2023-06-24 Telegraf - master branch - PR 1 of 2

[Paraphraser]

Issue reported on Discord led to the discovery of several problems with Telegraf:

1. Default configuration had been amended to:

   • Add support for both InfluxDB 1.8 and InfluxDB 2; and
   • Comment-out both InfluxDB outputs.

   The practical consequences were:

   • The Dockerfile sed command could not find [outputs.influxdb], so the urls = ["http://influxdb:8086"] could not be inserted, so telegraf could not write to any database; and
   • The container went into a restart loop.

2. The default entrypoint.sh script had been amended to invoke telegraf via:

   exec setpriv --reuid telegraf --init-groups "$@"

   Inside the container, user "telegraf" is userID 999. Outside container space, user 999 is not a member of the docker group so it doesn't have access to /var/run/docker.sock.

   The practical consequence was the telegraf process inside the container endlessly complaining:

   E! [inputs.docker] Error in plugin: permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock

Problem 1 has been addressed by removing the sed logic and adding outputs.influxdb.conf to the auto_include folder:

[[outputs.influxdb]]
urls = ["http://influxdb:8086"]

This defaults to the telegraf database and is sufficient for telegraf to get going.

Problem 2 has been addressed by not downgrading privileges. The alternative of changing the documentation to require the user to add userID 999 to the docker group is sub-optimal and not really in the spirit of IOTstack where, to the maximum extent possible, containers should "just work".