[Kea-users] Excess update conflicts caused HA termination

[Elton, Norman N]

>From a previous discussion (https://gitlab.isc.org/isc-projects/kea/-/work_items/3928#note_640594), I know that having multiple DHCP relays running simultaneously can cause lease update conflicts as a single request can be processed by two different Kea threads concurrently. We have observed this in our environment. I’ve checked our logs and see messages consistent with updates failing due to our multiple relays, rather than a single client misbehaving. I’ll include a snippet below. We just experienced our first HA_LEASE_UPDATE_REJECTS_CAUSED_TERMINATION.

Unfortunately we cannot suppress the relays from forwarding requests simultaneously.

We have max-rejected-lease-updates set to 10. I suppose I could crank this number up. Or disable the feature by setting it to zero.

We’re running Kea 2.6.4. Are there any other options that could help here?

Thank you!

Norman



[kea-dhcp4.dhcp4.131042717603520] DHCP4_QUERY_LABEL received query: [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d
[kea-dhcp4.packets.131042717603520] DHCP4_PACKET_RECEIVED [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: DHCPDISCOVER (type 1) received from 192.168.136.2 to 192.168.10.155 on interface bond0.10
[kea-dhcp4.dhcp4.131042725996224] DHCP4_QUERY_LABEL received query: [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d
[kea-dhcp4.packets.131042725996224] DHCP4_PACKET_RECEIVED [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: DHCPDISCOVER (type 1) received from 192.168.136.4 to 192.168.10.155 on interface bond0.10
[kea-dhcp4.leases.131042717603520] DHCP4_LEASE_OFFER [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: lease 192.168.137.77 will be offered
[kea-dhcp4.packets.131042717603520] DHCP4_PACKET_SEND [hwtype=1 d4:dc:09:24:da:26], cid=[no info], tid=0xd681062d: trying to send packet DHCPOFFER (type 2) from 192.168.10.155:67 to 192.168.136.2:67 on interface bond0.10
[kea-dhcp4.leases.131042700818112] DHCP4_LEASE_OFFER [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: lease 192.168.137.77 will be offered
[kea-dhcp4.packets.131042700818112] DHCP4_PACKET_SEND [hwtype=1 d4:dc:09:24:da:26], cid=[no info], tid=0xd681062d: trying to send packet DHCPOFFER (type 2) from 192.168.10.155:67 to 192.168.136.4:67 on interface bond0.10
[kea-dhcp4.dhcp4.131042709210816] DHCP4_QUERY_LABEL received query: [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d
[kea-dhcp4.packets.131042709210816] DHCP4_PACKET_RECEIVED [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: DHCPDISCOVER (type 1) received from 192.168.136.3 to 192.168.10.155 on interface bond0.10
[kea-dhcp4.leases.131042709210816] DHCP4_LEASE_OFFER [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: lease 192.168.137.77 will be offered
[kea-dhcp4.packets.131042709210816] DHCP4_PACKET_SEND [hwtype=1 d4:dc:09:24:da:26], cid=[no info], tid=0xd681062d: trying to send packet DHCPOFFER (type 2) from 192.168.10.155:67 to 192.168.136.3:67 on interface bond0.10
[kea-dhcp4.dhcp4.131042717603520] DHCP4_QUERY_LABEL received query: [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d
[kea-dhcp4.packets.131042717603520] DHCP4_PACKET_RECEIVED [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: DHCPREQUEST (type 3) received from 192.168.136.2 to 192.168.10.155 on interface bond0.10
[kea-dhcp4.dhcp4.131042700818112] DHCP4_QUERY_LABEL received query: [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d
[kea-dhcp4.dhcp4.131042709210816] DHCP4_QUERY_LABEL received query: [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d
[kea-dhcp4.packets.131042700818112] DHCP4_PACKET_RECEIVED [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: DHCPREQUEST (type 3) received from 192.168.136.4 to 192.168.10.155 on interface bond0.10
[kea-dhcp4.packets.131042709210816] DHCP4_PACKET_RECEIVED [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: DHCPREQUEST (type 3) received from 192.168.136.3 to 192.168.10.155 on interface bond0.10
[kea-dhcp4.leases.131042717603520] DHCP4_LEASE_ALLOC [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: lease 192.168.137.77 has been allocated for 86400 seconds
[kea-dhcp4.leases.131042717603520] DHCP4_LEASE_ALLOC [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d: lease 192.168.137.77 has been allocated for 86400 seconds
[kea-dhcp4.commands.131131318404800] COMMAND_RECEIVED Received command 'lease4-update'
[kea-dhcp4.commands.131131293226688] COMMAND_RECEIVED Received command 'lease4-update'
[kea-dhcp4.lease-cmds-hooks.131131293226688] LEASE_CMDS_UPDATE4_CONFLICT lease4-update command failed due to conflict (parameters: { "expire": 1790021221, "force-create": true, "fqdn-fwd": false, "fqdn-rev": false, "hostname": "", "hw-address": "d4:dc:09:24:da:26", "ip-address": "192.168.137.77", "origin": "ha-partner", "state": 0, "subnet-id": 2163181568, "valid-lft": 86400 }, reason: ResourceBusy: IP address:192.168.137.77 could not be updated.)
[kea-dhcp4.ha-hooks.131042776352448] HA_LEASE_UPDATE_CONFLICT KEA_02: lease update [hwtype=1 d4:dc:09:24:da:26], cid=[01:d4:dc:09:24:da:26], tid=0xd681062d sent to KEA_01 (http://192.168.10.154:3000) returned conflict status code: ResourceBusy: IP address:192.168.137.77 could not be updated. (error code 4)
[kea-dhcp4.packets.131042700818112] DHCP4_PACKET_SEND [hwtype=1 d4:dc:09:24:da:26], cid=[no info], tid=0xd681062d: trying to send packet DHCPACK (type 5) from 192.168.10.155:67 to 192.168.136.2:67 on interface bond0.10
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