[Dnsmasq-discuss] MAN Page Link Broken? and redundancy question

[richardvoigt at gmail.com]

On Fri, Sep 4, 2009 at 4:18 PM, Robert Boerner<robert.boerner at gmail.com> wrote:
> Hi Richard,
>
> Thanks for the quick response.
>
> I am in fact using a separate router as the gateway. I like the idea
> of splitting the pool, but that brings up a follow-on question...what
> about static reservations I have set? Can I simply have them on both?

AFAIK, yes.

>
> That also brings up yet another question...is it 'wrong' to have
> static reservations assigned to addresses that are within the normal
> scope? I know best practice is to have them designated outside, but I
> am trying to replace a Windows box in an environment where people have
> been assigning static reservations within the regular DHCP scope for
> years. I don't want to have to redo everything.

Some people may frown upon it, but my experience is that dnsmasq will
reserve any address corresponding to a static assignment and not give
it away to any other client.  So you should be fine.

Something simple (and nearly stateless) Simon could do to make this
use-case work a little better -- a configuration parameter
load-balancer k of N, where dnsmasq responds immediately if
hash(client address) % N == k and delays by a second otherwise.

That way instead of the fastest hardware always responding first and
running out of addresses, the clients would be more evenly spread
among the subpools and you'd have more runtime following a failure
before all clients get moved into (and exhaust) the surviving pool(s).

>
> Thanks again for the help.
>
> On Fri, Sep 4, 2009 at 12:23 PM,
> richardvoigt at gmail.com<richardvoigt at gmail.com> wrote:
>> On Fri, Sep 4, 2009 at 3:08 PM, Robert Boerner<robert.boerner at gmail.com> wrote:
>>> Hello,
>>>
>>> First, it appears (at least to me) that as of right now the link to
>>> the online version of the MAN page simply leads to a blank page
>>> (http://www.thekelleys.org.uk/dnsmasq/docs/dnsmasq-man.html). Can
>>> anyone else confirm?
>>
>> I have the same result (no content on that page).
>>
>>>
>>> Second, I tried looking through the mailing list and other pages but I
>>> have (what I hope) a simple question about configuring dnsmasq:
>>>
>>> I have the software running (very well I might add) on a Marvell
>>> Sheevaplug. I ideally would like to have two of these inexpensive
>>> devices running to provide redundancy. Is there a way to configure two
>>> concurrently running instances of dnsmasq (one each on a physically
>>> separate device) for the same DHCP scope so that if one instance fails
>>> the other takes over? I saw this can be done with the ISC DHCP daemon
>>> but I like dnsmasq better :-)
>>
>> You could split the address pool into two and configure half on each.
>> Then during normal operations there will be a race to offer an
>> address, the client will accept only one.  If one fails, the other
>> will continue offering addresses.  If one runs out of addresses, the
>> other continues to work fine.  The only problem would be if one fails
>> and the other runs out of addresses.
>>
>> Are you using the dnsmasq machines as the gateway, or another router?
>> That could become pretty important if you want redundancy (you
>> actually have to transfer the address of the failed unit).
>>
>>>
>>> Thanks in advance for any help and thanks for your work on this application.
>>>
>>> Bob Boerner
>>>
>>> _______________________________________________
>>> Dnsmasq-discuss mailing list
>>> Dnsmasq-discuss at lists.thekelleys.org.uk
>>> http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
>>>
>>
>
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