The integral accumulator in the remote write sharding code is just a
second way of keeping track of the number of samples pending. Remove
integralAccumulator and use the samplesPending value we already
calculate to calculate the number of shards.
This has the added benefit of fixing a bug where the integralAccumulator
was not being initialized correctly due to not taking into account the
number of ticks being counted, causing the integralAccumulator initial
value to be off by an order of magnitude in some cases.
Signed-off-by: Chris Marchbanks <csmarchbanks@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>
* Refactor calculateDesiredShards + don't reshard if we're having issues
sending samples.
* Track lastSendTimestamp via an int64 with atomic add/load, add a test
for reshard calculation.
* Simplify conditional for skipping resharding, add samplesIn/Out to shard
testcase struct.
Signed-off-by: Callum Styan <callumstyan@gmail.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>
* Add benchmark for sample delivery
* Simplify StoreSeries to have only one loop
* Reduce allocations for pending samples in runShard
* Only allocate one send slice per segment
* Cache a buffer in each shard for snappy to use
* Remove queue manager seriesMtx
It is not possible for any of the places protected by the seriesMtx to
be called concurrently so it is safe to remove. By removing the mutex we
can simplify the Append code to one loop.
Signed-off-by: Chris Marchbanks <csmarchbanks@gmail.com>
* Don't panic if we try to release a string that is not in the interner.
* Move seriesMtx locking in QueueManager's StoreSeries function.
This stops us from calling release for strings that aren't interned if
there's a race between reading a checkpoint and storing new series
labels, which could happen during checkpointing or reloading config.
Signed-off-by: Callum Styan <callumstyan@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>
- Remove prometheus_remote_queue_last_send_timestamp_seconds metric. Its not particularly useful, we have highest_timestamp_seconds.
- Factor out maxGauage, a gauge that only increases.
- Change sharding calculations to use max samples in timestamp - max samples out timestamp (not rates).
- Also include the ratio of samples dropped to correctly predict number of pending samples.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
- Add a dropped samples EWMA and use it in calculating desired shards.
- Update metric names and a log messages.
- Limit number of entries in the dedupe logging middleware to prevent potential OOM.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
- If we're replaying the WAL to get series records, skip that segment when we hit corruptions.
- If we're tailing the WAL for samples, fail the watcher.
- When the watcher fails, restart from the latest checkpoint - and only send new samples by updating startTime.
- Tidy up log lines and error handling, don't return so many errors on quiting.
- Expect EOF when processing checkpoints.
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
- Tests that created a QueueManager were leaving behind files at the end of tests.
- WAL replaying (readToEnd)tests seem to require extra time to finish now.
- Some fixes to make staticcheck happy
Signed-off-by: Callum Styan <callumstyan@gmail.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>
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.
* 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.
By splitting the single queue into multiple queues and flushing each individual queue in serially (and all queues in parallel), we can guarantee to preserve the order of timestampsin samples sent to downstream systems.
Specifically, the TestSpawnNotMoreThanMaxConcurrentSendsGoroutines was failing on a fresh checkout of master.
The test had a race condition -- it would only pass if one of the
spawned goroutines happened to very quickly pull a set of samples off an
internal queue.
This patch rewrites the test so that it deterministically waits until
all samples have been pulled off that queue. In case of errors, it also
now reports on the difference between what it expected and what it found.
I verified that, if the code under test is deliberately broken, the test
successfully reports on that.
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.
- 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.
Prometheus needs long-term storage. Since we don't have enough resources
to build our own timeseries storage from scratch ontop of Riak,
Cassandra or a similar distributed datastore at the moment, we're
planning on using OpenTSDB as long-term storage for Prometheus. It's
data model is roughly compatible with that of Prometheus, with some
caveats.
As a first step, this adds write-only replication from Prometheus to
OpenTSDB, with the following things worth noting:
1)
I tried to keep the integration lightweight, meaning that anything
related to OpenTSDB is isolated to its own package and only main knows
about it (essentially it tees all samples to both the existing storage
and TSDB). It's not touching the existing TieredStorage at all to avoid
more complexity in that area. This might change in the future,
especially if we decide to implement a read path for OpenTSDB through
Prometheus as well.
2)
Backpressure while sending to OpenTSDB is handled by simply dropping
samples on the floor when the in-memory queue of samples destined for
OpenTSDB runs full. Prometheus also only attempts to send samples once,
rather than implementing a complex retry algorithm. Thus, replication to
OpenTSDB is best-effort for now. If needed, this may be extended in the
future.
3)
Samples are sent in batches of limited size to OpenTSDB. The optimal
batch size, timeout parameters, etc. may need to be adjusted in the
future.
4)
OpenTSDB has different rules for legal characters in tag (label) values.
While Prometheus allows any characters in label values, OpenTSDB limits
them to a to z, A to Z, 0 to 9, -, _, . and /. Currently any illegal
characters in Prometheus label values are simply replaced by an
underscore. Especially when integrating OpenTSDB with the read path in
Prometheus, we'll need to reconsider this: either we'll need to
introduce the same limitations for Prometheus labels or escape/encode
illegal characters in OpenTSDB in such a way that they are fully
decodable again when reading through Prometheus, so that corresponding
timeseries in both systems match in their labelsets.
Change-Id: I8394c9c55dbac3946a0fa497f566d5e6e2d600b5
Robert Fratto