IPMI LAN command story design - try 3rd send

[Tom Joseph]

On Thursday 14 December 2017 06:00 PM, Jeremy Kerr wrote:
> Hi Tom,
>
>>> Requiring non-standard command to be issued causes a disconnect between
>>> user expectations and our implementation. We'd have to document this
>>> difference in behaviour for every potential sysadmin interacting with
>>> OpenBMC.
>>   The command to apply BMC network settings on OpenBMC IPMI reference
>>   implementation is set channel access, which is a standard command
>>   mentioned in the IPMI specification.
> It may be a standard command, but using it in this context certainly
> isn't standard, nor even a common convention.
>
> The issue is that we're introducing an "unusual" step for this
> configuration process, and expecting all users to know about it.
>
>>   It is not clear to me from the IPMI specification, on which
>> command/condition
>>   the BMC network settings are applied.
> Ideally, the settings should be applied as soon as the 'Set in progress'
> flag indicates that the change is complete.
>
> Adding the 10-second delay allows users to "batch" multiple changes,
> meaning that network connectivity isn't lost between those changes. This
> is purely to allow ipmitool (which doesn't have a facility to make
> multiple changes before indicating that the change is complete) to be
> used over the network to change the lan configuration (which is a bit
> risky regardless...).

Yeah all this lack of clarity, arises from a lack of mechanism in IPMI to
apply multiple changes (IP address, netmask gateway) together. In the
ipmitool implementation the set-in-progress is cleared after each network
parameter setting.


>
> For doing this over the in-band interface, there is no harm in applying
> the settings immediately.
>
> To implement something complying to a "principle of least surprise", I'd
> suggest that we should:
>
>   - batch changes, and have them applied after 10 seconds from clearing
>     the set-in-progress flag
>
>   - submit patches to ipmitool to allow multiple changes to be applied
>     at once (ie, one clearing of the set-in-progress flag).

I prefer the second option of allowing ipmitool to explicitly clear the 
set-in-progress flag.
thus allowing multiple changes to take effect.

The first option is really  "unusual way" to get this done, to overcome 
a specification shortcoming.
>
> Regards,
>
>
> Jeremy
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