Limit node-exporter scope, deprecated collectors

This commit is contained in:
Johannes 'fish' Ziemke 2016-12-22 17:38:25 +01:00
parent 269ee7a7b4
commit 3db2f442ae
6 changed files with 44 additions and 12 deletions

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@ -16,3 +16,26 @@ Prometheus uses GitHub to manage reviews of pull requests.
and the _Formatting and style_ section of Peter Bourgon's [Go: Best
Practices for Production
Environments](http://peter.bourgon.org/go-in-production/#formatting-and-style).
## Collector Implementation Guidelines
The Node Exporter is not a general monitoring agent. Its sole purpose is to
expose machine metrics, as oppose to service metrics, with the only exception
being the textfile collector.
The metrics should not get transformed in a way that is hardware specific and
would require maintaining any form of vendor based mappings or conditions. If
for example a proc file contains the magic number 42 as some identifier, the
Node Exporter should expose it as it is and not keep a mapping in code to make
this human readable. Instead, the textfile collector can be used to add a static
metric which can be joined with the metrics exposed by the exporter to get human
readable identifier.
A Collector may only read `/proc` or `/sys` files, use system calls or local
sockets to retrieve metrics. It may not require root privileges. Running
external commands is not allowed for performance and reliability reasons. Use a
dedicated exporter instead or gather the metrics via the textfile collector.
The Node Exporter tries to support the most common machine metrics. For more
exotic metrics, use the textfile collector or a dedicated Exporter.

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@ -4,8 +4,8 @@
[![Docker Repository on Quay](https://quay.io/repository/prometheus/node-exporter/status)][quay]
[![Docker Pulls](https://img.shields.io/docker/pulls/prom/node-exporter.svg?maxAge=604800)][hub]
Prometheus exporter for machine metrics, written in Go with pluggable metric
collectors.
Prometheus exporter for hardware and OS metrics exposed by the kernel, written
in Go with pluggable metric collectors.
## Collectors
@ -43,21 +43,28 @@ Name | Description | OS
bonding | Exposes the number of configured and active slaves of Linux bonding interfaces. | Linux
devstat | Exposes device statistics | Dragonfly, FreeBSD
drbd | Exposes Distributed Replicated Block Device statistics | Linux
gmond | Exposes statistics from Ganglia. | _any_
interrupts | Exposes detailed interrupts statistics. | Linux, OpenBSD
ipvs | Exposes IPVS status from `/proc/net/ip_vs` and stats from `/proc/net/ip_vs_stats`. | Linux
ksmd | Exposes kernel and system statistics from `/sys/kernel/mm/ksm`. | Linux
logind | Exposes session counts from [logind](http://www.freedesktop.org/wiki/Software/systemd/logind/). | Linux
megacli | Exposes RAID statistics from MegaCLI. | Linux
meminfo_numa | Exposes memory statistics from `/proc/meminfo_numa`. | Linux
meminfo\_numa | Exposes memory statistics from `/proc/meminfo_numa`. | Linux
mountstats | Exposes filesystem statistics from `/proc/self/mountstats`. Exposes detailed NFS client statistics. | Linux
nfs | Exposes NFS client statistics from `/proc/net/rpc/nfs`. This is the same information as `nfsstat -c`. | Linux
ntp | Exposes time drift from an NTP server. | _any_
runit | Exposes service status from [runit](http://smarden.org/runit/). | _any_
supervisord | Exposes service status from [supervisord](http://supervisord.org/). | _any_
systemd | Exposes service and system status from [systemd](http://www.freedesktop.org/wiki/Software/systemd/). | Linux
tcpstat | Exposes TCP connection status information from `/proc/net/tcp` and `/proc/net/tcp6`. (Warning: the current version has potential performance issues in high load situations.) | Linux
### Deprecated
*These collectors will be (re)moved in the future.*
Name | Description | OS
---------|-------------|----
gmond | Exposes statistics from Ganglia. | _any_
megacli | Exposes RAID statistics from MegaCLI. | Linux
ntp | Exposes time drift from an NTP server. | _any_
### Textfile Collector
The textfile collector is similar to the [Pushgateway](https://github.com/prometheus/pushgateway),

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@ -16,20 +16,19 @@ package collector
import (
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
)
const Namespace = "node"
var Factories = make(map[string]func() (Collector, error))
func warnDeprecated(collector string) {
log.Warnf("The %s collector is deprecated and will be removed in the future!", collector)
}
// Interface a collector has to implement.
type Collector interface {
// Get new metrics and expose them via prometheus registry.
Update(ch chan<- prometheus.Metric) (err error)
}
// TODO: Instead of periodically call Update, a Collector could be implemented
// as a real prometheus.Collector that only gathers metrics when
// scraped. (However, for metric gathering that takes very long, it might
// actually be better to do them proactively before scraping to minimize scrape
// time.)

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@ -48,6 +48,7 @@ var illegalCharsRE = regexp.MustCompile(`[^a-zA-Z0-9_]`)
// Takes a prometheus registry and returns a new Collector scraping ganglia.
func NewGmondCollector() (Collector, error) {
warnDeprecated("gmond")
c := gmondCollector{
metrics: map[string]*prometheus.GaugeVec{},
}

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@ -50,6 +50,7 @@ func init() {
// Takes a prometheus registry and returns a new Collector exposing
// RAID status through megacli.
func NewMegaCliCollector() (Collector, error) {
warnDeprecated("megacli")
return &megaCliCollector{
cli: *megacliCommand,
driveTemperature: prometheus.NewGaugeVec(prometheus.GaugeOpts{

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@ -41,6 +41,7 @@ func init() {
// Takes a prometheus registry and returns a new Collector exposing
// the offset between ntp and the current system time.
func NewNtpCollector() (Collector, error) {
warnDeprecated("ntp")
if *ntpServer == "" {
return nil, fmt.Errorf("no NTP server specified, see -collector.ntp.server")
}