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

[Alexander Bokovoy]

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.

-- 
/ Alexander Bokovoy