Not able to get correct number of Open File descriptor from node-exporter metrics

Question

We are using node_exporter version 0.18.0

In Grafana Node Exporter dashboards, it shows the no of open file descriptors used by the Node Exporter process only, not the FDS used by the OS in that instance.

We are running node-exporter from root user.

System Stats:

Output of lsof | wc -l is 446732

open files (-n) 400000

Node Exporter Metrics:

node_filefd_allocated 3232

node_filefd_maximum 1.508219e+06

node_scrape_collector_duration_seconds{collector="filefd"} 4.4016e-05

process_max_fds 1024

process_open_fds 9

Answer 1

node_filefd_allocated is the metric you want.

Not everything that is listed by lsof uses a file descriptor on Linux, such as dynamically linked libraries.

We are running node-exporter from root user.

The node exporter does not require root.