Failover strangeness

[Glenn Satchell]

>Date: Mon, 16 Oct 2006 09:23:58 -0400
>From: Greg G <ggersh at ctc.net>
>To: dhcp-users at isc.org
>Subject: Re: Failover strangeness
>
>Glenn Satchell wrote:
>>>   The secondary dhcp server is down, but the running server is still 
>>> showing as being in communications-interrupted.  It never gets to 
>>> partner-down.
>>>     
>>
>> Ahh, didn't realise the second server was down. partner-down mode must
>> be set manually. There is one method described in the dhcpd.conf man
>> page, by editting the leases file.
>>
>> It can also be done using omshell. This is from a posting to the list
>> in June this year.
>>
>> Here's the interactive version.
>>
>>   
>   Thanks.  It would be extremely helpful if this information was in the 
>man page or a doc somewhere.

You could always write a patch for the man page(s) and submit it. David
Hankins mentioned a little while ago that he can integrate
documentation updates very easily.

>>> set name = "<failovername>"   - the quotes are required here!
>>>     
>   *Especially* this bit of information.
>
>>> set local-state = 00:00:00:01
>>>     
>   And this.  Although I probably would have guess at the format from 
>the info dump, it's not intuitive that this isn't just a number.

Yes, but a few simple experiments were all that was required to work
this out. There's a few examples in the omshell man page that display
the data in this format so I copied from those.

>   I guess the frustrating part of this is that I have to take this 
>manual action for the failover to work correctly.  That's problematic.

I don't have it with me at the moment, but I wrote a simple shell
script that ran on the primary server. If it couldn't ping the other
server for 10 minutes or so then it switched the local server to
partner down mode using the above logic. If you think this would be
useful I can dig it out next week and then post it, but the logic is
very simple to implement.

regards,
-glenn
--
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