[Kea-users] Kea-dhcp6 always warns with ALLOC_ENGINE_V6_ALLOC_FAIL_SUBNET when allocating reserved address

Andrew Rowson andrew at growse.com
Fri Jan 5 13:48:14 UTC 2024


Thanks for the advice / pointers. I've updated the config (behaviour is the same).

One thing I've also noticed is that if I add in a ddns configuration, DHCP requests from the reserved host doesn't trigger a ddns update, whereas other requests do. I wonder if that's related?

Andrew

On Thu, 4 Jan 2024, at 9:51 PM, Darren Ankney wrote:
> Hi Andrew,
>
> This is also probably not the solution to these logs, but I notice you
> also have: "reservation-mode": "out-of-pool",  See here:
> https://kea.readthedocs.io/en/kea-2.4.1/arm/dhcp6-srv.html#fine-tuning-dhcpv6-host-reservation
> where it explains that this is deprecated: "Since Kea 1.9.1, the
> reservation-mode parameter is replaced by the reservations-global,
> reservations-in-subnet and reservations-out-of-pool flags. The flags
> can be activated independently and can produce various combinations,
> some of them being unsupported by the deprecated reservation-mode."
>
> Additionally, you may want to move the reservations-global,
> reservations-in-subnet and reservations-out-of-pool flags to the
> global area.  Their intention is to make allocations happen with less
> CPU by telling Kea where it might find reservations.  So, at least the
> "reservations-global": false, parameter should be global to prevent
> kea from wasting time looking there for a reservation.
>
> You can, of course, suppress these log messages by setting a specific
> logger for kea-dhcp6.alloc-engine and setting severity to ERROR which
> will cause only ERROR and FATAL messages from the
> kea-dhcp6.alloc-engine logger to be logged see here:
> https://kb.isc.org/docs/kea-logging-configuration and here:
> https://kea.readthedocs.io/en/kea-2.4.1/arm/logging.html for further
> information.
>
> Thank you,
>
> Darren Ankney
>
> On Thu, Jan 4, 2024 at 12:51 PM Andrew Rowson via Kea-users
> <kea-users at lists.isc.org> wrote:
>>
>> My bad - typo in the email. It's correct on the server:
>>
>>     "subnet": "2001:123:456:e8b0::/64",
>>     "reservations-global": false,
>>     "reservations-in-subnet": true,
>>     "reservations-out-of-pool": true,
>>     "reservations": [
>>
>> On Thu, 4 Jan 2024, at 5:17 PM, Bob Harold wrote:
>> > On Thu, Jan 4, 2024 at 12:10 PM Andrew Rowson via Kea-users
>> > <kea-users at lists.isc.org> wrote:
>> >> Hi,
>> >>
>> >> I'm using isc-kea-dhcp6 (2.4.1-isc20231123184533) on Debian bookworm and am having a minor logging issue. I've got a minimal config that defines a single subnet, an allocatable pool within that subnet and a single reservation.
>> >>
>> >> The host gets its reserved IP successfully, but there's always a WARN log dance in the kea logs with ALLOC_ENGINE_V6_ALLOC_FAIL_SUBNET, ALLOC_ENGINE_V6_ALLOC_FAIL_NO_POOLS and ALLOC_ENGINE_V6_ALLOC_FAIL_CLASSES.
>> >>
>> >> Are these warnings expected, or have I misunderstood something about the configuration?
>> >>
>> >> Thanks,
>> >> Andrew
>> >>
>> >> Config:
>> >>
>> >>     {
>> >>         "Dhcp6": {
>> >>             "interfaces-config": {
>> >>                 "interfaces": [
>> >>                     "enp1s0.2",
>> >>                 ]
>> >>             },
>> >>             "lease-database": {
>> >>                 "lfc-interval": 1800,
>> >>                 "name": "/var/lib/kea/kea-leases6.csv",
>> >>                 "type": "memfile"
>> >>             },
>> >>             "subnet6": [
>> >>                 {
>> >>                     "interface": "enp1s0.2",
>> >>                     "reservation-mode": "out-of-pool",
>> >>                     "pools": [
>> >>                         {
>> >>                             "pool": "2001:123:456:e8b0:beef:f00f::/112"
>> >>                         }
>> >>                     ],
>> >>                     "reservations-global": false,
>> >>                     "reservations-in-subnet": true,
>> >>                     "eservations-out-of-pool": true,
>> >
>> > Probably not the solution, but the line above seems to be missing the
>> > first letter.  Is it that way on the server?
>> >
>> >>                     "subnet": "2001:123:456:e8b0::/64",
>> >>                     "reservations": [
>> >>                         {
>> >>                             "duid": "00:03:00:01:b8:27:eb:bf:db:dd",
>> >>                             "hostname": "myhost",
>> >>                             "ip-addresses": [
>> >>                                 "2001:123:456:e8b0::f"
>> >>                             ]
>> >>                         }
>> >>                     ]
>> >>                 }
>> >>             ],
>> >>             "valid-lifetime": 1800
>> >>         }
>> >>     }
>> >>
>> >> Logs:
>> >>
>> >>     INFO [kea-dhcp6.dhcp6/182198.139733472774592] DHCP6_STARTED Kea DHCPv6 server version 2.4.1 started
>> >>     INFO  [kea-dhcp6.leases/182198.139733433005760] DHCP6_LEASE_ADVERT duid=[00:03:00:01:b8:27:eb:bf:db:dd], tid=0x3e9640: lease for address 2001:123:456:e8b0::f and iaid=1746070577 will be advertised
>> >>     WARN  [kea-dhcp6.alloc-engine/182198.139733433005760] ALLOC_ENGINE_V6_ALLOC_FAIL_SUBNET duid=[00:03:00:01:b8:27:eb:bf:db:dd], tid=0x3e9640: failed to allocate an IPv6 lease in the subnet 2001:123:456:e8b0::/64, subnet-id 1, shared network (none)
>> >>     WARN  [kea-dhcp6.alloc-engine/182198.139733433005760] ALLOC_ENGINE_V6_ALLOC_FAIL_NO_POOLS duid=[00:03:00:01:b8:27:eb:bf:db:dd], tid=0x3e9640: no pools were available for the lease allocation
>> >>     WARN  [kea-dhcp6.alloc-engine/182198.139733433005760] ALLOC_ENGINE_V6_ALLOC_FAIL_CLASSES duid=[00:03:00:01:b8:27:eb:bf:db:dd], tid=0x3e9640: Failed to allocate an IPv6 address for client with classes: ALL, KNOWN
>> >>     INFO  [kea-dhcp6.leases/182198.139733424613056] DHCP6_LEASE_ALLOC duid=[00:03:00:01:b8:27:eb:bf:db:dd], tid=0x137d91: lease for address 2001:123:456:e8b0::f and iaid=1746070577 has been allocated for 1800 seconds
>> >> --
>> >>
>> > --
>> > Bob Harold
>> --
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