Logs are full of Unable to send command: Invalid argument

[shonfeder]

Looking at journalctl on prod shows the logs just completely clobbered with this message:

May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:58 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument

I'm not familiar, but judging from ipmitool/ipmitool#195 this may indicate a problem with our use of ipmitool, which I guess we are using for prometheus, based on this log segment:

May 03 03:05:59 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:59 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:59 opam.ci.ocaml.org sh[92734]: Unable to send command: Invalid argument
May 03 03:05:59 opam.ci.ocaml.org systemd[1]: prometheus-node-exporter-ipmitool-sensor.service: Deactivated successfully.
May 03 03:05:59 opam.ci.ocaml.org systemd[1]: Finished Collect ipmitool sensor metrics for prometheus-node-exporter.
May 03 03:06:56 opam.ci.ocaml.org systemd[1]: Starting Collect ipmitool sensor metrics for prometheus-node-exporter...
May 03 03:06:56 opam.ci.ocaml.org systemd[1]: Starting Collect apt metrics for prometheus-node-exporter...
May 03 03:06:56 opam.ci.ocaml.org systemd[1]: Starting Collect SMART metrics for prometheus-node-exporter...
May 03 03:06:57 opam.ci.ocaml.org systemd[1]: prometheus-node-exporter-smartmon.service: Deactivated successfully.
May 03 03:06:57 opam.ci.ocaml.org systemd[1]: Finished Collect SMART metrics for prometheus-node-exporter.
May 03 03:06:57 opam.ci.ocaml.org systemd[1]: prometheus-node-exporter-smartmon.service: Consumed 1.296s CPU time.

This seems to be persistent at least since May.

See also ipmitool/ipmitool#85
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