This collector is based on adjtimex(2) system call. The collector returns
three values, status if time is synchronised, offset to remote reference,
and local clock frequency adjustment.
Values are taken from kernel time keeping data structures to avoid getting
involved how the synchronisation is implemented. By that I mean one should
not care if time is update using ntpd, systemd.timesyncd, ptpd, and so on.
Since all time sync implementation will always end up telling to kernel what
is the status with time one can simply omit the software in between, and
look results of the syncing. As a positive side effect this makes collector
very quick and conceptually specific, this does not monitor availability of
NTP server, or network in between, or dns resolution, and other unrelated
but necessary things.
Minimum set of values to keep eye on are the following three:
The node_timex_sync_status tells if local clock is in sync with a remote
clock. Value is set to zero when synchronisation to a reliable server
is lost, or a time sync software is misconfigured.
The node_timex_offset_seconds tells how much local clock is off when
compared to reference. In case of multiple time references this value
is outcome of RFC 5905 adjustment algorithm. Ideally offset should be
close to zero, and it depends about use case how large value is
acceptable. For example a typical web server is probably fine if offset
is about 0.1 or less, but that would not be good enough for mobile phone
base station operator.
The node_timex_freq tells amount of adjustment to local clock tick
frequency. For example if offset is one second and growing the local
clock will need instruction to tick quicker. Number value itself is not
very important, and occasional small adjustments are fine. When
frequency is unusually in stable one can assume quality of time stamps
will not be accurate to very far in sub second range. Obviously
explaining why local clock frequency behaves like a passenger in roller
coaster is different matter. Explanations can vary from system load, to
environmental issues such as a machine being physically too hot.
Rest of the measurements can help when debugging. If you run a clock server
do probably want to collect and keep track of everything.
Pull-request: https://github.com/prometheus/node_exporter/pull/664
156 lines
7.8 KiB
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156 lines
7.8 KiB
Markdown
# Node exporter [][travis]
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[][circleci]
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[](https://buildkite.com/prometheus/node-exporter)
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[][quay]
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[][hub]
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[][goreportcard]
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Prometheus exporter for hardware and OS metrics exposed by \*NIX kernels, written
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in Go with pluggable metric collectors.
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The [WMI exporter](https://github.com/martinlindhe/wmi_exporter) is recommended for Windows users.
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## Collectors
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There is varying support for collectors on each operating system. The tables
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below list all existing collectors and the supported systems.
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Which collectors are used is controlled by the `--collectors.enabled` flag.
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### Enabled by default
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Name | Description | OS
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---------|-------------|----
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arp | Exposes ARP statistics from `/proc/net/arp`. | Linux
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bcache | Exposes bcache statistics from `/sys/fs/bcache/`. | Linux
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conntrack | Shows conntrack statistics (does nothing if no `/proc/sys/net/netfilter/` present). | Linux
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cpu | Exposes CPU statistics | Darwin, Dragonfly, FreeBSD, Linux
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diskstats | Exposes disk I/O statistics. | Darwin, Linux
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edac | Exposes error detection and correction statistics. | Linux
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entropy | Exposes available entropy. | Linux
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exec | Exposes execution statistics. | Dragonfly, FreeBSD
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filefd | Exposes file descriptor statistics from `/proc/sys/fs/file-nr`. | Linux
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filesystem | Exposes filesystem statistics, such as disk space used. | Darwin, Dragonfly, FreeBSD, Linux, OpenBSD
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hwmon | Expose hardware monitoring and sensor data from `/sys/class/hwmon/`. | Linux
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infiniband | Exposes network statistics specific to InfiniBand and Intel OmniPath configurations. | Linux
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ipvs | Exposes IPVS status from `/proc/net/ip_vs` and stats from `/proc/net/ip_vs_stats`. | Linux
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loadavg | Exposes load average. | Darwin, Dragonfly, FreeBSD, Linux, NetBSD, OpenBSD, Solaris
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mdadm | Exposes statistics about devices in `/proc/mdstat` (does nothing if no `/proc/mdstat` present). | Linux
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meminfo | Exposes memory statistics. | Darwin, Dragonfly, FreeBSD, Linux
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netdev | Exposes network interface statistics such as bytes transferred. | Darwin, Dragonfly, FreeBSD, Linux, OpenBSD
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netstat | Exposes network statistics from `/proc/net/netstat`. This is the same information as `netstat -s`. | Linux
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sockstat | Exposes various statistics from `/proc/net/sockstat`. | Linux
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stat | Exposes various statistics from `/proc/stat`. This includes boot time, forks and interrupts. | Linux
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textfile | Exposes statistics read from local disk. The `--collector.textfile.directory` flag must be set. | _any_
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time | Exposes the current system time. | _any_
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timex | Exposes selected adjtimex(2) system call stats. | Linux
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uname | Exposes system information as provided by the uname system call. | Linux
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vmstat | Exposes statistics from `/proc/vmstat`. | Linux
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wifi | Exposes WiFi device and station statistics. | Linux
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xfs | Exposes XFS runtime statistics. | Linux (kernel 4.4+)
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zfs | Exposes [ZFS](http://open-zfs.org/) performance statistics. | [Linux](http://zfsonlinux.org/)
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### Disabled by default
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Name | Description | OS
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---------|-------------|----
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bonding | Exposes the number of configured and active slaves of Linux bonding interfaces. | Linux
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buddyinfo | Exposes statistics of memory fragments as reported by /proc/buddyinfo. | Linux
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devstat | Exposes device statistics | Dragonfly, FreeBSD
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drbd | Exposes Distributed Replicated Block Device statistics (to version 8.4) | Linux
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interrupts | Exposes detailed interrupts statistics. | Linux, OpenBSD
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ksmd | Exposes kernel and system statistics from `/sys/kernel/mm/ksm`. | Linux
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logind | Exposes session counts from [logind](http://www.freedesktop.org/wiki/Software/systemd/logind/). | Linux
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meminfo\_numa | Exposes memory statistics from `/proc/meminfo_numa`. | Linux
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mountstats | Exposes filesystem statistics from `/proc/self/mountstats`. Exposes detailed NFS client statistics. | Linux
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nfs | Exposes NFS client statistics from `/proc/net/rpc/nfs`. This is the same information as `nfsstat -c`. | Linux
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ntp | Exposes local NTP daemon health to check [time](./docs/TIME.md) | _any_
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qdisc | Exposes [queuing discipline](https://en.wikipedia.org/wiki/Network_scheduler#Linux_kernel) statistics | Linux
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runit | Exposes service status from [runit](http://smarden.org/runit/). | _any_
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supervisord | Exposes service status from [supervisord](http://supervisord.org/). | _any_
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systemd | Exposes service and system status from [systemd](http://www.freedesktop.org/wiki/Software/systemd/). | Linux
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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
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### Deprecated
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*These collectors will be (re)moved in the future.*
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Name | Description | OS
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---------|-------------|----
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gmond | Exposes statistics from Ganglia. | _any_
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megacli | Exposes RAID statistics from MegaCLI. | Linux
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### Textfile Collector
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The textfile collector is similar to the [Pushgateway](https://github.com/prometheus/pushgateway),
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in that it allows exporting of statistics from batch jobs. It can also be used
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to export static metrics, such as what role a machine has. The Pushgateway
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should be used for service-level metrics. The textfile module is for metrics
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that are tied to a machine.
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To use it, set the `--collector.textfile.directory` flag on the Node exporter. The
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collector will parse all files in that directory matching the glob `*.prom`
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using the [text
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format](http://prometheus.io/docs/instrumenting/exposition_formats/).
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To atomically push completion time for a cron job:
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```
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echo my_batch_job_completion_time $(date +%s) > /path/to/directory/my_batch_job.prom.$$
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mv /path/to/directory/my_batch_job.prom.$$ /path/to/directory/my_batch_job.prom
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```
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To statically set roles for a machine using labels:
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```
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echo 'role{role="application_server"} 1' > /path/to/directory/role.prom.$$
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mv /path/to/directory/role.prom.$$ /path/to/directory/role.prom
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```
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## Building and running
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go get github.com/prometheus/node_exporter
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cd ${GOPATH-$HOME/go}/src/github.com/prometheus/node_exporter
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make
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./node_exporter <flags>
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To see all available configuration flags:
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./node_exporter -h
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## Running tests
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make test
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## Using Docker
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The node\_exporter is designed to monitor the host system. It's not recommended
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to deploy it as Docker container because it requires access to the host system.
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If you need to run it on Docker, you can deploy this exporter using the
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[node-exporter Docker
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image](https://quay.io/repository/prometheus/node-exporter) with the following
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options and bind-mounts:
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```bash
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docker run -d -p 9100:9100 \
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-v "/proc:/host/proc:ro" \
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-v "/sys:/host/sys:ro" \
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-v "/:/rootfs:ro" \
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--net="host" \
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quay.io/prometheus/node-exporter \
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--collector.procfs /host/proc \
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--collector.sysfs /host/sys \
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--collector.filesystem.ignored-mount-points "^/(sys|proc|dev|host|etc)($|/)"
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```
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Be aware though that the mountpoint label in various metrics will now have
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`/rootfs` as prefix.
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## Using a third-party repository for RHEL/CentOS/Fedora
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There is a [community-supplied COPR repository](https://copr.fedorainfracloud.org/coprs/ibotty/prometheus-exporters/). It closely follows upstream releases.
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[travis]: https://travis-ci.org/prometheus/node_exporter
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[hub]: https://hub.docker.com/r/prom/node-exporter/
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[circleci]: https://circleci.com/gh/prometheus/node_exporter
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[quay]: https://quay.io/repository/prometheus/node-exporter
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[goreportcard]: https://goreportcard.com/report/github.com/prometheus/node_exporter
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