Telegraf getting "protocol wrong type for socket" error while trying to connect to powerdns-recursor socket

[rumato163]

Relevant telegraf.conf

[global_tags]

[agent]
  interval                                   = "30s"
  round_interval                             = false
  metric_batch_size                          = 1000
  metric_buffer_limit                        = 10000
  collection_jitter                          = "1s"
  flush_interval                             = "30s"
  flush_jitter                               = "0s"
  precision                                  = ""
  debug                                      = false
  quiet                                      = false
  logfile                                    = "/var/log/telegraf/telegraf_pdns.log"
  omit_hostname                              = true

[[inputs.powerdns_recursor]]
  unix_sockets = ["/var/run/pdns-recursor/pdns_recursor.controlsocket"]
  socket_dir = "/var/run/pdns-recursor"

Logs from Telegraf

2022-11-16T18:06:30Z E! [inputs.powerdns_recursor] Error in plugin: dial unixgram /var/run/pdns-recursor/pdns_recursor_telegraf5655722885986422923->/var/run/pdns-recursor/pdns_recursor.controlsocket: connect: protocol wrong type for socket
2022-11-16T18:06:59Z E! [inputs.powerdns_recursor] Error in plugin: dial unixgram /var/run/pdns-recursor/pdns_recursor_telegraf7462219148622404987->/var/run/pdns-recursor/pdns_recursor.controlsocket: connect: protocol wrong type for socket
2022-11-16T18:07:29Z E! [inputs.powerdns_recursor] Error in plugin: dial unixgram /var/run/pdns-recursor/pdns_recursor_telegraf8389597005953665423->/var/run/pdns-recursor/pdns_recursor.controlsocket: connect: protocol wrong type for socket
2022-11-16T18:07:59Z E! [inputs.powerdns_recursor] Error in plugin: dial unixgram /var/run/pdns-recursor/pdns_recursor_telegraf7230448861768785540->/var/run/pdns-recursor/pdns_recursor.controlsocket: connect: protocol wrong type for socket

System info

gentoo Linux 5.15.26-gentoo

Docker

No response

Steps to reproduce

1. Install powerdns-recursor >=4.5.X version and run it with all the necessary steps to grant telegraf user access rights to socket directory and socket itself
2. Install telegraf
3. Configure inputs.powerdns-recursor plugin as it show in README
4. Try to get metrics with telegraf
5. Get "connect: protocol wrong type for socket" error

Expected behavior

Be able to get all necessary metrics listed in README

Actual behavior

Getting "connect: protocol wrong type for socket" error instead

Additional info

No response

[powersj]

I can reproduce using a Ubuntu 22.04 LTS LXD:

2022-11-16T19:11:37Z E! [inputs.powerdns_recursor] Error in plugin: dial unixgram /var/run/pdns-recursor/pdns_recursor_telegraf5246241964455496166->/var/run/pdns-recursor/pdns_recursor.controlsocket: connect: protocol wrong type for socket

It looks like we need #9633 to land due to a changes in pdns.

next steps: review that PR and see what needs to happen to wrap it up