entity manager configurations and dbus interfaces

entity manager configurations and dbus interfaces

[Brad Bishop]

Hi Ed

Will quote a comment from this EM review:

https://gerrit.openbmc-project.xyz/36702

> entity-manager was designed with the tenant that it config files have 
> no knowledge of dbus.

FWIW I had no idea this was the case.

> We've broken that a little with the inventory interfaces on the entity 
> as a short term patch to gain some compatibility, but its easy enough 
> to roll back in the future.

Interesting - so there is a vision here, but I have no idea what it is.  
Can you elaborate on how you envision inventory working if EM is not 
implementing the inventory dbus interfaces?

thx - brad

Re: entity manager configurations and dbus interfaces

[Andrei Kartashev]

Hi Brad,

Thank for bring up this question.
Same as you we have slightly bad view on EM architecture since before
we had only Power-based platforms and now we are working on our first
x86-based one.

Following up the discussion in the review and also mailing discussion
we had early, I now preparing some Implementation Proposal document for
EM-based inventory. I gonna to submit it to docs repo for discussing
and finding our common understanding of how it supposed to be.


On Thu, 2020-09-24 at 10:30 -0400, Brad Bishop wrote:
> Hi Ed
> 
> Will quote a comment from this EM review:
> 
> https://gerrit.openbmc-project.xyz/36702
> 
> > entity-manager was designed with the tenant that it config files
> > have 
> > no knowledge of dbus.
> 
> FWIW I had no idea this was the case.
> 
> > We've broken that a little with the inventory interfaces on the
> > entity 
> > as a short term patch to gain some compatibility, but its easy
> > enough 
> > to roll back in the future.
> 
> Interesting - so there is a vision here, but I have no idea what it
> is.  
> Can you elaborate on how you envision inventory working if EM is not 
> implementing the inventory dbus interfaces?
> 
> thx - brad
-- 
Best regards,
Andrei Kartashev

Re: entity manager configurations and dbus interfaces

[Ed Tanous]

On Thu, Sep 24, 2020 at 7:30 AM Brad Bishop <bradleyb@fuzziesquirrel.com> wrote:
>
> Hi Ed
>
> Will quote a comment from this EM review:
>
> https://gerrit.openbmc-project.xyz/36702
>
> > entity-manager was designed with the tenant that it config files have
> > no knowledge of dbus.
>
> FWIW I had no idea this was the case.
>
> > We've broken that a little with the inventory interfaces on the entity
> > as a short term patch to gain some compatibility, but its easy enough
> > to roll back in the future.
>
> Interesting - so there is a vision here, but I have no idea what it is.
> Can you elaborate on how you envision inventory working if EM is not
> implementing the inventory dbus interfaces?

In the simplest terms, one goal of entity-manager is for an engineer
unfamiliar with OpenBMC to be able to add support for a new component,
be it a baseboard, drive, or add in card, in less than a day.  Dbus
APIs take more than a day to learn, so we need to find a way to
provide a syntax that is self describing (and ideally well documented,
but that's another issue that I'm hoping to tackle soon) as well as
relatively isolated from the complexities of the OpenBMC core.

Another advantage of this is portability, if any wide sweeping
architecture changes happen (ex, we rewrite the core in rust or we
build a DBusless OpenBMC) we have a minimum definition of the things
that are unique about the pieces of hardware we support, and don't
have to re-engineer every piece of hardware that's in the list.


>
> thx - brad

Re: entity manager configurations and dbus interfaces

[Ed Tanous]

On Thu, Sep 24, 2020 at 8:43 AM Andrei Kartashev <a.kartashev@yadro.com> wrote:
>
> Hi Brad,
>
> Thank for bring up this question.
> Same as you we have slightly bad view on EM architecture since before
> we had only Power-based platforms and now we are working on our first
> x86-based one.

Can you go into more specifics about what you don't like about it?  I
know a lot of the complaints I've heard revolves around documentation.
I'm trying to hammer away at that as I get time.  Is there any other
low hanging fruit that we can fix that's entity-manager specific?

>
> Following up the discussion in the review and also mailing discussion
> we had early, I now preparing some Implementation Proposal document for
> EM-based inventory. I gonna to submit it to docs repo for discussing
> and finding our common understanding of how it supposed to be.
>
>
> On Thu, 2020-09-24 at 10:30 -0400, Brad Bishop wrote:
> > Hi Ed
> >
> > Will quote a comment from this EM review:
> >
> > https://gerrit.openbmc-project.xyz/36702
> >
> > > entity-manager was designed with the tenant that it config files
> > > have
> > > no knowledge of dbus.
> >
> > FWIW I had no idea this was the case.
> >
> > > We've broken that a little with the inventory interfaces on the
> > > entity
> > > as a short term patch to gain some compatibility, but its easy
> > > enough
> > > to roll back in the future.
> >
> > Interesting - so there is a vision here, but I have no idea what it
> > is.
> > Can you elaborate on how you envision inventory working if EM is not
> > implementing the inventory dbus interfaces?
> >
> > thx - brad
> --
> Best regards,
> Andrei Kartashev
>
>

Re: entity manager configurations and dbus interfaces

[Andrei Kartashev]

Well, I didn't meant EM is bad, it was "I don't understand well how all
this supposed to work".
Now I have number of inputs from you in different topics but I still
need to bring things together to get the picture.

On Thu, 2020-09-24 at 08:54 -0700, Ed Tanous wrote:
> On Thu, Sep 24, 2020 at 8:43 AM Andrei Kartashev <
> a.kartashev@yadro.com> wrote:
> > Hi Brad,
> > 
> > Thank for bring up this question.
> > Same as you we have slightly bad view on EM architecture since
> > before
> > we had only Power-based platforms and now we are working on our
> > first
> > x86-based one.
> 
> Can you go into more specifics about what you don't like about it?  I
> know a lot of the complaints I've heard revolves around
> documentation.
> I'm trying to hammer away at that as I get time.  Is there any other
> low hanging fruit that we can fix that's entity-manager specific?
> 
> > Following up the discussion in the review and also mailing
> > discussion
> > we had early, I now preparing some Implementation Proposal document
> > for
> > EM-based inventory. I gonna to submit it to docs repo for
> > discussing
> > and finding our common understanding of how it supposed to be.
> > 
> > 
> > On Thu, 2020-09-24 at 10:30 -0400, Brad Bishop wrote:
> > > Hi Ed
> > > 
> > > Will quote a comment from this EM review:
> > > 
> > > https://gerrit.openbmc-project.xyz/36702
> > > 
> > > > entity-manager was designed with the tenant that it config
> > > > files
> > > > have
> > > > no knowledge of dbus.
> > > 
> > > FWIW I had no idea this was the case.
> > > 
> > > > We've broken that a little with the inventory interfaces on the
> > > > entity
> > > > as a short term patch to gain some compatibility, but its easy
> > > > enough
> > > > to roll back in the future.
> > > 
> > > Interesting - so there is a vision here, but I have no idea what
> > > it
> > > is.
> > > Can you elaborate on how you envision inventory working if EM is
> > > not
> > > implementing the inventory dbus interfaces?
> > > 
> > > thx - brad
> > --
> > Best regards,
> > Andrei Kartashev
> > 
> > 
-- 
Best regards,
Andrei Kartashev

Re: entity manager configurations and dbus interfaces

[James Feist]

On 9/24/2020 8:50 AM, Ed Tanous wrote:
> On Thu, Sep 24, 2020 at 7:30 AM Brad Bishop <bradleyb@fuzziesquirrel.com> wrote:
>>
>> Hi Ed
>>
>> Will quote a comment from this EM review:
>>
>> https://gerrit.openbmc-project.xyz/36702
>>
>>> entity-manager was designed with the tenant that it config files have
>>> no knowledge of dbus.
>>
>> FWIW I had no idea this was the case.
>>
>>> We've broken that a little with the inventory interfaces on the entity
>>> as a short term patch to gain some compatibility, but its easy enough
>>> to roll back in the future.
>>
>> Interesting - so there is a vision here, but I have no idea what it is.
>> Can you elaborate on how you envision inventory working if EM is not
>> implementing the inventory dbus interfaces?
> 
> In the simplest terms, one goal of entity-manager is for an engineer
> unfamiliar with OpenBMC to be able to add support for a new component,
> be it a baseboard, drive, or add in card, in less than a day.  Dbus
> APIs take more than a day to learn, so we need to find a way to
> provide a syntax that is self describing (and ideally well documented,
> but that's another issue that I'm hoping to tackle soon) as well as
> relatively isolated from the complexities of the OpenBMC core.
> 
> Another advantage of this is portability, if any wide sweeping
> architecture changes happen (ex, we rewrite the core in rust or we
> build a DBusless OpenBMC) we have a minimum definition of the things
> that are unique about the pieces of hardware we support, and don't
> have to re-engineer every piece of hardware that's in the list.
> 

While I agree with this, to fit in the current architecture, I'm not 
sure its entirely possible. We already expose some d-bus interfaces from 
the configuration files: 
https://github.com/openbmc/entity-manager/blob/0a2ab3c911d35c4c8421c47a7ce83d9341237785/configurations/WFT%20Baseboard.json#L1601. 
This particular change does add a new prescience to be able to add them 
anywhere, which I don't think should be taken lightly. However I'm not 
sure if there's any better way to support lower level assets interfaces 
such as a Fan FRU, unless you think it'd be better to add that to the 
FanSensor? I'm not sure I like that idea any better.

> 
>>
>> thx - brad

Re: entity manager configurations and dbus interfaces

[Andrei Kartashev]

Hi,

Here is first draft for document I mentioned. I would like everyone
interested in entity manager participate discussion there:

https://gerrit.openbmc-project.xyz/c/openbmc/docs/+/36914


On Thu, 2020-09-24 at 10:30 -0400, Brad Bishop wrote:
> Hi Ed
> 
> Will quote a comment from this EM review:
> 
> https://gerrit.openbmc-project.xyz/36702
> 
> > entity-manager was designed with the tenant that it config files
> > have 
> > no knowledge of dbus.
> 
> FWIW I had no idea this was the case.
> 
> > We've broken that a little with the inventory interfaces on the
> > entity 
> > as a short term patch to gain some compatibility, but its easy
> > enough 
> > to roll back in the future.
> 
> Interesting - so there is a vision here, but I have no idea what it
> is.  
> Can you elaborate on how you envision inventory working if EM is not 
> implementing the inventory dbus interfaces?
> 
> thx - brad
-- 
Best regards,
Andrei Kartashev