[inputs.procstat] Filter user NIS

[tguenneguez]

Relevant telegraf.conf

[[inputs.procstat]]
  pid_finder = "native"
  [[inputs.procstat.filter]]
    name = "NAMENODE"
    process_names = ["java"]
    patterns = ["org\\.apache\\.hadoop\\.hdfs\\.server\\.namenode\\.NameNode"]
    users = ["hdfs"]

Logs from Telegraf

RAS

System info

Telegraf 1.36, Red Hat Enterprise Linux Server release 7.6 (Maipo)

Docker

No response

Steps to reproduce

1. start processus with non local user
2. try to find by username with telegraf running as non root

Expected behavior

Process not found

Actual behavior

Process should be found

Additional info

Because of the use of the "id" command, which must be run by root, searching by NIS user when Telegraf is not running as root doesn't work.
https://github.com/influxdata/telegraf/blob/master/plugins/inputs/procstat/os_linux.go#L46
I'm not a Go expert, but it would be interesting to see if a Golang primitive allows the equivalent of the "id -nu " command?

[tguenneguez]

I also open an issue on golang
golang/go#75352

[tguenneguez]

This is related to the CGO_ENABLED compilation option, which is forced to 0 in the makefile.
Why is this option forced?
Is it possible to make it customizable?

[srebhan]

@tguenneguez we build our distributed binaries without CGO on most architectures as we need to link against the GLIBC of the system otherwise, rendering the resulting Telegraf binary to be distribution specific. We will not give up on this.
You can of course build your own Telegraf binary with CGO enabled.

Unfortunately, there is no API or service on Linux to read remote user information from without C... However, what I can offer is to add an option to the procstat plugin to execute id with sudo. Would this help?