[Nut-upsdev] NUT I-D: Minimum command and variable set for conformance
roger at rogerprice.org
Mon Jan 3 11:47:18 GMT 2022
I received a comment calling for a minimum command and variable set to be
supported for conformance.
The proposal assumes that in the future there will be UPS units which natively
include an Attachment Daemon and which support direct internet access from a
Management Daemon. Something like figure 3 in section 3 of the I-D:
Such a UPS could claim to be RFC compliant, a marketing advantage, and the
comment is that such a claim should require that at least a useful subset of the
commands be implemented.
The comment proposes as the minimum set: « Battery state (charging/charged), UPS
on main power/UPS on inverter, battery percentage of charge left, and killpower
(commanding the UPS to turn itself off) at the least. »
The idea of a minimum command and variable set seems to me to be an interesting
idea, but we need to look closely as what is involved.
1. An Informational RFC cannot lay down conformance standards, but can discuss
a "Recommended minimum support for commands and variables"
2. The minimum set is for a consumer grade appliance. Professional use requires
much more to manage for example unattended servers.
To encourage discussion, I propose the following new subsection 9.4 Recommended
9.4 Recommended Minimum Support
The features provided by current UPS units vary widely. However experience
shows that a minimum feature set is needed for satisfactory use of the NUT
Project software. For a full list of variables see the Recording Document
9.4.1 Desktop PC Variables
The following variables form a minimum set suitable for Desktop PC. It is
expected that on public power supply failure, the PC will be halted. It will
not restart automatically when power returns.
ups.status with statuses OL OB LB FSD
9.4.2 Unattended servers, additional variables
The following additional variables are needed in a minimum set suitable for an
unattended server. It is expected that on public power supply failure, the
server will be halted. It will restart automatically when power returns.
9.4.3 All systems
Satisfactory use of the NUT Project software requires support for all commands.
All comments welcome. If the list is agreed, I will add the new subsection 9.4
"Recommended Minimum Support" to the I-D
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