[Kea-users] reservations and classes

[Francis Dupont]

Francis Dupont <fdupont at isc.org>
> First I tried to add the class to the host:
> 
>     "client-classes": [
>         {
>             "name": "cl-test",
>             "test": "member('cl-test')"

=> note this does not make sense. If you need a test which is always true
you can use the 'ALL' class but the simplest is to set the class.

>     "reservations": [
>         {
>             "hw-address": "fc:3f:db:36:09:ad",
>             "hostname": "test",
>             "client-classes": [ "cl-test" ]

=> this sets the class but after resource allocation so far too late.

>         }
>     ],
> 
> I got: ALLOC_ENGINE_V4_ALLOC_FAIL

=> unfortunately the expected result.

> Then I tried only with KNOWN:
> 
>     "client-classes": [
>         {
>             "name": "cl-test",
>             "test": "member('KNOWN')"
>         }
>     ],
>     "reservations": [
>         {
>             "hw-address": "fc:3f:db:36:09:ad",
>             "hostname": "test"
>         }
>     ],
> 
> I still got: ALLOC_ENGINE_V4_ALLOC_FAIL

=> this has a chance to work but it requires the right subnet is selected.
If it is not the host reservation won't be look up (can be fixed by
using the global reservation mode) nor the pool. If you have shared networks
it only replaces subnet selection by shared network selection so
you have more choices but perhaps still not enough.

> But "KNOWN" wouldn't be what I want anyway. I want to allow
> hosts with classA only in subnetA, and hosts with classB only in
> subnetB.

=> the problem is that the subnet/shared-network selection is the main
part of the localization phase and for many reasons including a strong
security one it has to be made very soon. Note ISC DHCP has the same
constraint and does not offer a hook which allows to overwrite the
subnet selection.

Regards

Francis Dupont <fdupont at isc.org>

PS: tomorrow we have an internal discussion about ways to make the
client classification easier to use and more powerful. Perhaps we'll
find a solution for your problem as it is already in the list of things
we want to support...