix in the comment for ContainerStateTerminated struct
This is a follow-up for ef12598ad4
2024-01-24 15:06:46 +02:00
Aliaksandr Valialkin
ef12598ad4
lib/promscrape/discovery/kubernetes: do not generate targets for already terminated pods and containers
Already terminated pods and containers cannot be scraped and will never resurrect,
so there is zero sense in creating scrape targets for them.
2024-01-24 14:57:53 +02:00
Roman Khavronenko
89e3c70ccd
lib/promscrape: respect 0 value for series_limit param (#5663)
* 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>
2024-01-23 13:09:14 +02:00
Aliaksandr Valialkin
3449d563bd
all: add up to 10% random jitter to the interval between periodic tasks performed by various components
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.
2024-01-22 18:40:32 +02:00
Aliaksandr Valialkin
d3ee3e0ef5
Revert "lib/promscrape: do not store last scrape response when stale markers … (#5577)"
This reverts commit cfec258803.

Reason for revert: the original code already doesn't store the last scrape response when stale markers are disabled.
The scrapeWork.areIdenticalSeries() function always returns true is stale markers are disabled.
This prevents from storing the last response at scrapeWork.processScrapedData().

It looks like the reverted commit could also return back the issue https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3660

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5577
2024-01-22 00:43:48 +02:00
Hui Wang
4e3242b02d
lib/promscrape/discovery/kubernetes: fix watcher start order for roles endpoints and endpointslice (#5557)
* 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>
2024-01-21 23:13:15 +02:00
Aliaksandr Valialkin
1f105dde98
all: allow dynamically reading *AuthKey flag values from files and urls
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.
2024-01-21 22:03:38 +02:00
Aliaksandr Valialkin
4eb9926125
lib/promscrape: code cleanup: send stale markers immediately after generating automatic metrics
This cleanup has been extracted from https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5557/files#diff-6b205cf6637d7b65a5c45d9417d08822d4efad94227268cb196f61aa2a0fc0f7
2024-01-21 05:18:22 +02:00
Aliaksandr Valialkin
12f2c5679b
all: consistently clear prompbmarshal.Label by assigning an empty struct instead of zeroing Name and Value individually 2024-01-21 05:11:05 +02:00
Aliaksandr Valialkin
7fba73ce11
lib/promscrape/discovery/kubernetes: add -promscrape.kubernetes.attachNodeMetadataAll command-line flag
This flag allows setting attach_metadata.node=true for all the kubernetes_sd_configs defined at -promscrape.config

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4640

Thanks to wasim-nihal for the initial implementation at https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5593
2024-01-21 03:13:56 +02:00
Aliaksandr Valialkin
74448a7e57
lib/promscrape/discovery/hetzner: follow-up after 03a97dc678
- 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
2024-01-20 17:01:53 +02:00
Hui Wang
cfec258803
lib/promscrape: do not store last scrape response when stale markers … (#5577)
* lib/promscrape: do not store last scrape response when stale markers are disabled

* update changelog
2024-01-20 00:53:41 +08:00
Aliaksandr Valialkin
41932db848
lib/promscrape: cosmetic changes after 3ac44baebe
- Rename mustLoadScrapeConfigFiles() to loadScrapeConfigFiles(), since now it may return error.
- Split too long line with the error message into two lines in order to improve readability a bit.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5508
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5560
2024-01-16 22:29:09 +02:00
Hui Wang
3ac44baebe
exit vmagent if there is config syntax error in scrape_config_files when -promscrape.config.strictParse=true (#5560) 2024-01-16 17:30:02 +08:00
Aliaksandr Valialkin
4b42c8abbb
lib/promscrape/discovery/hetzner: fix golangci-lint warnings after 03a97dc678
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5550
2024-01-15 17:12:40 +02:00
Aleksandr Stepanov
03a97dc678
vmagent: added hetzner sd config (#5550)
* added hetzner robot and hetzner cloud sd configs

* remove gettoken fun and update docs

* Updated CHANGELOG and vmagent docs

* Updated CHANGELOG and vmagent docs

---------

Co-authored-by: Nikolay <nik@victoriametrics.com>
2024-01-15 10:13:22 +01:00
Aliaksandr Valialkin
d2c94a0663
lib/prompbmarshal: switch to github.com/VictoriaMetrics/easyproto 2024-01-14 23:04:45 +02:00
Aliaksandr Valialkin
5a88bc973f
all: use Gauge instead of Counter for *_config_last_reload_successful metrics
This allows exposing the correct TYPE metadata for these labels when the app runs with -metrics.exposeMetadata command-line flag.
See https://github.com/VictoriaMetrics/metrics/pull/61#issuecomment-1860085508 for more details.

This is follow-up for 326a77c697
2023-12-20 14:23:42 +02:00
hagen1778
e0fc5ef140
lib/promscrape: comsetic changes after e373bb84d5
* fix typos in docs
* add `shard-` prefix to generated links when `-promscrape.cluster.memberURLTemplate` is enabled

Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-12-12 11:28:18 +01:00
Aliaksandr Valialkin
b05e1512d4
lib/promscrape: add a wraning when the /service-discovery page contains incomplete list of dropped targets 2023-12-08 19:03:51 +02:00
Aliaksandr Valialkin
e373bb84d5
lib/promscrape: add -promscrape.cluster.memberURLTemplate command-line flag for creating direct links to vmagent instances at /service-discovery page
See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4018#issuecomment-1843811569
2023-12-07 16:04:21 +02:00
Aliaksandr Valialkin
7cb8ed8271
lib/promscrape: show -promscrape.cluster.memberNum values for vmagent instances, which scrape the given dropped target at /service-discovery page
The /service-discovery page contains the list of all the discovered targets
after the commit 487f6380d0 on all the vmagent instances
in cluster mode ( https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets ).

This commit improves debuggability of targets in cluster mode by providing a list of -promscrape.cluster.memberNum
values per each target at /service-discovery page, which has been dropped becasue of sharding,
e.g. if this target is scraped by other vmagent instances in the cluster.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5389
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4018
2023-12-07 00:05:32 +02:00
Aliaksandr Valialkin
67468a0c46
lib/promscrape: show never scraped message for never scraped targets at /targets page 2023-12-06 22:33:39 +02:00
Aliaksandr Valialkin
65bc460323
lib/promscrape: follow-up for 97373b7786
Substitute O(N^2) algorithm for exposing the `vm_promscrape_scrape_pool_targets` metric
with O(N) algorithm, where N is the number of scrape jobs. The previous algorithm could slow down
/metrics exposition significantly when -promscrape.config contains thousands of scrape jobs.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5311
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5335
2023-12-06 17:35:50 +02:00
Hui Wang
97373b7786
vmagent: add vm_promscrape_scrape_pool_targets for scrape jobs like… (#5335)
* vmagent: export `vm_promscrape_scrape_pool_targets` metric to track the number of targets that each scrape_job discovers

* add extra panel for new metric
2023-12-06 15:44:39 +08:00
Aliaksandr Valialkin
487f6380d0
lib/promscrape: show dropped targets because of sharding at /service-discovery page
Previously the /service-discovery page didn't show targets dropped because of sharding
( https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets ).

Show also the reason why every target is dropped at /service-discovery page.
This should improve debuging why particular targets are dropped.

While at it, do not remove dropped targets from the list at /service-discovery page
until the total number of targets exceeds the limit passed to -promscrape.maxDroppedTargets .
Previously the list was cleaned up every 10 minutes from the entries, which weren't updated
for the last minute. This could complicate debugging of dropped targets.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5389
2023-12-01 16:48:48 +02:00
Aliaksandr Valialkin
5034aa0773
app/vmagent: follow-up for 090cb2c9de
- Add Try* prefix to functions, which return bool result in order to improve readability and reduce the probability of missing check
  for the result returned from these functions.

- Call the adjustSampleValues() only once on input samples. Previously it was called on every attempt to flush data to peristent queue.

- Properly restore the initial state of WriteRequest passed to tryPushWriteRequest() before returning from this function
  after unsuccessful push to persistent queue. Previously a part of WriteRequest samples may be lost in such case.

- Add -remoteWrite.dropSamplesOnOverload command-line flag, which can be used for dropping incoming samples instead
  of returning 429 Too Many Requests error to the client when -remoteWrite.disableOnDiskQueue is set and the remote storage
  cannot keep up with the data ingestion rate.

- Add vmagent_remotewrite_samples_dropped_total metric, which counts the number of dropped samples.

- Add vmagent_remotewrite_push_failures_total metric, which counts the number of unsuccessful attempts to push
  data to persistent queue when -remoteWrite.disableOnDiskQueue is set.

- Remove vmagent_remotewrite_aggregation_metrics_dropped_total and vm_promscrape_push_samples_dropped_total metrics,
  because they are replaced with vmagent_remotewrite_samples_dropped_total metric.

- Update 'Disabling on-disk persistence' docs at docs/vmagent.md

- Update stale comments in the code

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5088
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2110
2023-11-25 12:09:44 +02:00
Nikolay
090cb2c9de
app/vmagent: allow to disabled on-disk persistence (#5088)
* app/vmagent: allow to disabled on-disk queue
Previously, it wasn't possible to build data processing pipeline with a
chain of vmagents. In case when remoteWrite for the last vmagent in the
chain wasn't accessible, it persisted data only when it has enough disk
capacity. If disk queue is full, it started to silently drop ingested
metrics.

New flags allows to disable on-disk persistent and immediatly return an
error if remoteWrite is not accessible anymore. It blocks any writes and
notify client, that data ingestion isn't possible.

Main use case for this feature - use external queue such as kafka for
data persistence.
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/2110

* adds test, updates readme

* apply review suggestions

* update docs for vmagent

* makes linter happy

---------

Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
2023-11-24 13:42:11 +01:00
Aliaksandr Valialkin
613b545dfd
lib/promscrape/discovery/kubernetes: propagate possible errors at newAPIWatcher() to the caller
This allows substituting FATAL panics with recoverable runtime errors such as missing or invalid TLS CA file
and/or missing/invalid /var/run/secrets/kubernetes.io/serviceaccount/namespace file.
Now these errors are logged instead of PANIC'ing, so they can be fixed by updating the corresponding files
without the need to restart vmagent.

This is a follow-up for 90427abc65
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5243
2023-10-27 20:24:46 +02:00
Hui Wang
90427abc65
lib/promscrape/discovery/kubernetes: avoid possible panic if given caFile under kubernetes.SDConfig.HTTPClientConfig is not exist (#5243)
follow up d5a599badc
2023-10-27 20:20:22 +02:00
Aliaksandr Valialkin
632d788b63
lib/promscrape/discovery/kubernetes: stop all the url watchers, which belong to a particular groupWatcher, at once
Previously url watchers for pod, service and node objects could be mistakenly closed
when service discovery was set up only for endpoints and endpointslice roles,
since watchers for these roles may start start pod, service and node url watchers
with nil apiWatcher passed to groupWatcher.startWatchersForRole().

Now all the url watchers, which belong to a particular groupWatcher, are stopped at once
when this groupWatcher has no apiWatcher subscribers.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5216

The issue has been introduced in v1.93.5 when addressing https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4850
2023-10-27 13:51:35 +02:00
Hui Wang
7c90ce39cb
do not print redundant error logs when failed to scrape consul or no… (#5239)
* do not print redundant error logs when failed to scrape consul or nomad target
prometheus performs the same because it uses consul lib which just drops the error(1806bcb38c/api/api.go (L1134))
2023-10-27 13:31:55 +08:00
Aliaksandr Valialkin
cdbc06a639
lib/promscrape: do not add a suggestion for enabling TCP6 in error message when the dial address is TCPv4 2023-10-25 17:57:56 -07:00
Dima Lazerka
8b41b506c2
Revert "lib/promscrape: do not add a suggestion for enabling TCP6 in error message when the dial address is TCPv4"
It broke CI (lint)

This reverts commit 5464376d16.
2023-10-25 16:24:31 -07:00
Aliaksandr Valialkin
5464376d16
lib/promscrape: do not add a suggestion for enabling TCP6 in error message when the dial address is TCPv4 2023-10-26 00:29:51 +02:00
Aliaksandr Valialkin
ac933cc423
lib/promscrape: properly track the number of updated service discovery routines inside Config.mustRestart()
This is a follow-up for d5a599badc
2023-10-26 00:06:29 +02:00
Aliaksandr Valialkin
d5a599badc
lib/promauth: follow-up for e16d3f5639
- 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
2023-10-25 23:19:37 +02:00
Aliaksandr Valialkin
c22e3e7b1d
lib/promscrape/discovery/kubernetes/kubeconfig_test.go: make TestParseKubeConfigSuccess test code easier to follow 2023-10-25 23:17:18 +02:00
Aliaksandr Valialkin
eed5206376
lib/promauth: properly parse string contents for ca, cert and key fields at tls_config
Previously yaml parser wasn't accepting string values for these fields,
because it was mistakenly expecting a list of uint8 values instead.
2023-10-25 23:12:21 +02:00
Aliaksandr Valialkin
4afcb2a689
lib/promscrape: move duplicate code from functions, which collect ScrapeWork lists for distinct SD types into Config.getScrapeWorkGeneric()
This removes more than 200 lines of duplicate code
2023-10-25 23:03:40 +02:00
Aliaksandr Valialkin
42dd71bb63
all: consistently use %w instead of %s in when error is passed to fmt.Errorf()
This allows consistently using errors.Is() for verifying whether the given error wraps some other known error.
2023-10-25 21:24:03 +02:00
Hui Wang
e16d3f5639
fix inconsistent behaviors with prometheus when scraping (#5153)
* 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
2023-10-17 17:58:19 +08:00
Aliaksandr Valialkin
b8c267075e
lib/promscrape: add a link to https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets in descriptions for -promscrape.cluster.* command-line flags
This should help users figuring out the purpose of -promscrape.cluster.* command-line flags
2023-10-16 14:46:22 +02:00
Roman Khavronenko
a4bd73ec7e
lib/promscrape: make concurrency control optional (#5073)
* lib/promscrape: make concurrency control optional

Before, `-maxConcurrentInserts` was limiting all calls to `promscrape.Parse`
function: during ingestion and scraping. This behavior is incorrect.
Cmd-line flag `-maxConcurrentInserts` should have effect onl on ingestion.

Since both pipelines use the same `promscrape.Parse` function, we extend it
to make concurrency limiter optional. So caller can decide whether concurrency
should be limited or not.

This commit makes c53b5788b4
obsolete.

Signed-off-by: hagen1778 <roman@victoriametrics.com>

* Revert "dashboards: move `Concurrent inserts` panel to Troubleshooting section"

This reverts commit c53b5788b4.

---------

Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-10-02 21:32:11 +02:00
Aliaksandr Valialkin
859977d591
Revert "lib/promscrape: add metric vm_promscrape_scrapes_skipped_total (#5074)"
This reverts commit 74301cdbf5.

Reason for revert:

vmagent already provides better approach for detecting slow scrape targets via the following query:

    scrape_duration_seconds / scrape_timeout_seconds > 1

This query depends on automatically generated per-target metrics.
See https://docs.victoriametrics.com/vmagent.html#automatically-generated-metrics for more details.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5074
2023-10-02 20:59:56 +02:00
Roman Khavronenko
74301cdbf5
lib/promscrape: add metric vm_promscrape_scrapes_skipped_total (#5074)
* lib/promscrape: add metric `vm_promscrape_scrapes_skipped_total`

add metric `vm_promscrape_scrapes_skipped_total`to show whether vmagent skips the scrapes.
This could happen if vmagent is overloaded or target is responding too slow for configured `scrape_interval`.

The follow-up commit should add a corresponding alerting rule and panel to vmagent dashboard.

Signed-off-by: hagen1778 <roman@victoriametrics.com>

* deployment/docker: add `TooManyScrapeSkips` alerting rule for vmagent

Signed-off-by: hagen1778 <roman@victoriametrics.com>

* dashboards: add panels `Scrape duration 0.99 quantile` and `Skipped scrapes` to vmagent dashboard

Signed-off-by: hagen1778 <roman@victoriametrics.com>

---------

Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-10-02 17:12:12 +02:00
Zakhar Bessarab
8d99c12a7d
lib/promscrape/discovery/kubernetes: supress context.Cancelled error in logs (#5048)
lib/promscrape/discovery/kubernetes: supress context.Cancelled error in logs

It is possible that context.Cancelled will appear after k8s watcher was closed due to reload(see https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4850).

Logging an error misinforms user and looks like vmagent discovery will stop working even though this does not affect discovery.

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
2023-09-22 13:01:33 +02:00
Aliaksandr Valialkin
30a645cd82
lib/promscrape/discovery/kubernetes: follow-up after 03fece44e0
- Properly update vm_promscrape_discovery_kubernetes_url_watchers
  and vm_promscrape_discovery_kubernetes_group_watchers metrics after config changes

- Properly stop goroutine responsible for recreating scrapeWorks after the corresponding urlWatcher is stopped

- Log the event when urlWatcher is stopped in order to simplify debugging

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4850
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4861
2023-09-18 23:23:45 +02:00
Aliaksandr Valialkin
03fece44e0
lib/promscrape/discovery/kubernetes: wait for 10 seconds before checking whether the urlWatcher must be stopped
This should prevent from excess urlWatcher churn on config reload, since it leads to removal of all the apiWatchers
before creating new apiWatchers. So, every config reload would lead to stopping of all the previous urlWatchers
and starting new urlWatchers.

The new logic gives 10 seconds for config reload before stopping unused urlWatchers.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4850
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4861
2023-09-18 17:45:12 +02:00
Aliaksandr Valialkin
76af32d869
lib/promscrape/discovery/kubernetes: follow-up after eeb862f3ff
- Move the bugfix description to the correct place in docs/CHANGELOG.md
- Prevent from logging of 'context canceled' errors after the url watcher is stopped,
  since these errors are expected and may confuse users.
- Remove unused urlWatcher.refCount field.
- Remove unused urlWatcher.close() method.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4850
2023-09-18 17:06:39 +02:00
Zakhar Bessarab
eeb862f3ff
lib/promscrape/discovery/kubernetes: fix leaking api watcher (#4861)
* lib/promscrape/discovery/kubernetes: fix leaking api watcher

goroutine which was polling k8s API had no execution control. This leaded to leaking goroutines during config reload.

See: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4850
Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

* lib/promscrape/discovery/kubernetes: use reference counting for urlWatcher cleanup

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

* lib/promscrape/discovery/kubernetes: remove waitgroup sync for goroutines polling API server

This is unnecessary since context will is cancelled and new requests will not be sent. Also, using waitgroup will increase time required to perform reload which might result in missed scrapes.

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

* lib/promscrape/discovery/kubernetes: clarify comment

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

* Apply suggestions from code review

* lib/promscrape/discovery/kubernetes: address review feedback

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>
2023-09-15 19:40:13 +02:00
Aliaksandr Valialkin
edee262ecc
Makefile: update golangci-lint from v1.51.2 to v1.54.2
See https://github.com/golangci/golangci-lint/releases/tag/v1.54.2
2023-09-01 10:16:42 +02:00
Nikolay
00685b627f
lib/promscrape/k8s_sd: set resourceVersion to 0 by default for watch … (#4901)
* lib/promscrape/k8s_sd: set resourceVersion to 0 by default for watch requests
it must reduce load for kubernetes ETCD servers. Since requests without resourceVersion performs force cache sync at kubernetes API server with ETCD
more info at https://kubernetes.io/docs/reference/using-api/api-concepts/\#semantics-for-watch
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4855

* wip

---------

Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
2023-08-30 16:03:41 +02:00
hagen1778
5d848363f0
lib/promscrape: follow-up after eabcfc9bcd
`-promscrape.cluster.membersCount` by default should be `1`, like every
single vmagent is a cluster of one member on its own.
The change additionally validates that user can't set `-promscrape.cluster.membersCount`
to value lower than `1`.

eabcfc9bcd
Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-08-29 10:04:57 +02:00
Haleygo
eabcfc9bcd
fix clusterMembersCount check (#4900) 2023-08-29 15:58:24 +08:00
Zakhar Bessarab
6e8611f301
lib/promscrape/client: sync timeout for HostClient and http.Client (#4889)
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>
2023-08-25 15:47:11 +02:00
Aliaksandr Valialkin
f1c2508243
lib/promscrape: add -promscrape.cluster.memberLabel command-line flag
This flag allows specifying an additional label to add to all the scraped metrics.
The flag must contain label name to add. The label value will be equal to -promscrape.cluster.memberNum.

This functionality can help when there is a need to differentiate metrics scraped
by distinct vmagent instances in the cluster according to https://docs.victoriametrics.com/vmagent.html#scraping-big-number-of-targets

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4247

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4247#issuecomment-1692279393
2023-08-24 22:03:54 +02:00
hagen1778
4ebe8bb1d5
app/vmagent: follow-up after 6788704152
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4884
Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-08-24 11:36:42 +02:00
Zakhar Bessarab
6788704152
lib/promscrape/client: make User-Agent consistent between fasthttp and native client (#4886)
User agent was not set for native client which resulted in using one provided by Golang.

See: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4884

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
2023-08-24 11:31:13 +02:00
Aliaksandr Valialkin
d18ff993e6
lib/promscrape: add a comment why honor_timestamps is set to false by default
This should prevent from returning it back to true in the future

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4697
2023-07-28 21:36:32 -07:00
Aliaksandr Valialkin
e3ef3df938
lib/promscrape: use local scrape timestamp for scraped metrics unless honor_timestamps: true is set explicitly
This fixes the case with gaps for metrics collected from cadvisor,
which exports invalid timestamps, which break staleness detection at VictoriaMetrics side.

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4697 ,
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4697#issuecomment-1654614799
and https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4697#issuecomment-1656540535

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/1773
2023-07-28 21:11:26 -07:00
Aliaksandr Valialkin
3d73640815
lib/promscrape/discovery: close unused HTTP connections to service discovery servers
This should prevent from connection leaks

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4724
2023-07-27 14:48:56 -07:00
Aliaksandr Valialkin
49bd2905fa
lib/promscrape: follow-up after 6aa50ca954
- Improve docs
- Hide `debug relabeling` column when -promscrape.dropOriginalLabels command-line flag is set
- Inline the code from the added template functions, since the code is harder to follow
  with the template functions, especially when these functions have misleading names.
  Also, these functions are used only in one place, e.g. they do not reduce the amounts of code.
- Hide `click to show original labels` title at `labels` column when original labels aren't available.
- Show the reason on whey original labels aren't available at /service-discovery page.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4597
2023-07-20 19:14:33 -07:00
Dmytro Kozlov
6aa50ca954
app/vmagent: fix creating target id if --promscrape.dropOriginalLabels flag was used (#4616)
* app/vmagent: fix creating target id if `--promscrape.dropOriginalLabels` flag was used

* app/vmagent: hide links if OriginalLabels was dropped

* app/vmagent: update CHANGELOG.md and added information to the docs

* app/vmagent: fix comments
2023-07-20 10:13:39 +02:00
Aliaksandr Valialkin
140e7b6b74
all: replace atomic.Value with atomic.Pointer[T]
This eliminates the need in .(*T) casting for results obtained from Load()

Leave atomic.Value for map, since atomic.Pointer[map[...]...] makes double pointer to map,
because map is already a pointer type.
2023-07-19 17:42:06 -07:00
Aliaksandr Valialkin
8a07621a0c
lib/promscrape: disable support for service discovery and metrics scrape via http2
Reasons for disabling http2:

- http2 is used very rarely comparing to http for Prometheus metrics exposition and service discovery
- http2 is much harder to debug than http
- http2 has very bad security record because of its complexity - see https://portswigger.net/research/http2

VictoriaMetrics components are compiled with nethttpomithttp2 tag because of these issues.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4283
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4274

This is a follow-up for 72c3cd47eb
2023-07-06 16:03:37 -07:00
Aliaksandr Valialkin
792860db10
lib/promscrape/discoveryutils: re-use checkRedirect function for both client and blockingClient
Also document follow_redirects option at https://docs.victoriametrics.com/sd_configs.html#http-api-client-options

This is a follow-up for b3d0ff463a

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4282
2023-07-06 10:51:33 -07:00
Alexander Marshalov
40d12be607
fixed service name detection for consulagent service discovery in case of a difference in service name and service id (#4390) (#4439)
Signed-off-by: Alexander Marshalov <_@marshalov.org>
2023-06-12 16:16:43 +02:00
Roman Khavronenko
dfe53a36fc
lib/promscrape/discoveryutils: properly check for net.ErrClosed (#4426)
This error may be wrapped in another error, and should normally be tested using
`errors.Is(err, net.ErrClosed)`.

Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-06-09 09:26:33 +02:00
Roman Khavronenko
3305a6901c
app/vmagent: mention enable_http2 in changelog (#4403)
Follow-up after
72c3cd47eb

Signed-off-by: hagen1778 <roman@victoriametrics.com>
2023-06-05 16:31:58 +02:00
Haleygo
72c3cd47eb
vmagent:scrape config support enable_http2 (#4295)
app/vmagent: support `enable_http2` in scrape config 

This change adds HTTP2 support for scrape config
and improves compatibility with Prometheus config. 

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4283
2023-06-05 15:56:49 +02:00
Haleygo
b3d0ff463a
vmagent:support follow_redirects on SD level (#4286)
* vmagent:support follow_redirects on SD level

* fix follow_redirects on sd level

https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4282
2023-05-26 09:39:45 +02:00
Alexander Marshalov
2e494e2375
fixed typos in documentation and commandline flags descriptions (#4275) 2023-05-10 09:50:41 +02:00
Aliaksandr Valialkin
b9bb64ce55
lib/promscrape/discovery/consulagent: substitute metaPrefix with the __meta_consulagent_ plaintext string
This simplifies future code navigation and search for the specific meta-label starting from __meta_consulagent_* prefix.
For example, `grep __meta_consulagent_namespace` finds the exact place where this label is defined.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3953
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/pull/4217
2023-05-08 23:40:13 -07:00
Aliaksandr Valialkin
74155afb71
docs: clarify docs after 5ee344824f
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4183
2023-05-08 16:11:44 -07:00
Aliaksandr Valialkin
ec3943d14a
app/vmselect: small cleanup after 4f3f9950d0
Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3807
2023-05-08 14:57:11 -07:00
Alexander Marshalov
8225a48b56
fixed vm_promscrape_config_last_reload_successful metric value recovery after successful reloading with unchanged content (#4260) (#4268)
Signed-off-by: Alexander Marshalov <_@marshalov.org>
2023-05-08 13:32:51 +02:00
Zakhar Bessarab
4e71003620
lib/promscrape/discovery/kubernetes: follow-up for d5e94721db (#4255)
- add changelog reference to an author
- fix tests
- add metadata to match Prometheus behavior

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
2023-05-05 14:41:17 +02:00
Vasilchenko Anton
22e65402af
Add endpoint labels for pod targets discovered form endpoint but has different ports (#4253)
Signed-off-by: Vasilchenko Anton <vasilchenko-as@yandex.ru>
2023-05-05 15:46:07 +04:00
Alexander Marshalov
56b84140a9
added new consulagent service discovery (#3953) (#4217) 2023-05-04 11:36:21 +02:00
Zakhar Bessarab
bf3b6732bd
lib/promscrape/discovery/kubernetes: add common labels to all ports discovered from endpoints (#4235)
* lib/promscrape/discovery/kubernetes: add common labels to all ports discovered from endpoints

Sets
`__meta_kubernetes_endpoints_name` and `__meta_kubernetes_namespace` labels to all ports of pod.
Prometheus sets those labels to all ports in pod (0ab9553611/discovery/kubernetes/endpoints.go (L267C15-L269)) even if port is not matching any service.

See: #4154

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

* lib/promscrape/discovery/kubernetes: fix test for updated discovery logic

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

---------

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
2023-05-03 02:17:33 +02:00
Nikolay
5ee344824f
lib/promscrape: adds filter for consul_sd_configs: (#4184)
* lib/promscrape: adds filter for consul_sd_configs:
it allows advanced filtering for consul service discovery requests
https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4183

* typo fix

* removes deprecation mentions since it's not relevant

* Update docs/CHANGELOG.md

Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>

---------

Co-authored-by: Roman Khavronenko <roman@victoriametrics.com>
2023-04-26 19:16:27 +02:00
Yury Molodov
4f3f9950d0
vmui: add metric relabel debug (#3889)
* feat: add metric relabel debug (#3807)

* fix: add link to relabeling cookbook

* lib/promrelabel: merge, fix conflicts

* lib/promrelabel: fix diff

* docs/vmui: add metric relabel playground

---------

Co-authored-by: dmitryk-dk <kozlovdmitriyy@gmail.com>
2023-04-26 11:53:29 +03:00
Aliaksandr Valialkin
f638496298
lib/promscrape: do not re-use previously loaded scrape targets on failed attempt to load updated scrape targets at file_sd_configs
The logic employed for re-using the previously loaded scrape target was broken initially.
The commit cc0427897c tried to fix it, but the new logic
became too complex and fragile. So it is better to just remove this logic,
since the targets from temporarily broken file should be eventually loaded on next
attempts every -promscrape.fileSDCheckInterval

This also allows removing fragile hacks around __vm_filepath label.

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3989
2023-04-02 21:05:28 -07:00
Dmytro Kozlov
cc0427897c
lib/promscrape: fix the problem with scrape work duplicates when file_sd_config can't be read (#4027)
* lib/promscrape: fix the problem with scrape work duplicates when file_sd_config can't be read

* lib/promscrape: clarified comment

* lib/promscrape: made better approach to handle a problem with growing []*ScrapeWork on each error when loading config

* lib/promscrape: added CHANGELOG.md

* Update docs/CHANGELOG.md

---------

Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
2023-04-02 20:26:13 -07:00
Aliaksandr Valialkin
d577657fb7
lib/streamaggr: follow-up for ff72ca14b9
- Make sure that the last successfully loaded config is used on hot-reload failure
- Properly cleanup resources occupied by already initialized aggregators
  when the current aggregator fails to be initialized
- Expose distinct vmagent_streamaggr_config_reload* metrics per each -remoteWrite.streamAggr.config
  This should simplify monitoring and debugging failed reloads
- Remove race condition at app/vminsert/common.MustStopStreamAggr when calling sa.MustStop() while sa
  could be in use at realoadSaConfig()
- Remove lib/streamaggr.aggregator.hasState global variable, since it may negatively impact scalability
  on system with big number of CPU cores at hasState.Store(true) call inside aggregator.Push().
- Remove fine-grained aggregator reload - reload all the aggregators on config change instead.
  This simplifies the code a bit. The fine-grained aggregator reload may be returned back
  if there will be demand from real users for it.
- Check -relabelConfig and -streamAggr.config files when single-node VictoriaMetrics runs with -dryRun flag
- Return back accidentally removed changelog for v1.87.4 at docs/CHANGELOG.md

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3639
2023-03-31 22:30:38 -07:00
Dmytro Kozlov
e79cd24807
lib/promrelabel: make target url from labels on target relabel page (#3882)
* lib/promrelabel: make target url from labels on target relabel page

* wip

---------

Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
2023-03-20 22:07:52 -07:00
Haleygo
d056be710b
fix some typo (#3898) 2023-03-03 11:02:13 +01:00
Zakhar Bessarab
5fadd58cf6
lib/promscrape: correctly register vm_promscrape_config_* metrics (#3876)
* lib/promscrape: set `vm_promscrape_config_last_reload_successful` to 1 if there was no promscrape config provided

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

* lib/promscrape: register `vm_promscrape_config_*` metrics only in case promscrape config is used

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>

---------

Signed-off-by: Zakhar Bessarab <z.bessarab@victoriametrics.com>
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
2023-02-27 11:53:53 -08:00
Aliaksandr Valialkin
f7ef80aaad
.golangci.yml: properly enable revive linter and fix all the warnings it detects 2023-02-26 12:18:59 -08:00
Aliaksandr Valialkin
c6ad3692ad
lib/promscrape: follow-up for 43e104a83f
- 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
2023-02-24 12:20:42 -08:00
Zakhar Bessarab
43e104a83f
fix: do not use exponential backoff for first retry of scrape request (#3824)
* 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>
2023-02-24 11:39:56 -08:00
Aliaksandr Valialkin
e688121de8
lib/promscrape/discovery/kuma: substitute blocking HTTP call with non-blocking HTTP call at discoveryutils.Client 2023-02-23 15:13:08 -08:00
Mattias Ängehov
6d019a3c37
Azure Service Discovery - Fix token fetch for Container Apps/App Services (#3832)
* Modify API version when running in Container App

* Handle expires on from token response

Response from IMDS does not always contain expires in value which is
currently used to get the token expiry time. An example resources that
doesn't provide it are Container Apps and App Service.

Signed-off-by: Mattias Ängehov <mattias.angehov@castoredc.com>

* Fix client id parameter for user assigned identity

* Apply suggestions from code review

---------

Signed-off-by: Mattias Ängehov <mattias.angehov@castoredc.com>
Co-authored-by: Aliaksandr Valialkin <valyala@gmail.com>
2023-02-22 19:19:53 -08:00
Aliaksandr Valialkin
510f78a96b
all: consistently use http.Method{Get,Post,Put} across the codebase
This is a follow-up after 9dec3c8f80
2023-02-22 18:58:46 -08:00
my-git9
9dec3c8f80
chore: Use http constants to replace numbers (#3846)
Signed-off-by: xin.li <xin.li@daocloud.io>
2023-02-22 18:53:05 -08:00
Aliaksandr Valialkin
9fbd45a22f
lib/promscrape/discovery/kuma: follow-up for 317fef95f9
- Do not generate __meta_server label, since it is unavailable in Prometheus.
- Add a link to https://docs.victoriametrics.com/sd_configs.html#kuma_sd_configs to docs/CHANGELOG.md,
  so users could click it and read the docs without the need to search the corresponding docs.
- Remove kumaTarget struct, since it is easier generating labels for discovered targets
  directly from the response returned by Kuma. This simplifies the code.
- Store the generated labels for discovered targets inside atomic.Value. This allows reading them
  from concurrent goroutines without the need to use mutex.
- Use synchronouse requests to Kuma instead of long polling, since there is a little sense
  in the long polling when the Kuma server may return 304 Not Modified response every -promscrape.kumaSDCheckInterval.
- Remove -promscrape.kuma.waitTime command-line flag, since it is no longer needed when long polling isn't used.
- Set default value for -promscrape.kumaSDCheckInterval to 30s in order to be consistent with Prometheus.
- Remove unnecessary indirections for string literals, which are used only once, in order to improve code readability.
- Remove unused fields from discoveryRequest and discoveryResponse.
- Update tests.
- Document why fetch_timeout and refresh_interval options are missing in kuma_sd_config.
- Add docs to discoveryutils.RequestCallback and discoveryutils.ResponseCallback,
  since these are public types.

Side notes: it is weird that Prometheus implementation for kuma_sd_configs sets `instance` label,
since usually this label is set by the Prometheus itself to __address__ after the relabeling phase.
See https://www.robustperception.io/life-of-a-label/

Updates https://github.com/VictoriaMetrics/VictoriaMetrics/issues/3389

See https://github.com/prometheus/prometheus/issues/7919
and https://github.com/prometheus/prometheus/pull/8844
as a reference implementation in Prometheus
2023-02-22 17:51:51 -08:00