* Write exemplars to the WAL and send them over remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Update example for exemplars, print data in a more obvious format.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add metrics for remote write of exemplars.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Fix incorrect slices passed to send in remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* We need to unregister the new metrics.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Order of exemplar append vs write exemplar to WAL needs to change.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Several fixes to prevent sending uninitialized or incorrect samples with an exemplar. Fix dropping exemplar for missing series. Add tests for queue_manager sending exemplars
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Store both samples and exemplars in the same timeseries buffer to remove the alloc when building final request, keep sub-slices in separate buffers for re-use
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Condense sample/exemplar delivery tests to parameterized sub-tests
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Rename test methods for clarity now that they also handle exemplars
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Rename counter variable. Fix instances where metrics were not updated correctly
Signed-off-by: Martin Disibio <mdisibio@gmail.com>
* Add exemplars to LoadWAL benchmark
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* last exemplars timestamp metric needs to convert value to seconds with
ms precision
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Process exemplar records in a separate go routine when loading the WAL.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments related to clarifying comments and variable
names. Also refactor sample/exemplar to enqueue prompb types.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Regenerate types proto with comments, update protoc version again.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Put remote write of exemplars behind a feature flag.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address some of Ganesh's review comments.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Move exemplar remote write feature flag to a config file field.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address Bartek's review comments.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Don't allocate exemplar buffers in queue_manager if we're not going to
send exemplars over remote write.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add ValidateExemplar function, validate exemplars when appending to head
and log them all to WAL before adding them to exemplar storage.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address more reivew comments from Ganesh.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Add exemplar total label length check.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address a few last review comments
Signed-off-by: Callum Styan <callumstyan@gmail.com>
Co-authored-by: Martin Disibio <mdisibio@gmail.com>
* scrape: add label limits per scrape
Add three new limits to the scrape configuration to provide some
mechanism to defend against unbound number of labels and excessive
label lengths. If any of these limits are broken by a sample from a
scrape, the whole scrape will fail. For all of these configuration
options, a zero value means no limit.
The `label_limit` configuration will provide a mechanism to bound the
number of labels per-scrape of a certain sample to a user defined limit.
This limit will be tested against the sample labels plus the discovery
labels, but it will exclude the __name__ from the count since it is a
mandatory Prometheus label to which applying constraints isn't
meaningful.
The `label_name_length_limit` and `label_value_length_limit` will
prevent having labels of excessive lengths. These limits also skip the
__name__ label for the same reasons as the `label_limit` option and will
also make the scrape fail if any sample has a label name/value length
that exceed the predefined limits.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
* scrape: add metrics and alert to label limits
Add three gauge, one for each label limit to easily access the
limit set by a certain scrape target.
Also add a counter to count the number of targets that exceeded the
label limits and thus were dropped. This is useful for the
`PrometheusLabelLimitHit` alert that will notify the users that scraping
some targets failed because they had samples exceeding the label limits
defined in the scrape configuration.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
* scrape: apply label limits to __name__ label
Apply limits to the __name__ label that was previously skipped and
truncate the label names and values in the error messages as they can be
very very long.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
* scrape: remove label limits gauges and refactor
Remove `prometheus_target_scrape_pool_label_limit`,
`prometheus_target_scrape_pool_label_name_length_limit`, and
`prometheus_target_scrape_pool_label_value_length_limit` as they are not
really useful since we don't have the information on the labels in it.
Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
The merge of 8761 did not catch that the secrets were off by one
because it was not rebased on top of 8693.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
This makes it clear that the dockerswarm package does more than docker
swarm, but does also docker.
I have picked moby as it is the upstream name: https://mobyproject.org/
There is no user-facing change, except in the case of a bad
configuration. Previously, a user who would have a bad docker sd config
would see an error like:
> field xx not found in type dockerswarm.plain
Now that error would be turned into:
> field xx not found in type moby.plain
While not perfect, it should at not be confusing between docker and
dockerswarm.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
Prometheus adds the ability to read secrets from files. This add
this feature for the scaleway service discovery.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Contribute grafana/agent sigv4 code
* address review feedback
- move validation logic for RemoteWrite into unmarshal
- copy configuration fields from ec2 SD config
- remove enabled field, use pointer for enabling sigv4
* Update config/config.go
* Don't provide credentials if secret key / access key left blank
* Add SigV4 headers to the list of unchangeable headers.
* sigv4: don't include all headers in signature
* only test for equality in the authorization header, not the signed date
* address review feedback
1. s/httpClientConfigEnabled/httpClientConfigAuthEnabled
2. bearer_token tuples to "authorization"
3. Un-export NewSigV4RoundTripper
* add x-amz-content-sha256 to list of unchangeable headers
* Document sigv4 configuration
* add suggestion for using default AWS SDK credentials
Signed-off-by: Robert Fratto <robertfratto@gmail.com>
Co-authored-by: Julien Pivotto <roidelapluie@gmail.com>
This PR introduces support for follow_redirect, to enable users to
disable following HTTP redirects.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
Label selector can be
"set-based"(https://kubernetes.io/docs/concepts/overview/working-with-objects/labels/#set-based-requirement)
but such a selector causes Prometheus start failure with the "unexpected
error: parsing YAML file ...: invalid selector: 'foo in (bar,baz)';
can't understand 'baz)'"-like error.
This is caused by the `fields.ParseSelector(string)` function that
simply splits an expression as a CSV-list, so a comma confuses such a
parsing method and lead to the error.
Use `labels.Parse(string)` to use a valid lexer to parse a selector
expression.
Closes#8284.
Signed-off-by: Alexey Shumkin <Alex.Crezoff@gmail.com>
* Testify: move to require
Moving testify to require to fail tests early in case of errors.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* More moves
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Refactor test assertions
This pull request gets rid of assert.True where possible to use
fine-grained assertions.
Signed-off-by: Julien Pivotto <roidelapluie@inuits.eu>
* Default to bigger remote_write sends
Raise the default MaxSamplesPerSend to amortise the cost of remote
calls across more samples. Lower MaxShards to keep the expected max
memory usage within reason.
Signed-off-by: Bryan Boreham <bryan@weave.works>
* Change default Capacity to 2500
To maintain ratio with MaxSamplesPerSend
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This also fixes a bug in query_log_file, which now is relative to the config file like all other paths.
Signed-off-by: Andy Bursavich <abursavich@gmail.com>
* OpenStack SD: Add availability config option, to choose endpoint type
In some environments Prometheus must query OpenStack via an alternative
endpoint type (gophercloud calls this `availability`.
This commit implements this option.
Co-Authored-By: Dennis Kuhn <d.kuhn@syseleven.de>
Signed-off-by: Steffen Neubauer <s.neubauer@syseleven.de>
Added optional configuration item role, defaults to 'container' (backwards-compatible).
Setting role to 'cn' will discover compute nodes instead.
Human-friendly compute node hostname discovery depends on cmon 1.7.0:
c1a2aeca36
Adjust testcases to use discovery config per case as two different types are now supported.
Updated documentation:
* new role setting
* clarify what the name 'container' covers as triton uses different names in different locations
Signed-off-by: jzinkweg <jzinkweg@gmail.com>
* Track remote write queues via a map so we don't care about index.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Support a job name for remote write/read so we can differentiate between
them using the name.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Remote write/read has Name to not confuse the meaning of the field with
scrape job names.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Split queue/client label into remote_name and url labels.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Don't allow for duplicate remote write/read configs.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Ensure we restart remote write queues if the hash of their config has
not changed, but the remote name has changed.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Include name in remote read/write config hashes, simplify duplicates
check, update test accordingly.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
This change makes sure that nearly-identical Alertmanager configurations
aren't merged together.
The config's identifier was the MD5 hash of the configuration serialized
to JSON but because `relabel.Regexp` has no public field and doesn't
implement the JSON.Marshaler interface, it was always serialized to
"{}".
In practice, the identifier can be based on the index of the
configuration in the list.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
The desired shards calculation now properly keeps track of the rate of
pending samples, and uses the previously unused integralAccumulator to
adjust for missing information in the desired shards calculation.
Also, configure more capacity for each shard. The default 10 capacity
causes shards to block on each other while
sending remote requests. Default to a 500 sample capacity and explain in
the documentation that having more capacity will help throughput.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
With v0.16.0 Alertmanager introduced a new API (v2). This patch adds a
configuration option for Prometheus to send alerts to the v2 endpoint
instead of the defautl v1 endpoint.
Signed-off-by: Max Leonard Inden <IndenML@gmail.com>
i) Uses the more idiomatic Wrap and Wrapf methods for creating nested errors.
ii) Fixes some incorrect usages of fmt.Errorf where the error messages don't have any formatting directives.
iii) Does away with the use of fmt package for errors in favour of pkg/errors
Signed-off-by: tariqibrahim <tariq181290@gmail.com>
- Unmarshall external_labels config as labels.Labels, add tests.
- Convert some more uses of model.LabelSet to labels.Labels.
- Remove old relabel pkg (fixes#3647).
- Validate external label names.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
* discovery/kubernetes: fix support for password_file
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
* Create and pass custom RoundTripper to Kubernetes client
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
* Use inline HTTPClientConfig
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
This change switches the remote_write API to use the TSDB WAL. This should reduce memory usage and prevent sample loss when the remote end point is down.
We use the new LiveReader from TSDB to tail WAL segments. Logic for finding the tracking segment is included in this PR. The WAL is tailed once for each remote_write endpoint specified. Reading from the segment is based on a ticker rather than relying on fsnotify write events, which were found to be complicated and unreliable in early prototypes.
Enqueuing a sample for sending via remote_write can now block, to provide back pressure. Queues are still required to acheive parallelism and batching. We have updated the queue config based on new defaults for queue capacity and pending samples values - much smaller values are now possible. The remote_write resharding code has been updated to prevent deadlocks, and extra tests have been added for these cases.
As part of this change, we attempt to guarantee that samples are not lost; however this initial version doesn't guarantee this across Prometheus restarts or non-retryable errors from the remote end (eg 400s).
This changes also includes the following optimisations:
- only marshal the proto request once, not once per retry
- maintain a single copy of the labels for given series to reduce GC pressure
Other minor tweaks:
- only reshard if we've also successfully sent recently
- add pending samples, latest sent timestamp, WAL events processed metrics
Co-authored-by: Chris Marchbanks <csmarchbanks.com> (initial prototype)
Co-authored-by: Tom Wilkie <tom.wilkie@gmail.com> (sharding changes)
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* *: use latest release of staticcheck
It also fixes a couple of things in the code flagged by the additional
checks.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
* Use official release of staticcheck
Also run 'go list' before staticcheck to avoid failures when downloading packages.
Signed-off-by: Simon Pasquier <spasquie@redhat.com>
* discovery/azure: fail hard when client_id/client_secret is empty
Signed-off-by: mengnan <supernan1994@gmail.com>
* discovery/azure: fail hard when authentication parameters are missing
Signed-off-by: mengnan <supernan1994@gmail.com>
* add unit test
Signed-off-by: mengnan <supernan1994@gmail.com>
* add unit test
Signed-off-by: mengnan <supernan1994@gmail.com>
* format code
Signed-off-by: mengnan <supernan1994@gmail.com>
* config: set target group source index during unmarshalling
Fixes issue #4214 where the scrape pool is unnecessarily reloaded for a
config reload where the config hasn't changed. Previously, the discovery
manager changed the static config after loading which caused the in-memory
config to differ from a freshly reloaded config.
Signed-off-by: Paul Gier <pgier@redhat.com>
* [issue #4214] Test that static targets are not modified by discovery manager
Signed-off-by: Paul Gier <pgier@redhat.com>
This adds support for basic authentication which closes#3090
The support for specifying the client timeout was removed as discussed in https://github.com/prometheus/common/pull/123. Marathon was the only sd mechanism doing this and configuring the timeout is done through `Context`.
DC/OS uses a custom `Authorization` header for authenticating. This adds 2 new configuration properties to reflect this.
Existing configuration files that use the bearer token will no longer work. More work is required to make this backwards compatible.
* consul: improve consul service discovery
Related to #3711
- Add the ability to filter by tag and node-meta in an efficient way (`/catalog/services`
allow filtering by node-meta, and returns a `map[string]string` or `service`->`tags`).
Tags and nore-meta are also used in `/catalog/service` requests.
- Do not require a call to the catalog if services are specified by name. This is important
because on large cluster `/catalog/services` changes all the time.
- Add `allow_stale` configuration option to do stale reads. Non-stale
reads can be costly, even more when you are doing them to a remote
datacenter with 10k+ targets over WAN (which is common for federation).
- Add `refresh_interval` to minimize the strain on the catalog and on the
service endpoint. This is needed because of that kind of behavior from
consul: https://github.com/hashicorp/consul/issues/3712 and because a catalog
on a large cluster would basically change *all* the time. No need to discover
targets in 1sec if we scrape them every minute.
- Added plenty of unit tests.
Benchmarks
----------
```yaml
scrape_configs:
- job_name: prometheus
scrape_interval: 60s
static_configs:
- targets: ["127.0.0.1:9090"]
- job_name: "observability-by-tag"
scrape_interval: "60s"
metrics_path: "/metrics"
consul_sd_configs:
- server: consul.service.par.consul.prod.crto.in:8500
tag: marathon-user-observability # Used in After
refresh_interval: 30s # Used in After+delay
relabel_configs:
- source_labels: [__meta_consul_tags]
regex: ^(.*,)?marathon-user-observability(,.*)?$
action: keep
- job_name: "observability-by-name"
scrape_interval: "60s"
metrics_path: "/metrics"
consul_sd_configs:
- server: consul.service.par.consul.prod.crto.in:8500
services:
- observability-cerebro
- observability-portal-web
- job_name: "fake-fake-fake"
scrape_interval: "15s"
metrics_path: "/metrics"
consul_sd_configs:
- server: consul.service.par.consul.prod.crto.in:8500
services:
- fake-fake-fake
```
Note: tested with ~1200 services, ~5000 nodes.
| Resource | Empty | Before | After | After + delay |
| -------- |:-----:|:------:|:-----:|:-------------:|
|/service-discovery size|5K|85MiB|27k|27k|27k|
|`go_memstats_heap_objects`|100k|1M|120k|110k|
|`go_memstats_heap_alloc_bytes`|24MB|150MB|28MB|27MB|
|`rate(go_memstats_alloc_bytes_total[5m])`|0.2MB/s|28MB/s|2MB/s|0.3MB/s|
|`rate(process_cpu_seconds_total[5m])`|0.1%|15%|2%|0.01%|
|`process_open_fds`|16|*1236*|22|22|
|`rate(prometheus_sd_consul_rpc_duration_seconds_count{call="services"}[5m])`|~0|1|1|*0.03*|
|`rate(prometheus_sd_consul_rpc_duration_seconds_count{call="service"}[5m])`|0.1|*80*|0.5|0.5|
|`prometheus_target_sync_length_seconds{quantile="0.9",scrape_job="observability-by-tag"}`|N/A|200ms|0.2ms|0.2ms|
|Network bandwidth|~10kbps|~2.8Mbps|~1.6Mbps|~10kbps|
Filtering by tag using relabel_configs uses **100kiB and 23kiB/s per service per job** and quite a lot of CPU. Also sends and additional *1Mbps* of traffic to consul.
Being a little bit smarter about this reduces the overhead quite a lot.
Limiting the number of `/catalog/services` queries per second almost removes the overhead of service discovery.
* consul: tweak `refresh_interval` behavior
`refresh_interval` now does what is advertised in the documentation,
there won't be more that one update per `refresh_interval`. It now
defaults to 30s (which was also the current waitTime in the consul query).
This also make sure we don't wait another 30s if we already waited 29s
in the blocking call by substracting the number of elapsed seconds.
Hopefully this will do what people expect it does and will be safer
for existing consul infrastructures.
* refactor: move targetGroup struct and CheckOverflow() to their own package
* refactor: move auth and security related structs to a utility package, fix import error in utility package
* refactor: Azure SD, remove SD struct from config
* refactor: DNS SD, remove SD struct from config into dns package
* refactor: ec2 SD, move SD struct from config into the ec2 package
* refactor: file SD, move SD struct from config to file discovery package
* refactor: gce, move SD struct from config to gce discovery package
* refactor: move HTTPClientConfig and URL into util/config, fix import error in httputil
* refactor: consul, move SD struct from config into consul discovery package
* refactor: marathon, move SD struct from config into marathon discovery package
* refactor: triton, move SD struct from config to triton discovery package, fix test
* refactor: zookeeper, move SD structs from config to zookeeper discovery package
* refactor: openstack, remove SD struct from config, move into openstack discovery package
* refactor: kubernetes, move SD struct from config into kubernetes discovery package
* refactor: notifier, use targetgroup package instead of config
* refactor: tests for file, marathon, triton SD - use targetgroup package instead of config.TargetGroup
* refactor: retrieval, use targetgroup package instead of config.TargetGroup
* refactor: storage, use config util package
* refactor: discovery manager, use targetgroup package instead of config.TargetGroup
* refactor: use HTTPClient and TLS config from configUtil instead of config
* refactor: tests, use targetgroup package instead of config.TargetGroup
* refactor: fix tagetgroup.Group pointers that were removed by mistake
* refactor: openstack, kubernetes: drop prefixes
* refactor: remove import aliases forced due to vscode bug
* refactor: move main SD struct out of config into discovery/config
* refactor: rename configUtil to config_util
* refactor: rename yamlUtil to yaml_config
* refactor: kubernetes, remove prefixes
* refactor: move the TargetGroup package to discovery/
* refactor: fix order of imports
For special remote read endpoints which have only data for specific
queries, it is desired to limit the number of queries sent to the
configured remote read endpoint to reduce latency and performance
overhead.
Currently all read queries are simply pushed to remote read clients.
This is fine, except for remote storage for wich it unefficient and
make query slower even if remote read is unnecessary.
So we need instead to compare the oldest timestamp in primary/local
storage with the query range lower boundary. If the oldest timestamp
is older than the mint parameter, then there is no need for remote read.
This is an optionnal behavior per remote read client.
Signed-off-by: Thibault Chataigner <t.chataigner@criteo.com>
* k8s: Support discovery of ingresses
* Move additional labels below allocation
This makes it more obvious why the additional elements are allocated.
Also fix allocation for node where we only set a single label.
* k8s: Remove port from ingress discovery
* k8s: Add comment to ingress discovery example
This PR adds the `/status/config` endpoint which exposes the currently
loaded Prometheus config. This is the same config that is displayed on
`/config` in the UI in YAML format. The response payload looks like
such:
```
{
"status": "success",
"data": {
"yaml": <CONFIG>
}
}
```
Fixing the config/config_test, the discovery/file/file_test and the
promql/promql_test tests for Windows. For most of the tests, the fix involved
correct handling of path separators. In the case of the promql tests, the
issue was related to the removal of the temporal directories used by the
storage. The issue is that the RemoveAll() call returns an error when it
tries to remove a directory which is not empty, which seems to be true due to
some kind of process that is still running after closing the storage. To fix
it I added some retries to the remove of the temporal directories.
Adding tags file from Universal Ctags to .gitignore
* Add openstack service discovery.
* Add gophercloud code for openstack service discovery.
* first changes for juliusv comments.
* add gophercloud code for floatingip.
* Add tests to openstack sd.
* Add testify suite vendor files.
* add copyright and make changes for code climate.
* Fixed typos in provider openstack.
* Renamed tenant to project in openstack sd.
* Change type of password to Secret in openstack sd.
Allow namespace discovery to be more easily extended in the future by using a struct rather than just a list.
Rename fields for kubernetes namespace discovery
Each remote write endpoint gets its own set of relabeling rules.
This is based on the (yet-to-be-merged)
https://github.com/prometheus/prometheus/pull/2419, which removes legacy
remote write implementations.
This imposes a hard limit on the number of samples ingested from the
target. This is counted after metric relabelling, to allow dropping of
problemtic metrics.
This is intended as a very blunt tool to prevent overload due to
misbehaving targets that suddenly jump in sample count (e.g. adding
a label containing email addresses).
Add metric to track how often this happens.
Fixes#2137
Introduce two new relabel actions. labeldrop, and labelkeep.
These can be used to filter the set of labels by matching regex
- labeldrop: drops all labels that match the regex
- labelkeep: drops all labels that do not match the regex
* Add config, HTTP Basic Auth and TLS support to the generic write path.
- Move generic write path configuration to the config file
- Factor out config.TLSConfig -> tlf.Config translation
- Support TLSConfig for generic remote storage
- Rename Run to Start, and make it non-blocking.
- Dedupe code in httputil for TLS config.
- Make remote queue metrics global.
This adds `role` field to the Kubernetes SD config, which indicates
which type of Kubernetes SD should be run.
This no longer allows discovering pods and nodes with the same SD
configuration for example.
This enables defining `blackbox_exporter` targets (which can be URLs,
because of relabeling) in a JSON file.
Not sure if this is the best approach, but current behaviour is
inconsistent (`UnmarshalYAML` does not have this check) and breaks
officially documented way to use `blackbox_exporter`.
This change deprecates the `target_groups` option in favor
of `static_configs`. The old configuration is still accepted
but prints a warning.
Configuration loading errors if both options are set.
Although they are only in examples/tests and don't affect anything, they
could be confusing (the label has been renamed in the rest of the code a
while ago).
It's actually happening in several places (and for flags, we use the
standard Go time.Duration...). This at least reduces all our
home-grown parsing to one place (in model).
nerve's registration format differs from serverset. With this commit
there is now a dedicated treecache file in util,
and two separate files for serverset and nerve.
Reference:
https://github.com/airbnb/nerve
With the blackbox exporter, the instance label will commonly
be used for things other than hostnames so remove this restriction.
https://example.com or https://example.com/probe/me are some examples.
To prevent user error, check that urls aren't provided as targets
when there's no relabelling that could potentically fix them.
Usernames are not generally considered to be secrets,
and treating them as secrets may lead to confusion
as to how secure they are. Obscuring them also makes
debugging harder.
* Support multiple masters with retries against each master as required.
* Scrape masters' metrics.
* Add role meta label for node/service/master to make it easier for relabeling.
This is with `golint -min_confidence=0.5`.
I left several lint warnings untouched because they were either
incorrect or I felt it was better not to change them at the moment.
