NS issues

[Moti Levy]

I agree, dns caching is an issue with many apps , i can tell you that if
you have tomcat anywhere in that list you can forget about dns as a
failover mechanism.

I suggest you assign a "virtual ip" that can be moved ( either manually
or via keepalived or any other clustering tool ) when needed.


Andrew Bacchi wrote:
> In my case, the application client caches the server address internally.
>  Unless I flush this client cache it keeps trying to connect to the old
> IP address.  You may have a similar situation.
> 
> One possible solution is to reboot the standby machine with the IP
> address and hostname of the failed machine.  It's less work to do that
> than change DNS records.
> 
> Flynn, Neill wrote:
>> Hi all,
>>
>> I'm a Solaris admin who has a few RH boxes to look after. We use NIS
>> and DNS for name resolution. The NIS host file gets updated by hand
>> and the DNS server uses this information to create it's named DB's.
>> All clients are setup to use "files, NIS, DNS" in their nsswitch.conf.
>>
>> We have 3 boxes running propriety software (all on the same subnet),
>> two run in production and one is a backup. I created an alias for each
>> of the primary machines which is now used for accessing the services
>> on that box. "In the unlikely event of a failure", the plan is to
>> switch the alias from the faulty primary machine to the backup machine
>> and restart all services.
>>
>> During testing, I changed the alias and updated DNS (I had a wee
>> problem with the TTL for the DNS zone - as these machines actually use
>> a secondary DNS server - this was overcome and all seemed fine). When
>> the application support lads went to startup the application, it was
>> still trying the old IP address of the aliased hostname.
>>
>> I checked everything I could think of (mainly from a Solaris
>> perspective)…./etc/nsswitch.conf, /etc/resolv.conf, ypmatch, nslookup,
>> arp, nscd (which isn't running)……anyway I found nothing obvious. Can
>> anyone suggest anything else that I should look at?
>>
>> Thanks in advance for any help,
>> Neill
>>
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