[Kea-users] HA survivor not taking over avec after communication interrupted with partner

[Alexandre Lessard]

I made a mistake, none of the networks recover from the server1 outage.

Le lun. 9 oct. 2023 à 13:37, Alexandre Lessard
<alex at targointernet.com> a écrit :
>
> Hello everyone,
>
> I'm new here! I'm working for an ISP as a network administrator.
> Furthermore, I got about 7 years of experience doing all sort of IT
> stuff for this company. I've been using and configuring Kea DHCP for
> about 2 weeks now. Prior to that, I was using ISC DHCP, but since it's
> now deprecated, I'm preparing two new servers to migrate all customers
> on them.
>
> The setup:
> The setup is DHCP relay with two Kea servers in HA hot-standby. There
> is three particularity that I want to mention right now.
>
> First, because I couldn't find an out-of-the-box solution, I made a
> script that replicate the configuration through the API on both server
> when they are restarted. I don't think it interferes with the service
> as it is run prior to the service startup, but I don't want to
> overlook it either.
>
> Second, they both have an IP configured on their loop back interface
> to be use kind of like an any cast address. That being said, I don't
> use them for the HA, it's only used by the Relay agents.
>
> Third, they are Proxmox containers. I don't think it's problematic but
> tell me if I'm wrong, I will make VMs for them.
>
> My problem:
> When I simulated an outage by stopping the server1, only 2 (test2 and
> test3) of the 4 subnets recover eventually. Even if they recover, it
> takes about 5 minutes. As much as I understand, it's supposed to be
> configured at 1 minute. The two other subnets never recovers.
> Why some subnets never recover?
> Why the 2 that recover take so long?
>
> I observed that the state of server2 stays to "hot-standby" even if
> the remote communication is interrupted.
>
> I have been working on fixing that for more than 10 hours now.
> Likewise, I really don't know what to look for anymore.
>
> The config:
> The Control Agents have almost default configuration, except for the
> http-host that is set to the IP interface that receive the request
> (eth0).
>
> The Dhcp6 server is disabled.
>
> Has for the Dhcp4 config, it has been saved through the API, so it is
> massive! All default configs have been written in the config file. For
> this reason, I won't post it here if not required to avoid sending a
> wall of config. I've put it on a public repository of GitHub:
> https://github.com/AlexTargo/Kea-Dhcp
>
> If I'm missing anything, let me know, and I'll share it as soon as possible.
>
> I hope someone have good pointers for me.
>
> Regards
> Alex