To evenly distribute scraping load we currently rely on random
jittering. This commit hashes over the target's identity and calculates
a consistent offset. This also ensures that scrape intervals
are constantly spaced between config/target changes.
This gives up on the idea to communicate throuh the Append() call (by
either not returning as it is now or returning an error as
suggested/explored elsewhere). Here I have added a Throttled() call,
which has the advantage that it can be called before a whole _batch_
of Append()'s. Scrapes will happen completely or not at all. Same for
rule group evaluations. That's a highly desired behavior (as discussed
elsewhere). The code is even simpler now as the whole ingestion buffer
could be removed.
Logging of throttled mode has been streamlined and will create at most
one message per minute.
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).
Bump timeouts of tests where we don't want I/O timeouts.
Adjust the full channel test to be much more reliable,
by reducing the ingestion timeout from 1ms to 0.
Allow scrape_configs to have an optional proxy_url option which specifies
a proxy to be used for all connections to hosts in that config.
Internally this modifies the various client functions to take a *url.URL pointer
which currently must point to an HTTP proxy (but has been left open-ended to
allow the url format to be extended to support others, such as maybe SOCKS if
needed).
This commit adds the honor_labels and params arguments to the scrape
config. This allows to specify query parameters used by the scrapers
and handling scraped labels with precedence.
The main purpose of this is to allow for blacklisting
of expensive metrics as a tactical option.
It could also find uses for renaming and removing labels
from federation.
The main purpose of this is to allow for blacklisting
of expensive metrics as a tactical option.
It could also find uses for renaming and removing labels
from federation.
Appending to the storage can block for a long time. Timing out
scrapes can also cause longer blocks. This commit avoids that those
blocks affect other compnents than the target itself.
Also the Target interface was removed.
The target implementation and interface contain methods only serving a
specific purpose of the templates. They were moved to the template
as they operate on more fundamental target data.
This commits adds file based service discovery which reads target
groups from specified files. It detects changes based on file watches
and regular refreshes.
This commit changes the configuration interface from job configs to scrape
configs. This includes allowing multiple ways of target definition at once
and moving DNS SD to its own config message. DNS SD can now contain multiple
DNS names per configured discovery.
This commit shifts responsibility for maintaining targets from providers and
pools to the target manager. Target groups have a source name that identifies
them for updates.
/api/targets was undocumented and never used and also broken.
Showing instance and job labels on the status page (next to targets)
does not make sense as those labels are set in an obvious way.
Also add a doc comment to TargetStateToClass.
The one central sample ingestion channel has caused a variety of
trouble. This commit removes it. Targets and rule evaluation call an
Append method directly now. To incorporate multiple storage backends
(like OpenTSDB), storage.Tee forks the Append into two different
appenders.
Note that the tsdb queue manager had its own queue anyway. It was a
queue after a queue... Much queue, so overhead...
Targets have their own little buffer (implemented as a channel) to
avoid stalling during an http scrape. But a new scrape will only be
started once the old one is fully ingested.
The contraption of three pipelined ingesters was removed. A Target is
an ingester itself now. Despite more logic in Target, things should be
less confusing now.
Also, remove lint and vet warnings in ast.go.
The current wording suggests that a target is not reachable at all,
although it might also get set when the target was reachable, but there
was some other error during the scrape (invalid headers or invalid
scrape content). UNHEALTHY is a more general wording that includes all
these cases.
For consistency, ALIVE is also renamed to HEALTHY.
This is now not even trying to throttle in a benign way, but creates a
fully-fledged error. Advantage: It shows up very visible on the status
page. Disadvantage: The server does not really adjusts to a lower
scraping rate. However, if your ingestion backs up, you are in a very
irregulare state, I'd say it _should_ be considered an error and not
dealt with in a more graceful way.
In different news: I'll work on optimizing ingestion so that we will
not as easily run into that situation in the first place.
- Move CONTRIBUTORS.md to the more common AUTHORS.
- Added the required NOTICE file.
- Changed "Prometheus Team" to "The Prometheus Authors".
- Reverted the erroneous changes to the Apache License.
The "Address" is actually a URL which may contain username and
password. Calling this Address is misleading so we rename it.
Change-Id: I441c7ab9dfa2ceedc67cde7a47e6843a65f60511
Essentially:
- Remove unused code.
- Make it 'go vet' clean. The only remaining warnings are in generated code.
- Make it 'golint' clean. The only remaining warnings are in gerenated code.
- Smoothed out same minor things.
Change-Id: I3fe5c1fbead27b0e7a9c247fee2f5a45bc2d42c6
