04ccf84559
Rationale: The default value for GOGC is 100, i.e. a garbage collected is initialized once as many heap space has been allocated as was in use after the last GC was done. This ratio doesn't make a lot of sense in Prometheus, as typically about 60% of the heap is allocated for long-lived memory chunks (most of which are around for many hours if not days). Thus, short-lived heap objects are accumulated for quite some time until they finally match the large amount of memory used by bulk memory chunks and a gigantic GC cyle is invoked. With GOGC=40, we are essentially reinstating "normal" GC behavior by acknowledging that about 60% of the heap are used for long-term bulk storage. The median Prometheus production server at SoundCloud runs a GC cycle every 90 seconds. With GOGC=40, a GC cycle is run every 35 seconds (which is still not very often). However, the effective RAM usage is now reduced by about 30%. If settings are updated to utilize more RAM, the time between GC cycles goes up again (as the heap size is larger with more long-lived memory chunks, but the frequency of creating short-lived heap objects does not change). On a quite busy large Prometheus server, the timing changed from one GC run every 20s to one GC run every 12s. In the former case (just changing GOGC, leave everything else as it is), the CPU usage increases by about 10% (on a mid-size referenc server from 8.1 to 8.9). If settings are adjusted, the CPU consumptions increases more drastically (from 8 cores to 13 cores on a large reference server), despite GCs happening more rarely, presumably because a 50% larger set of memory chunks is managed now. Having more memory chunks is good in many regards, and most servers are running out of memory long before they run out of CPU cycles, so the tradeoff is overwhelmingly positive in most cases. Power users can still set the GOGC environment variable as usual, as the implementation in this commit honors an explicitly set variable. |
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|---|---|---|
| .github | ||
| cmd | ||
| config | ||
| console_libraries | ||
| consoles | ||
| discovery | ||
| documentation | ||
| notifier | ||
| promql | ||
| relabel | ||
| retrieval | ||
| rules | ||
| scripts | ||
| storage | ||
| template | ||
| util | ||
| vendor | ||
| web | ||
| .codeclimate.yml | ||
| .dockerignore | ||
| .gitignore | ||
| .promu.yml | ||
| .travis.yml | ||
| CHANGELOG.md | ||
| circle.yml | ||
| code-of-conduct.md | ||
| CONTRIBUTING.md | ||
| Dockerfile | ||
| LICENSE | ||
| MAINTAINERS.md | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| VERSION | ||
Prometheus 
Visit prometheus.io for the full documentation, examples and guides.
Prometheus, a Cloud Native Computing Foundation project, is a systems and service monitoring system. It collects metrics from configured targets at given intervals, evaluates rule expressions, displays the results, and can trigger alerts if some condition is observed to be true.
Prometheus' main distinguishing features as compared to other monitoring systems are:
- a multi-dimensional data model (timeseries defined by metric name and set of key/value dimensions)
- a flexible query language to leverage this dimensionality
- no dependency on distributed storage; single server nodes are autonomous
- timeseries collection happens via a pull model over HTTP
- pushing timeseries is supported via an intermediary gateway
- targets are discovered via service discovery or static configuration
- multiple modes of graphing and dashboarding support
- support for hierarchical and horizontal federation
Architecture overview
Install
There are various ways of installing Prometheus.
Precompiled binaries
Precompiled binaries for released versions are available in the download section on prometheus.io. Using the latest production release binary is the recommended way of installing Prometheus. See the Installing chapter in the documentation for all the details.
Debian packages are available.
Docker images
Docker images are available on Quay.io.
You can launch a Prometheus container for trying it out with
$ docker run --name prometheus -d -p 127.0.0.1:9090:9090 quay.io/prometheus/prometheus
Prometheus will now be reachable at http://localhost:9090/.
Building from source
To build Prometheus from the source code yourself you need to have a working Go environment with version 1.5 or greater installed.
You can directly use the go tool to download and install the prometheus
and promtool binaries into your GOPATH. We use Go 1.5's experimental
vendoring feature, so you will also need to set the GO15VENDOREXPERIMENT=1
environment variable in this case:
$ GO15VENDOREXPERIMENT=1 go get github.com/prometheus/prometheus/cmd/...
$ prometheus -config.file=your_config.yml
You can also clone the repository yourself and build using make:
$ mkdir -p $GOPATH/src/github.com/prometheus
$ cd $GOPATH/src/github.com/prometheus
$ git clone https://github.com/prometheus/prometheus.git
$ cd prometheus
$ make build
$ ./prometheus -config.file=your_config.yml
The Makefile provides several targets:
- build: build the
prometheusandpromtoolbinaries - test: run the tests
- format: format the source code
- vet: check the source code for common errors
- assets: rebuild the static assets
- docker: build a docker container for the current
HEAD
More information
- The source code is periodically indexed: Prometheus Core.
- You will find a Travis CI configuration in
.travis.yml. - See the Community page for how to reach the Prometheus developers and users on various communication channels.
Contributing
Refer to CONTRIBUTING.md
License
Apache License 2.0, see LICENSE.