Telegraf & InfluxDB: how to convert PROCSTAT's pid from field to tag? - grafana

Question

Summary: I am using telegraf to get procstat into InfluxDB. I want to convert the pid from an integer field to a TAG so that I can do group by on it in Influx.
Details:
After a lot of searching I found the following on some site but it seems to be doing the opposite (converts tag into a field). I am not sure how to deduce the opposite conversion syntax from it:
[processors]
[[processors.converter]]
namepass = [ "procstat",]
[processors.converter.tags]
string = [ "cmdline",]
I'm using Influx 1.7.9

Answer 1

The correct processor configuration to convert pid as tag is as below.
[processors]
[[processors.converter]]
namepass = [ "procstat"]
[processors.converter.fields]
tag = [ "pid"]
Please refer the documentation of converter processor plugin
https://github.com/influxdata/telegraf/tree/master/plugins/processors/converter
In the latest version of telegraf pid can be stored as tag by specifying it in the input plugin configuration. A converter processor is not needed here.
Mention pid_tag = true in the configuration. However be aware of the performance impact of having pid as a tag when processes are short lived.
P.S: You should try to upgrade your telegraf version to 1.14.5. There is a performance improvement fix for procstat plugin in this version.
Plugin configuration reference https://github.com/influxdata/telegraf/tree/master/plugins/inputs/procstat
Sample config.
# Monitor process cpu and memory usage
[[inputs.procstat]]
## PID file to monitor process
pid_file = "/var/run/nginx.pid"
## executable name (ie, pgrep <exe>)
# exe = "nginx"
## pattern as argument for pgrep (ie, pgrep -f <pattern>)
# pattern = "nginx"
## user as argument for pgrep (ie, pgrep -u <user>)
# user = "nginx"
## Systemd unit name
# systemd_unit = "nginx.service"
## CGroup name or path
# cgroup = "systemd/system.slice/nginx.service"
## Windows service name
# win_service = ""
## override for process_name
## This is optional; default is sourced from /proc/<pid>/status
# process_name = "bar"
## Field name prefix
# prefix = ""
## When true add the full cmdline as a tag.
# cmdline_tag = false
## Add the PID as a tag instead of as a field. When collecting multiple
## processes with otherwise matching tags this setting should be enabled to
## ensure each process has a unique identity.
##
## Enabling this option may result in a large number of series, especially
## when processes have a short lifetime.
# pid_tag = false