[Kea-users] [EXTERNAL] Kea fail start after power outage, mysql connect problem

[Wagner Vlastimil - HZS Ústeckého kraje]

I made in systemd service:
   
ExecStartPre=/bin/bash -c "until host db.example.com; do sleep 1; done"

but i thought that Kea have solution

VW

On Út, 2024-10-29 at 12:23 +0000, Geist, Dan (CCI-Atlanta) via Kea-users wrote:
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> Have you considered putting in a “watchdog” timer at the operating system level to restart the OS after a number of minutes (if network link is down) to allow your network gear more time to recover?
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> From:Kea-users <kea-users-bounces at lists.isc.org> on behalf of Wagner Vlastimil - HZS Ústeckého kraje <Vlastimil.Wagner at hzscr.cz>
> Date: Tuesday, October 29, 2024 at 8:00 AM
> To: kea-users at lists.isc.org <kea-users at lists.isc.org>
> Subject: [EXTERNAL] [Kea-users] Kea fail start after power outage, mysql connect problem
> 
> 
> Hi
> 
> I have Kea servers on places where sometimes doesnt work power (longer than UPS) 
> I have config, leases and hosts in database MySQL
> When power is back server get up faster than switches and routers so interface is down and Kea doesnt start
> 
> říj 29 12:42:15 dhcp-01.hzsulk.cz kea-dhcp4[8647]: ERROR [kea-dhcp4.dhcp4.140105088432256] DHCP4_CONFIG_LOAD_FAIL configuration error using file: /etc/kea/kea-dhcp4.conf, reason: during update from
> config backend database: Unknown server host 'db.example.com' (-2)  
> říj 29 12:42:15 dhcp-01.hzsulk.cz kea-dhcp4[8647]: ERROR [kea-dhcp4.dhcp4.140105088432256] DHCP4_INIT_FAIL failed to initialize Kea server: configuration error using file '/etc/kea/kea-dhcp4.conf':
> during update from config backend database: Unknown server host 'db.example.com' >  
> říj 29 12:42:15 dhcp-01.hzsulk.cz kea-dhcp4[8647]: ERROR [kea-dhcp4.dhcp4.140105088432256] DHCP4_PARSER_COMMIT_FAIL parser failed to commit changes: during update from config backend database:
> Unknown server host 'db.example.com' (-2) 
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> 
> Config is:
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> "Dhcp4": {
>     "server-tag": "DHCP-01",
>     "interfaces-config": {
>         "interfaces": ["ens33"],
>         "service-sockets-max-retries": 100,
>         "service-sockets-retry-wait-time": 5000
>     },
>     "config-control": {
>         "config-databases": [{
>                 "type": "mysql",
>                 "name": "kea",
>                 "user": "kea",
>                 "password": "fhgfethfgthtfeg",
>                 "host": "db.example.com",
>                 "port": 3306,
> #               "retry-on-startup": "true",
>                 "max-reconnect-tries" : 30000,
>                 "reconnect-wait-time": 3000
>             }],
>         "config-fetch-wait-time": 20
>     },
> 
> No setting work to try connect again
> 
> 
> VW