Hi Sébastien, The frequent disconnections could be anything. Is there anything in the MySQL logs? Also, is this MySQL or MariaDB? MySQL 8 has some performance issues that affect Kea pretty badly (See here: https://kea.readthedocs.io/en/kea-2.6.1/arm/admin.html#mysql-5-7-vs-mysql-8-vs-mariadb-10-and-11 )
If you haven't already found them, there are a couple of articles about MySQL clusters and Kea: https://kb.isc.org/docs/getting-started-with-galera-or-percona-for-kea https://kb.isc.org/docs/experimental-mysql-clusters-for-kea (this one might not be relevant) Thank you, Darren Ankney On Wed, Jan 8, 2025 at 4:51 AM Sébastien Nauer via Kea-users < kea-users@lists.isc.org> wrote: > Hello, > > We are experiencing issues with configuring a KEA cluster in > high-availability mode with a GALERA Cluster database backend. > > As we'd like to use the database cluster for managing leases > synchronization : > > - we configured KEA High Availability mode like this for disabling > lease sync & update : > > "high-availability": [ > { > "this-server-name": "kea01", > "mode": "load-balancing", > "heartbeat-delay": 10000, > "max-response-delay": 10000, > "max-ack-delay": 5000, > "max-unacked-clients": 5, > "send-lease-updates": false, > "sync-leases": false, > "sync-page-limit": 10000, > "sync-timeout": 30000, > "multi-threading": { > "enable-multi-threading": true, > "http-dedicated-listener": true, > "http-listener-threads": 0, > "http-client-threads": 0 > }, > "peers": [ > { > "name": "kea0&", > "url": "http://1.2.3.4:8080/";, > "role": "primary", > "auto-failover": true > }, > { > "name": "kea04", > "url": "http://5.6.7.8:8080/";, > "role": "secondary", > "auto-failover": true > } > ] > } > ] > > - we configured the lease database like this for connecting to the > database cluster : > > "lease-database": { > "type": "mysql", > "name": "kea", > "user": "KEA_USER", > "password": "KEA_PASSWORD", > "host": "1.1.1.1", > "max-reconnect-tries" : 10, > "reconnect-wait-time" : 30000 > }, > > - we tried to connect to the database backend : > - through a VIP with load balancing > - through HAPROXY with / without load balancing > - > > When we start KEA service and the servers start, KEA logs show a lot of > DATABASE_MYSQL_FATAL_ERROR messages like this : > > 2025-01-07 16:18:42.483 ERROR [kea-dhcp4.database/4349.0x34cf8b308500] > DATABASE_MYSQL_FATAL_ERROR Unrecoverable MySQL error occurred: unable to > execute for <SELECT h.host_id, h.dhcp_identifier, h.dhcp_identifier_type, > h.dhcp4_subnet_id, h.dhcp6_subnet_id, h.ipv4_address, h.hostname, > h.dhcp4_client_classes, h.dhcp6_client_classes, h.user_context, > h.dhcp4_next_server, h.dhcp4_server_hostname, h.dhcp4_boot_file_name, > h.auth_key, o.option_id, o.code, o.value, o.formatted_value, o.space, > o.persistent, o.cancelled, o.user_context FROM hosts AS h LEFT JOIN > dhcp4_options AS o ON h.host_id = o.host_id WHERE h.dhcp4_subnet_id = ? AND > h.dhcp_identifier_type = ? AND h.dhcp_identifier = ? ORDER BY h.host_id, > o.option_id>, reason: Server has gone away (error code: 2006). > 2025-01-07 16:18:43.533 INFO [kea-dhcp4.dhcp4/4349.0x34cf8aa12000] > DHCP4_DB_RECONNECT_LOST_CONNECTION database connection lost. > 2025-01-07 16:18:43.533 INFO [kea-dhcp4.hosts/4349.0x34cf8aa12000] > DHCPSRV_MYSQL_HOST_DB opening MySQL hosts database: host=10.194.50.12 > max-reconnect-tries=10 name=prod_kea password=***** > reconnect-wait-time=30000 type=mysql universe=4 user=keaCluster > 2025-01-07 16:18:43.586 INFO [kea-dhcp4.dhcp4/4349.0x34cf8aa12000] > DHCP4_DB_RECONNECT_SUCCEEDED database connection recovered. > > As we noticed that the database connection is frequently lost for no > apparent reason we suspect that there is an issue with using persistent > database connections through a VIP with load balancing (maybe related to > multithreading also) > > Has anyone successfully configured such a setup ? How ? > What do you suggest for avoiding this error message and configuring a high > availability DHCP cluster with a high availability database cluster ? > > Any feedback from the community will be appreciated ! > Kind regards > > > > -- > > [image: Inline-Bild 1] > > *Sébastien NAUER <sna...@hotcity.lu>*| Technical Manager > 11, Avenue Guillaume | L-1651 Luxembourg <http://goo.gl/maps/GqQcf> > Phone: (+352) 2663 2660 | Fax: (+352) 2663 2665 > Facebook <https://www.facebook.com/hotcity.lu> | Twitter > <https://twitter.com/hotcity_wifi> > -- > ISC funds the development of this software with paid support > subscriptions. Contact us at https://www.isc.org/contact/ for more > information. > > To unsubscribe visit https://lists.isc.org/mailman/listinfo/kea-users. > > Kea-users mailing list > Kea-users@lists.isc.org > https://lists.isc.org/mailman/listinfo/kea-users >
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