[Freeipa-users] Correct *usage* for round-robin DNS srv records

[Mark Heslin]

Hi Alexander,

 >SRV records need to be resolved first by your software and then resolved
 >records used to perform lookups of the SRV entry content.

Ah, yes that explain it.

 >If your clients don't know how to do that, you  can use multiple A/AAAA
 >record entries to allow round-robin them.

The funny thing here is that this is how I initially configured this (A 
Recs) but it was suggested
that I use srv records. Since the OpenShift client do not make use of 
srv records then I'll go back
to my initial configuration with A records.

At least now I understand srv records better and this will be used more 
and more in the future:-)

Thank you all!

-m


On 07/23/2014 10:11 AM, Alexander Bokovoy wrote:
> On Wed, 23 Jul 2014, Mark Heslin wrote:
>> Martin, Petr,
>>
>> Thanks for helping me sort through the syntax. I have the entries 
>> added properly:
>>
>>  # ipa dnsrecord-show example.com _foo.tcp
>>    Record name: _foo.tcp
>>    SRV record: 0 0 53 foo1.example.com., 0 0 53 foo2.example.com.
>>
>>  # host -t srv _foo.tcp
>>  _foo.tcp.example.com has SRV record 0 0 53 foo2.example.com.
>>  _foo.tcp.example.com has SRV record 0 0 53 foo1.example.com.
>>
>> but how to I actually use the entry?
> You are already using it above with host command.
>
>>
>> # nslookup _foo.tcp
>> Server:        10.19.140.101
>> Address:    10.19.140.101#53
>>
>> *** Can't find _foo.tcp: No answer
>>
>> # nslookup _foo.tcp.example.com.
>> Server:        10.19.140.101
>> Address:    10.19.140.101#53
>>
>> *** Can't find _foo.tcp.example.com.: No answer
> This is SRV record, so you need to tell nslookup to look up SRV record,
> not A or CNAME as it does by default.
>
>>
>> # ping _foo.tcp
>> ping: unknown host _foo.tcp
> SRV records need to be resolved first by your software and then resolved
> records used to perform lookups of the SRV entry content.
> http://en.wikipedia.org/wiki/SRV_record
>
>>
>> The point of this is to create a front-end to balance requests from 
>> OpenShift clients
>> across a set of OpenShift brokers. Host "foo" would alternate across 
>> the first broker
>> (foo1) and second broker (foo2).
> Then OpenShift clients (software) need to know how to resolve SRV 
> record prior to
> connecting to the host that is pointed by the record.
>
> If your clients don't know how to do that, you  can use multiple A/AAAA
> record entries to allow round-robin them.
>


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