Prometheus Node Exporter

This guide details how to set up the Prometheus Node Exporter on a Linux host. The Node Exporter collects system-level metrics and provides them in a format that Prometheus can scrape for monitoring.

Step 1: Downloading the Node Exporter

Begin by visiting the official Prometheus downloads page and selecting the Node Exporter. Choose the desired version and either download the binary directly or copy the URL for use with wget.

Once you have the URL, download the tarred file using wget. For example:

wget https://github.com/prometheus/node_exporter/releases/download/v1.3.1/node_exporter-1.3.1.linux-amd64.tar.gz

The output should resemble:

$ wget https://github.com/prometheus/node_exporter/releases/download/v1.3.1/node_exporter-1.3.1.linux-amd64.tar.gz
HTTP request sent, awaiting response... 200 OK
Length: 9033415 (8.6M) [application/octet-stream]
Saving to: ‘node_exporter-1.3.1.linux-amd64.tar.gz’

node_exporter-1.3.1.linux-amd64.tar.gz   100%[==============================================================>]   8.61M  12.4MB/s    in 0.7s

2022-09-02 15:04:10 (12.4 MB/s) - ‘node_exporter-1.3.1.linux-amd64.tar.gz’ saved [9033415/9033415]

Step 2: Extracting the Archive

Extract the downloaded tar file using the tar command:

tar -xvf node_exporter-1.3.1.linux-amd64.tar.gz

This command creates a directory named node_exporter-1.3.1.linux-amd64 containing the executable and additional files (LICENSE and NOTICE). Change to the directory with:

cd node_exporter-1.3.1.linux-amd64

Step 3: Running the Node Exporter

Inside the directory, start the Node Exporter by running its executable:

./node_exporter

You should see output indicating that the exporter is listening on the default port 9100:

ts=2022-09-05T16:51:59.947Z caller=node_exporter.go:115 level=info collector=vmstat
ts=2022-09-05T16:51:59.947Z caller=node_exporter.go:199 level=info msg="listening on" address=:9100
ts=2022-09-05T16:51:59.947Z caller=tls_config.go:195 level=info msg="TLS is disabled." http2=false

Step 4: Verifying the Installation

To confirm that the Node Exporter is running correctly, use curl to request the metrics endpoint:

curl localhost:9100/metrics

A typical response includes Prometheus-formatted metrics such as:

# TYPE promhttp_metric_handler_requests_in_flight gauge
promhttp_metric_handler_requests_in_flight 1
# HELP promhttp_metric_handler_requests_total Total number of scrapes by HTTP status code.
# TYPE promhttp_metric_handler_requests_total counter
promhttp_metric_handler_requests_total{code="200"} 0
promhttp_metric_handler_requests_total{code="500"} 0
promhttp_metric_handler_requests_total{code="503"} 0

Alternatively, open your web browser and navigate to:
http://localhost:9100/metrics

Example with a Different Version

The process remains the same if you are using a different version, such as node_exporter-1.4.0.linux-amd64. Your working directory may resemble:

user2 in ~
> ls
Desktop    Downloads    node_exporter-1.4.0.linux-amd64    Pictures    pushgateway-1.4.3.linux-amd64    snap    Videos    Documents    Music    Public    pushgateway-1.4.3.linux-amd64.tar.gz    Templates

Change into the specific directory:

cd node_exporter-1.4.0.linux-amd64

Verify the contents:

ls -la

Sample output:

total 19208
drwxr-xr-x 2 user2 user2     4096 Sep 26 08:39 .
drwxr-xr-x 17 user2 user2     4096 Nov 12 23:43 ..
-rw-r--r-- 1 user2 user2    11357 Sep 26 20:39 LICENSE
-rwxr-xr-x 1 user2 19640886 Sep 26 08:33 node_exporter
-rw-r--r-- 1 user2 user2      463 Sep 26 08:39 NOTICE

Run the exporter:

./node_exporter

Verify the metrics with:

curl localhost:9100/metrics

A sample output provides various system metrics, including CPU, memory, and network statistics:

# TYPE node_timex_tick_seconds gauge
node_timex_tick_seconds 0.01
# HELP node_udp_queues Number of allocated memory in the kernel for UDP datagrams in bytes.
# TYPE node_udp_queues gauge
node_udp_queues{ip="v4",queue="rx"} 0
node_udp_queues{ip="v4",queue="tx"} 0
node_udp_queues{ip="v6",queue="rx"} 0
node_udp_queues{ip="v6",queue="tx"} 0
# HELP node_uname_info Labeled system information as provided by the uname system call.
node_uname_info{domainname="(none)",machine="x86_64",nodename="user2",release="5.15.0-52-generic",sysname="Linux",version="#58-Ubuntu SMP Thu Oct 13 08:03:55 UTC 2022"} 1
...

Conclusion

With these steps, the Prometheus Node Exporter is now set up to collect host metrics, allowing Prometheus to scrape them from the /metrics endpoint. This installation is a key component for monitoring system performance and reliability.