Re: [netmod] AD review of draft-ietf-netmod-entity-06

[Benoit Claise <[e-mail]>]

Dear all,

draft-ietf-netmod-entity is the IESG telechat today.
In light of this discussion below, which I consider part of the IETF LC, 
I'll be deferring the document to the next IESG telechat in two weeks.
You have a few days to provide feedback on this propose solution 2.

Regards, Benoit (OPS AD).
> Hi,
>
> To summarize this, I think we have three options for the three nodes
> 'model-name', 'mfg-name', and 'serial-num':
>
>    1.  Do nothing (keep the nodes as config true).
>
>    2.  Make these three nodes config false (fairly simple change).
>        (vendors can augment w/ their own config true nodes).
>
>    3.  Add three new nodes for the configured values.
>
>
> After thinking about this some more, and discussing with Benoit, I
> think the best path forward is to do 2, i.e., mark the nodes
> 'model-name', 'mfg-name', and 'serial-num' as "config false".  As such
> they would not be configurable, and thus contain the detected values.
> If no value is detected, the node is not present.
>
> Note that 1 or 3 can be done in a future update to this module (or by
> a vendor).
>
>
> /martin
>
>
> Martin Bjorklund <[e-mail]> wrote:
>> Hi,
>>
>> "Bogaert, Bart (Nokia - BE/Antwerp)" <[e-mail]> wrote:
>>> Hi,
>>>
>>> --- snip ---
>>>
>>>> state.”, so the above sentence only applies for the second case below.
>>> Ok.
>>>
>>>> 2. The second case is that something is detected but it can’t be read.
>>>> We do not see a reason to use the value configured for the leafs
>>>> ‘serial-num’, ‘mfg-name’ and ‘model-name’ of a matching entry in the
>>>> configuration data.  These leafs are defined as optional so why would
>>>> we report something entered by an operator in the operational
>>>> datastore that intends to report on what is detected?  Is it not
>>>> better to not report them at all?  In an NMDA context it would be
>>>> possible to have a different value (or no value at all) for certain
>>>> leafs while there is something in the running/intended datastore.
>>> The normal NMDA procedure for a configuration leaf is to repeat it in
>>> operational state.  This is then the "applied configuration".
>>> I don't think we should have a special rule for these leafs.
>>>
>>> This also means that a client that just wants to read all the serial
>>> numbers can do so from one place, the operational state, regardless of
>>> how they came into existance.
>>>
>>> [Bogaert, Bart ]
>>>
>>> We do understand that a target of NMDA is to read out the actually
>>> applied data in one request.  But the result should not be
>>> confusion. A key word is “applied”.
>>>
>>> Section 5.3 of draft-ietf-netmod-revised-datastores-09 also contains
>>> (I put a part of the section between ***):
>>> The datastore schema for <operational> MUST be a superset of the
>>> combined datastore schema used in all configuration datastores except
>>> that configuration data nodes supported in a configuration datastore
>>> ***MAY be omitted from <operational> if a server is not able to
>>> accurately report them ***.
>> Note that this text talks about the *schema*.  It is intended for
>> servers to migrate to NMDA without having to instrument all config
>> nodes in <operational> immediately.  If you apply this to
>> ietf-hardware, it could be a server that implements the node
>> "serial-num" in config, but not in <operational> (which would be
>> weird).
>>
>>> For example, it is expected that the value of multiple leafs need to
>>> be a consistent set, e.g. the mfg-name, the model-name, and the
>>> serial-num.
>>> Suppose we have a use case in which a hardware component is
>>> planned/configured (e.g. a board supporting DSL interfaces) but a
>>> different one is plugged (e.g. a board supporting ethernet
>>> interfaces).
>>> Suppose it is possible to read some fields on the detected component
>>> but due to an issue not to read other fields.
>>> If in that case the operational datastore will be completed with the
>>> data taken from the running datastore, then the presented view might
>>> be inconsistent.
>> This is true for other similar nodes as well - "asset-id" and "uri".
>>
>>> The question is also: what data is applied? Our assumption: if there
>>> is a mismatch between detected versus configured hardware, then the
>>> interface/service related data that is configured consistently with
>>> the planned hardware is not applied on the mismatching
>>> hardware. I.e. the detected hardware is not brought in service so not
>>> ‘applied’, the operational datastore only (accurately) reports on what
>>> is detected.
>> If there is a mismatch and the server doesn't apply the configured
>> values, then obviously the configured 'mfg-name' etc are not copied to
>> <operational>.
>>
>>> We do not see this as a special rule for this data but rather would
>>> apply a general rule:
>>> -	if there is a ‘missing resource’, then the data is not reported in the
>>>   	operational datastore.
>>> -	If the server is not able to report accurately, then the data is
>>>   	omitted from the operational
>> I think that if you want complete separation between the values of
>> 'mfg-name', 'model-name', and 'serial-num' in configuration and
>> operational state, then these should be modelled as separate leafs.
>> We should have a config false leaf 'serial-num' that only contains the
>> detected value (if found), and a config true leaf 'config-serial-num'
>> or something, that contains the configured serial number.
>>
>> But if this is the case, I wonder if it wouldn't be better to leave
>> such additional config objects to vendors, and simply make these three
>> nodes config false in ietf-hardware.
>>
>>
>> /martin
>>
>>> Regards, Bart
>>>
>>> /martin
>>>
>>>
>>>> Best regards, Bart
>>>>
>>>> -----Original Message-----
>>>> From: netmod [mailto:[e-mail]] On Behalf Of Robert
>>>> Wilton
>>>> Sent: Thursday, December 21, 2017 4:14 PM
>>>> To: Martin Bjorklund <[e-mail]>; [e-mail]
>>>> Subject: Re: [netmod] AD review of draft-ietf-netmod-entity-06
>>>>
>>>> Hi Martin,
>>>>
>>>>
>>>> On 21/12/2017 11:37, Martin Bjorklund wrote:
>>>>> Hi,
>>>>>
>>>>> I need WG input on this issue.  The question is how to handle
>>>>> 'serial-num', 'mfg-name', and 'model-name'.  I think they should all
>>>>> be treated the same.  Based on previous WG discussion (see e.g. the
>>>>> mail thread "draft-ietf-netmod-entity issue #13"), I think they
>>>>> should all be configurable, but the configured value is only used in
>>>>> operational state if the system cannot read it from the hardware.
>>>> I think that this approach is probably OK:
>>>>    - The client can always see the real value if it is available.
>>>>    - If it is not available then they can assign a value via
>>>> configuration.
>>>>
>>>> I was also considering an alternative approach of having a separate
>>>> set of config false leaves for the "burnt in values".  And then having
>>>> the configurable leaves always override the default operational
>>>> values. E.g. similar to how an interface MAC address would expect to
>>>> be handled.
>>>>
>>>> But one set of leaves is probably sufficient.
>>>>
>>>> Thanks,
>>>> Rob
>>>>
>>>>
>>>>> So I suggest the following changes:
>>>>>
>>>>> OLD:
>>>>>
>>>>>         leaf serial-num {
>>>>>           type string;
>>>>>           config false;
>>>>>           description
>>>>>             "The vendor-specific serial number string for the
>>>>>              component.  The preferred value is the serial number
>>>>>              string actually printed on the component itself (if
>>>>>              present).";
>>>>>           reference "RFC 6933: entPhysicalSerialNum";
>>>>>         }
>>>>>
>>>>> NEW:
>>>>>
>>>>>         leaf serial-num {
>>>>>           type string;
>>>>>           description
>>>>>             "The vendor-specific serial number string for the
>>>>>              component.  The preferred value is the serial number
>>>>>              string actually printed on the component itself (if
>>>>>              present).
>>>>>
>>>>>              This leaf can be configured.  There are two use cases for
>>>>>              this; as a 'post-it' note if the server cannot determine
>>>>>              this value from the component, or when pre-provisioning a
>>>>>              component.
>>>>>
>>>>>              If the server can determine the serial number from the
>>>>>              component, then that value is always used in operational
>>>>>              state, even if another value has been configured.";
>>>>>           reference "RFC 6933: entPhysicalSerialNum";
>>>>>         }
>>>>>
>>>>> And corresponding text for 'mfg-name' and 'model-name'.
>>>>>
>>>>> And also:
>>>>>
>>>>> OLD:
>>>>>
>>>>>            When the server detects a new hardware component, it
>>>>>            initializes a list entry in the operational state.
>>>>>
>>>>>            If the server does not support configuration of hardware
>>>>>            components, list entries in the operational state are
>>>>>            initialized with values for all nodes as detected by the
>>>>>            implementation.
>>>>>
>>>>>            Otherwise, the following procedure is followed:
>>>>>
>>>>>              1. If there is an entry in the /hardware/component list in
>>>>>                 the intended configuration with values for the nodes
>>>>>                 'class', 'parent', 'parent-rel-pos' that are equal to
>>>>>                 the detected values, then:
>>>>>
>>>>>              1a. If the configured entry has a value for 'mfg-name'
>>>>>                  that is equal to the detected value, or if the
>>>>>                  'mfg-name' value cannot be detected, then the list
>>>>>                  entry in the operational state is initialized with the
>>>>>                  configured values for all configured nodes, including
>>>>>                  the 'name'.
>>>>>
>>>>>                  Otherwise, the list entry in the operational state is
>>>>>                  initialized with values for all nodes as detected by
>>>>>                  the implementation.  The implementation may raise an
>>>>>                  alarm that informs about the 'mfg-name' mismatch
>>>>>                  condition.  How this is done is outside the scope of
>>>>>                  this document.
>>>>>
>>>>>              1b. Otherwise (i.e., there is no matching configuration
>>>>>                  entry), the list entry in the operational state is
>>>>>                  initialized with values for all nodes as detected by
>>>>>                  the implementation.
>>>>>
>>>>>            If the /hardware/component list in the intended
>>>>>            configuration is modified, then the system MUST behave as if
>>>>>            it re-initializes itself, and follow the procedure in
>>>>> (1).";
>>>>>
>>>>> NEW:
>>>>>
>>>>>            When the server detects a new hardware component, it
>>>>>            initializes a list entry in the operational state.
>>>>>
>>>>>            If the server does not support configuration of hardware
>>>>>            components, list entries in the operational state are
>>>>>            initialized with values for all nodes as detected by the
>>>>>            implementation.
>>>>>
>>>>>            Otherwise, the following procedure is followed:
>>>>>
>>>>>              1. If there is an entry in the /hardware/component list in
>>>>>                 the intended configuration with values for the nodes
>>>>>                 'class', 'parent', 'parent-rel-pos' that are equal to
>>>>>                 the detected values, then the list entry in operational
>>>>>                 state is initialized with the configured values,
>>>>>                 including the 'name'.  The leafs 'serial-num',
>>>>>                 'mfg-name', and 'model-name' are treated specially; see
>>>>>                 their descriptions for details.
>>>>>
>>>>>              2. Otherwise (i.e., there is no matching configuration
>>>>>                 entry), the list entry in the operational state is
>>>>>                 initialized with values for all nodes as detected by
>>>>>                 the implementation.
>>>>>
>>>>>            If the /hardware/component list in the intended
>>>>>            configuration is modified, then the system MUST behave as if
>>>>>            it re-initializes itself, and follow the procedure in
>>>>> (1).";
>>>>>
>>>>>
>>>>>
>>>>> /martin
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Benoit Claise <[e-mail]> wrote:
>>>>>> On 12/20/2017 4:00 PM, Martin Bjorklund wrote:
>>>>>>> Benoit Claise <[e-mail]> wrote:
>>>>>>>> Hi Martin,
>>>>>>>>
>>>>>>>> Thanks.
>>>>>>>> Only kept the relevant excerpts.
>>>>>>>>>> - Some objects are read-write in RFC6933:
>>>>>>>>>>           entPhysicalSerialNum
>>>>>>>>>>           entPhysicalAlias
>>>>>>>>>>           entPhysicalAssetID
>>>>>>>>>>           entPhysicalUris
>>>>>>>>>>
>>>>>>>>>> For example, entPhysicalSerialNum being read-write always bothered
>>>>>>>>>> me.
>>>>>>>>>> serial-num is now "config false", which is a good news IMO.
>>>>>>>>> Actually, this was not the intention.  In
>>>>>>>>> draft-ietf-netmod-entity-03 this is configurable.  I missed this
>>>>>>>>> in the conversion to NMDA.
>>>>>>>> Ah. So no good news in this case...
>>>>>>>>>> In the reverse direction, entPhysicalMfgName is read-only in
>>>>>>>>>> RFC6933, while it's "config true" in draft-ietf-netmod-entity
>>>>>>>>> Yes, this was added per request from the WG.  See e.g. the
>>>>>>>>> thread "draft-ietf-netmod-entity issue #13".
>>>>>>>> Sure. It was mainly an observation.
>>>>>>>>> However, I think that what we have now is probably not correct.
>>>>>>>>> I think that all nodes 'serial-num', 'mfg-name', and 'model-name'
>>>>>>>>> should be config true, and the description of list 'component'
>>>>>>>>> updated to reflect that all these tree leafs are handled the same way.
>>>>>>>>>
>>>>>>>>> I would like to know what the WG thinks about this.
>>>>>>>> Talking as a contributor this time.
>>>>>>>> It seems that inventory management is kind of broken when someone
>>>>>>>> can change 'serial-num', 'mfg-name', and 'model-name.
>>>>>>> They can't really change them.  The configured values are only
>>>>>>> used (i.e. visible in the operational state) if the device cannot
>>>>>>> detect them automatically.  I.e., they work as "post-it" notes only.
>>>>>> If I look at, for example, the mfg-name, description, this is not
>>>>>> what it says.
>>>>>>
>>>>>>      leaf mfg-name {
>>>>>>              type string;
>>>>>>              description
>>>>>>                "The name of the manufacturer of this physical component.
>>>>>>                 The preferred value is the manufacturer name string
>>>>>>                 actually printed on the component itself (if present).
>>>>>>
>>>>>>                 Note that comparisons between instances of the model-name,
>>>>>>                 firmware-rev, software-rev, and the serial-num nodes are
>>>>>>                 only meaningful amongst component with the same value of
>>>>>>                 mfg-name.
>>>>>>
>>>>>>                 If the manufacturer name string associated with the
>>>>>>                 physical component is unknown to the server, then this
>>>>>>                 node is not instantiated.";
>>>>>>              reference "RFC 6933 <https://tools.ietf.org/html/rfc6933>:
>>>>>>              entPhysicalMfgName";
>>>>>>
>>>>>> Regards, Benoit
>>>>>>
>>>>>>> /martin
>>>>>>> .
>>>>>>>
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>>>>>
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