[Kea-users] Load-Balancing Network issue between Relay and Kea

[Mathias Aichinger]

Thank you for your answers.

Unfortunately it's not increasing the unacked packets and I have many log outputs with following:

2023-01-04 17:29:04.289 DEBUG [kea-dhcp4.ha-hooks/1427854.139856620329408] HA_BUFFER4_RECEIVE_NOT_FOR_US [hwtype=1], cid=[], tid=0x4036b3d: dropping query to be processed by another server

But these packets cannot be processed by the other server because I'm dropping them for testing purposes.

Maybe somebody from the KEA team can clarify?

Best Regards,


> On 02.01.2023, at 15:50, Frey, Rick E <Rick.Frey at windstream.com> wrote:
> 
> I’ve only used Kea in Hot-Standby configuration so I don’t have direct experience with Load-Balancing config but failover is similar. 
>  
> Docs indicate that your Kea 2 host should mark Kea 1 as “partner-down” state if number of un-ack’d clients is exceeded ( 1 in your configuration ).  In order for Kea 2 to detect the un-ack’d requests (that should be handled by Kea 1), the secs (Seconds elaspsed) field must exceed max-ack-delay value ( 10 seconds in your case ). 
>  
> Do your DHCP request include the secs field and exceed 10 seconds in your tests?
> Does “Kea 2” show any unacked-clients during your test/network disruption? 
> (status-get cmd will show unacked-clients as well as current state).
>  
>  
> From: Kea-users <kea-users-bounces at lists.isc.org <mailto:kea-users-bounces at lists.isc.org>> on behalf of Mathias Aichinger <mathias.aichinger at easysol.at <mailto:mathias.aichinger at easysol.at>>
> Date: Sunday, January 1, 2023 at 6:11 PM
> To: kea-users at lists.isc.org <mailto:kea-users at lists.isc.org> <kea-users at lists.isc.org <mailto:kea-users at lists.isc.org>>
> Subject: [Kea-users] Load-Balancing Network issue between Relay and Kea
> 
> CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.
>  
> Hi,
> 
> I currently playing around with the HA and load balancing and I one question appeared:
> 
> Scenario:
> 
> Multiple DHCP-Relays at different sites with both KEA-Servers as DHCP-Servers. Both servers are available and the load balancing shifts the requests between the two servers.
> 
> Incident: Because of a network issue Kea 1 is not available from the clients. The network connection between Kea 1 and Kea 2 still works, so no partner-down state.
> 
> Expected behaviour: Kea 2 sees the unacked clients of Kea 1 and sets Kea 1 in partner-down state and handles all requests.
> 
> Experienced behaviour: Kea 2 still reports HA_BUFFER4_RECEIVE_NOT_FOR_US and does not handle the requests
> 
> Is there a misunderstanding or configuration mistake on my side?
> 
> {
>          "library": "/usr/local/lib/kea//hooks/libdhcp_ha.so",
>          "parameters": {
>            "high-availability": [
>              {
>                "this-server-name": "server2",
>                "mode": "load-balancing",
>                "heartbeat-delay": 10000,
>                "max-response-delay": 60000,
>                "max-ack-delay": 10000,
>                "max-unacked-clients": 1,
>                "delayed-updates-limit": 100,
>                "peers": [
>                  {
>                    "name": "server1",
>                    "url": "http://192.168.248.1:8080/ <https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2F192.168.248.1%3A8080%2F&data=05%7C01%7Crick.frey%40windstream.com%7C03e10dc7ee6b44bf8b9508daec55f3c2%7C2567b4c1b0ed40f5aee358d7c5f3e2b2%7C0%7C0%7C638082151158318762%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=jpDZewyvQFVTEdrLMhapcgClTcerL8gfvZKK8qYeQhc%3D&reserved=0>",
>                    "role": "primary",
>                    "auto-failover": true
>                  },
>                  {
>                    "name": "server2",
>                    "url": "http://192.168.248.2:8080/ <https://nam02.safelinks.protection.outlook.com/?url=http%3A%2F%2F192.168.248.2%3A8080%2F&data=05%7C01%7Crick.frey%40windstream.com%7C03e10dc7ee6b44bf8b9508daec55f3c2%7C2567b4c1b0ed40f5aee358d7c5f3e2b2%7C0%7C0%7C638082151158318762%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=Ck5xI%2B4nn6huIG9KIG2VfLItqyHWlZCbrAgKdx%2F7Nxs%3D&reserved=0>",
>                    "role": "secondary",
>                    "auto-failover": true
>                  }
>                ]
>              }
>            ]
>          }
>        }
> 
> Thank you,
> 
> Mathias
>  
> 
> Sensitivity: Internal
> 

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