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

Darren Ankney darren.ankney at gmail.com
Sun Jan 7 11:58:17 UTC 2024


Hi Andrew,

You might try setting this ("ddns-update-on-renew": false) to true for
a while to see if the client update is sent to ddns, as this is based
on what the server thinks is a renewal not the client.  So even if you
see the client SOLICIT the server will consider this a renewal if it
finds an existing lease, I believe.  It won't hurt anything to try.
Just some extra ddns traffic.

Thank you,

Darren Ankney

On Fri, Jan 5, 2024 at 9:42 AM Andrew Rowson via Kea-users
<kea-users at lists.isc.org> wrote:
>
> Of course.
>
>     {
>         "Dhcp6": {
>             "control-socket": {
>                 "socket-name": "/run/kea/kea-dhcp6.socket",
>                 "socket-type": "unix"
>             },
>             "ddns-override-client-update": true,
>             "ddns-qualifying-suffix": "subdomain.example.com.",
>             "ddns-update-on-renew": false,
>             "dhcp-ddns": {
>                 "enable-updates": true,
>                 "server-ip": "::1"
>             },
>             "expired-leases-processing": {
>                 "flush-reclaimed-timer-wait-time": 25,
>                 "hold-reclaimed-time": 3600,
>                 "max-reclaim-leases": 100,
>                 "max-reclaim-time": 250,
>                 "reclaim-timer-wait-time": 10,
>                 "unwarned-reclaim-cycles": 5
>             },
>             "interfaces-config": {
>                 "interfaces": [
>                     "enp1s0.2"
>                 ]
>             },
>             "lease-database": {
>                 "lfc-interval": 1800,
>                 "name": "/var/lib/kea/kea-leases6.csv",
>                 "type": "memfile"
>             },
>             "reservations-global": false,
>             "reservations-in-subnet": true,
>             "reservations-out-of-pool": true,
>             "option-data": [],
>             "option-def": [
>                 {
>                     "code": 1,
>                     "name": "unifi-address",
>                     "space": "ubnt",
>                     "type": "ipv4-address"
>                 },
>                 {
>                     "array": false,
>                     "code": 6,
>                     "name": "PXEDiscoveryControl",
>                     "space": "vendor-encapsulated-options-space",
>                     "type": "uint8"
>                 },
>                 {
>                     "array": false,
>                     "code": 10,
>                     "name": "PXEMenuPrompt",
>                     "record-types": "uint8,string",
>                     "space": "vendor-encapsulated-options-space",
>                     "type": "record"
>                 },
>                 {
>                     "array": false,
>                     "code": 9,
>                     "name": "PXEBootMenu",
>                     "record-types": "uint16,uint8,string",
>                     "space": "vendor-encapsulated-options-space",
>                     "type": "record"
>                 }
>             ],
>             "host-reservation-identifiers":["duid"],
>             "subnet6": [
>                 {
>                     "interface": "enp1s0.2",
>                     "option-data": [
>                         {
>                             "data": "2001:123:456:e8b0::1b",
>                             "name": "sntp-servers"
>                         }
>                     ],
>                     "pools": [
>                         {
>                             "pool": "2001:123:456:e8b0:beef:f00f::/112"
>                         }
>                     ],
>                     "subnet": "2001:123:456:e8b0::/64",
>                     "reservations": [
>                         {
>                             "duid": "00:03:00:01:b8:27:eb:bf:db:dd",
>                             "hostname": "adsbbot",
>                             "ip-addresses": [
>                                 "2001:123:456:e8b0::f"
>                             ]
>                         },
>                     ]
>                 }
>             ]
>         }
>     }
>
> kea-dhcp-ddns.conf:
>
>     {
>         "DhcpDdns": {
>             "forward-ddns": {
>                 "ddns-domains": [
>                     {
>                         "dns-servers": [
>                             {
>                                 "ip-address": "::1",
>                                 "port": 5333
>                             }
>                         ],
>                         "key-name": "my-key",
>                         "name": "subdomain.example.com."
>                     }
>                 ]
>             },
>             "ip-address": "::1",
>             "port": 53001,
>             "reverse-ddns": {
>                 "ddns-domains": [
>                     {
>                         "dns-servers": [
>                             {
>                                 "ip-address": "::1",
>                                 "port": 5333
>                             }
>                         ],
>                         "key-name": "my-key",
>                         "name": "168.192.in-addr.arpa."
>                     },
>                     {
>                         "dns-servers": [
>                             {
>                                 "ip-address": "::1",
>                                 "port": 5333
>                             }
>                         ],
>                         "key-name": "my-key",
>                         "name": "6.5.4.0.3.2.1.0.1.0.0.2.ip6.arpa."
>                     }
>                 ]
>             },
>             "tsig-keys": [
>                 {
>                     "algorithm": "hmac-sha512",
>                     "name": "my-key",
>                     "secret": "KEY"
>                 }
>             ]
>         }
>     }
>
> Andrew
>
> On Fri, 5 Jan 2024, at 2:19 PM, Darren Ankney wrote:
> > Hi Andrew,
> >
> > The configuration you provided was very simple.  I don't see a problem
> > with it (other than the deprecated stuff already mentioned).  Can you
> > provide an updated configuration including the DDNS settings
> > (obviously with sensitive bits obfuscated)?
> >
> > Thank you,
> >
> > Darren Ankney
> >
> > On Fri, Jan 5, 2024 at 8:48 AM Andrew Rowson via Kea-users
> > <kea-users at lists.isc.org> wrote:
> >>
> >> 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
> >> >> --
> >> >> ISC funds the development of this software with paid support subscriptions. Contact us at https://www.isc.org/contact/ for more information.
> >> >>
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> >> >>
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> >> > information.
> >> >
> >> > To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users.
> >> >
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