On 12/01/2016 09:05, Ladislav Lhotka wrote:
Martin Bjorklund <m...@tail-f.com> writes:
Ladislav Lhotka <lho...@nic.cz> wrote:
On 11 Jan 2016, at 15:58, Robert Wilton <rwil...@cisco.com> wrote:
On 11/01/2016 14:27, Ladislav Lhotka wrote:
On 11 Jan 2016, at 15:11, Juergen Schoenwaelder
<j.schoenwael...@jacobs-university.de> wrote:
On Mon, Jan 11, 2016 at 02:54:36PM +0100, Martin Bjorklund wrote:
Ladislav Lhotka <lho...@nic.cz> wrote:
Hi Gert,
On 11 Jan 2016, at 14:25, Gert Grammel <ggram...@juniper.net> wrote:
Lada,
The requirement says:
D. When a configuration change for any intended configuration
node has been successfully applied to the server (e.g. not
failed, nor deferred due to absent hardware) then the
existence and value of the corresponding applied
configuration node must match the intended configuration
node.
I don't see that this would limit the case you described below. In
your case there is no intended config, hence there is no
"corresponding applied configuration" either.
You are right, the requirement can be interpreted this way. I thought
that applied configuration was supposed to be identical to intended
after some synchronization period.
This is a very important point to clarify. Can there ever be data in
"applied" that is not in "intended"? I think Anees & Rob previously
said "no", but I might be wrong.
If there is time delay between editing intended and the applied config
matching the edits of intended, then I supose this can happen (I
delete a resource from intended but it is still around until intended
has been fully synced). I would find it interesting if some edits are
Using applied config for system-controlled entries would require that
such an entry stays (forever) in applied config even after it has been
deleted from intended.
I think that this would make life harder for clients.
Hmm, I would say the opposite. For one, we could simplify the data
models by reducing the duplicities in configuration and state trees.
This is the old idea of having the "operational state" datastore,
which would be all config true + all config false nodes. One issue
with this is that the semantics of the node is different in the
different data stores, even if the syntax (by definition!) is the
same. In order to handle this properly you need either two different
description statements, or two "sections" within the description
statement.
I think this is not much different from default values. Leafs and
leaf-lists that have them defined in the data model may not be present
in intended config, yet one can consider them to be in applied config.
I think that default values are logically just a way to make the
configuration data more concise. I.e. everywhere you have a default
value then the equivalent configuration could be expressed with a
explicit value set instead.
As such, I think that the default values apply equally to both the
intended and applied configuration.
If after a config request it takes time for the system to apply a
default value, then ideally the applied configuration should have an
explicit leaf to show what value is actually in effect until the default
value has actually been applied in the system.
This does open the question of how do you express the case that no value
has been applied rather than a different value. For the opstate
encoding solution draft that I put forward (or using meta-data), then I
think that it would probably be possible to extend the encoding to
explicitly include this information if required.
Alternatively, and for the other proposed opstate solutions, then I
expect that the most appropriate ideal semantics to handle this scenario
would be to delay marking the parent object as being applied until every
descendent child leaf with a default value set has a value applied in
the system, either to the expected default value (in which case the
child leaf wouldn't need to be present in the applied config), or
transiently to another value (which would be in the applied config until
the system updated and the correct default values have actually been
applied). In real systems, I would have thought that the default values
are often implicitly programmed when the parent containing object is
created anyway, so I suspect that this behaviour wouldn't actually be
that onerous to implement.
Thanks,
Rob
Lada
list interface {
description-config
"The list of configured interfaces on the device.
...";
description-oper
"The list of interfaces on the device.
System-controlled interfaces created by the system are
always present in this list, whether they are configured or
not.
...";
}
/martin
_______________________________________________
netmod mailing list
netmod@ietf.org
https://www.ietf.org/mailman/listinfo/netmod
