dhcp-users Digest, Vol 165, Issue 6

Fri Jul 15 14:26:58 UTC 2022

Ahh, so I'm not a unique snowflake. I did actually already separate out the
static host definitions into a separate file. My process for updating the
file (which is a somewhat frequent operation) is

   1. update one of the files
   2. test the config `dhcpd -t -cf dhcpd.conf`
   3. reload the daemon
   4. scp to the secondary
   5. reload the daemon
   6. hope that you don't miss any of these steps

Let's compare this to our friends running an active-directory integrated
built-in Windows DHCP server.

   1. They clickity click on a thing to add a new reservation.
   2. There is no step 2

I suppose my take-away is that this is not a user journey I should expect
dhcpd to be helpful with. If we're off in roll-your-own territory, I was
thinking that using Syncthing to keep the configs automatically in sync,
along with some manner of cron job or inotifywait to trigger the secondary
to reload would probably work fine. To me, this seems such a common
operational pattern that making everyone do their own dental work seems not
so terrific - but yes I can come up with something that can work better
than manual tomfoolery.

On Fri, Jul 15, 2022 at 8:05 AM <dhcp-users-request at lists.isc.org> wrote:

> Send dhcp-users mailing list submissions to
>         dhcp-users at lists.isc.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
>         https://lists.isc.org/mailman/listinfo/dhcp-users
> or, via email, send a message with subject or body 'help' to
>         dhcp-users-request at lists.isc.org
>
> You can reach the person managing the list at
>         dhcp-users-owner at lists.isc.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of dhcp-users digest..."
>
>
> Today's Topics:
>
>    1. Failover + Static host definitions (Ryan Shea)
>    2. Re: Failover + Static host definitions (Richard L. Hamilton)
>    3. Re: Failover + Static host definitions (Glenn Satchell)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 14 Jul 2022 10:51:04 -0400
> From: Ryan Shea <ryan at muppethouse.com>
> To: dhcp-users at lists.isc.org
> Subject: Failover + Static host definitions
> Message-ID:
>         <CAL6QW496AknMABKu2874L=MSWvWp_Q9THoUm8QLQnnOjPhO=
> TQ at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Failover of a pool seems straightforward enough - however this is
> insufficient in the case where static reservations are present in host
> definitions. I am looking for some solution by which I have a redundant
> pair of dhcpd services which can not only fail over leases from a pool, but
> also keep those hosts with static reservations working.
>
> Is this as simple as synchronizing the host config definitions and running
> both services - without any particular concern about which server replies?
> Manually managing host configs for reservations in two places seems
> sub-optimal.
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> https://lists.isc.org/pipermail/dhcp-users/attachments/20220714/12157430/attachment-0001.htm
> >
>
> ------------------------------
>
> Message: 2
> Date: Thu, 14 Jul 2022 11:22:13 -0400
> From: "Richard L. Hamilton" <rlhamil at smart.net>
> To: Users of ISC DHCP <dhcp-users at lists.isc.org>
> Subject: Re: Failover + Static host definitions
> Message-ID: <29780D6E-64C1-47CE-9D5C-6094F46B04E1 at smart.net>
> Content-Type: text/plain;       charset=utf-8
>
> I have failover set up, and while I have a dynamic range, all known
> devices have static reservations configured.
>
> Except for what has to be different between primary and secondary, the
> configuration files are the same; they both have the same host definitions.
>
> Separating the configuration file into two parts: the main part with the
> primary or secondary information and pool definitions, which then includes
> on both an identical copy of  the file with the static host information,
> seems like it would simplify matters; you?d only be editing one file and
> copying it (and restarting both DHCP servers, presumably). Or you could
> script something really kewl with omshell to do both maybe, but if you make
> a mistake, you mess up both at the same time. At least if you?re editing a
> file, you can make sure the primary is behaving after restarting it before
> copying the edited file over to the secondary and restarting it too.
>
> Putting the included file on a share that both can access would NOT be as
> good as it sounds, since that?s one more thing that has to be up in the
> right order, and could break.
>
> > On Jul 14, 2022, at 10:51 AM, Ryan Shea <ryan at muppethouse.com> wrote:
> >
> > Failover of a pool seems straightforward enough - however this is
> insufficient in the case where static reservations are present in host
> definitions. I am looking for some solution by which I have a redundant
> pair of dhcpd services which can not only fail over leases from a pool, but
> also keep those hosts with static reservations working.
> >
> > Is this as simple as synchronizing the host config definitions and
> running both services - without any particular concern about which server
> replies? Manually managing host configs for reservations in two places
> seems sub-optimal.
> > --
> > ISC funds the development of this software with paid support
> subscriptions. Contact us at https://www.isc.org/contact/ for more
> information.
> >
> > dhcp-users mailing list
> > dhcp-users at lists.isc.org
> > https://lists.isc.org/mailman/listinfo/dhcp-users
>
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 15 Jul 2022 11:04:26 +1000
> From: Glenn Satchell <glenn.satchell at uniq.com.au>
> To: Users of ISC DHCP <dhcp-users at lists.isc.org>
> Subject: Re: Failover + Static host definitions
> Message-ID: <305edd76-55db-4ca5-9945-8238ea7449da at email.android.com>
> Content-Type: text/plain; charset="us-ascii"
>
> An HTML attachment was scrubbed...
> URL: <
> https://lists.isc.org/pipermail/dhcp-users/attachments/20220715/6852c278/attachment-0001.htm
> >
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> ISC funds the development of this software with paid support
> subscriptions. Contact us at https://www.isc.org/contact/ for more
> information.
>
> dhcp-users mailing list
> dhcp-users at lists.isc.org
> https://lists.isc.org/mailman/listinfo/dhcp-users
>
>
> ------------------------------
>
> End of dhcp-users Digest, Vol 165, Issue 6
> ******************************************
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/dhcp-users/attachments/20220715/2cb954db/attachment.htm>