[Kea-users] execute scripts and kea

[Francis Dupont]

"Philippe Maechler" writes:
> We're currently using the ISC-DHCPD in our cable and ftth network. All
> the devices need a dedicated configuration file, which we generate either
> statically or dynamically with the execute statement.

=> note Kea allows dynamic configuration changes and structures
handling the current configuration are accessible from hooks
which run in the Kea process address space.

> Unfortunately when an access systems breaks, we have several hundred
> requests at the same time and the script, which generates the
> config-files
> takes a rather long time (~1-2 secs per cpe). During this time the whole
> dhcpd isn't handling out other leases

=> moving from scripts to C++ should solve this.

> Does kea have something like the execute statement?

=> no but it has an integrated extension mechanism with hooks.

> There is already a hook, which lets you run your own script (see New Kea
> hook to call external scripts: kea-hook-runscript)

=> it is more for scripts with an "external" action as adding a route.

> Tomek Mrugalski wrote: One thing you should consider in the future is
> that if the script takes a long time to execute, it will freeze whole
> Kea execution.

=> yes, hooks are synchronous (DHCP service is essentially sequential
because of resource assignement (*)).

> I hoped that KEA would be different and that the freeze would only
> affect the current client/mac address or the current transaction id

=> you hoped DHCP would be different... (:-)

> Is there a way around this limitation?

=> an easy one: run a server per shared network (or subnetwork if you have
no shared networks). Note this allows too to reuse the same (private)
address space too.

Thanks

Francis Dupont <fdupont at isc.org>