Upstream ticket:
https://fedorahosted.org/sssd/ticket/1476

Devel and Quality Engineering have reviewed this request and determined that it will be best solved by a more complete solution in a later release. We would rather see the value be configurable, rather than adjusting it to a different hard-coded value.

Please provide implementation details and use cases for this new configuration option.

(In reply to comment #9)
> Please provide implementation details and use cases for this new
> configuration option.

Set the ipa_dyndns_ttl option to a value in seconds. Update the client's addres using the dyndns functionality. Then view the DNS record on the server, in particular its TTL value. It should match the one provided with the config option.

Not sure what implementation details you are looking for, but there is nothing user visible apart from the single option.

Internally, what the option does is that its value is used as the TTL instead of the previously hardcoded value of 86400 seconds.

As the guy that originally reported this and wrote the patch ;-) 

Use case:
Hostname that changes IP more frequently than once per day... This could be a test VM being rebuilt (which is where I encountered this) or a laptop user moving between subnets.

How to use:
Set the option as mentioned above and as detailed in --help and the man page.

There was a corresponding patch to ipa-client-install on the freeipa-client side to configure this option on install but I don't think it was ever committed... It might be worth checking to avoid the edge case of the initial DNS update by ipa-client-install setting the TTL high (if memory serves though it was only something like 1200 seconds).

However that has no impact on the functionality of this in sssd 1.10

Thanks for the details, James, that's going to help our QE test the feature!

No problem... Apologies in not having more detail but I'm in a restaurant right now..

As one note though it's best to test the feature either looking straight at the IPA server with a utility like dig or to watch the 'fail' event the old host record still needs to be in a DNS cache somewhere on or between the system being used for the DNS query and the IPA server...

If there's any additional information useful I'll be able to respond tomorrow or Thursday.

Thank you James!

Temporarily moving bugs to MODIFIED to work around errata tool bug

Verified.

IPA version:
============
------------[RPMs & OS: [RedHat - x86_64]---------
|       ipa-client-3.3.3-15.el7.x86_64
|       sssd-1.11.2-19.el7.x86_64
--------------------------------------------------

Snippet from automation log:
===========================

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:: [   LOG    ] :: ipaclientinstall_bug_847716 The TTL value for FreeIPA dynamic DNS updates should be configurable bz847716
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

:: [   LOG    ] :: uninstall_fornexttest starts
:: [   LOG    ] :: sssd.conf for testing BZ 819982 does not exists
:: [   LOG    ] :: checking for '^nameserver 10.16.46.51' in /etc/resolv.conf
:: [   PASS   ] :: Running 'ssh root.46.51 "echo Secret123|kinit admin;ipa host-del amd-pike-05.testrelm.com"' (Expected 0,1,2, got 0)
:: [   PASS   ] :: Running 'sleep 60' (Expected 0, got 0)
:: [   LOG    ] :: uninstall_fornexttest ends
:: [   LOG    ] :: EXECUTING: ipa-client-install --domain=testrelm.com --realm=TESTRELM.COM -p admin -w Secret123 --unattended --server=hp-dl380pgen8-02-vm-2.testrelm.com --enable-dns-updates --mkhomedir
:: [   PASS   ] :: Installing ipa client and configuring - with all params (Expected 0, got 0)
:: [   LOG    ] :: execute expect file: /tmp/kinit.10792.exp
:: [   LOG    ] :: Success: kinit as [admin] with password [Secret123] was successful.
:: [   PASS   ] :: Kinit as admin user (Expected 0, got 0)
:: [   PASS   ] :: Capturing TTL value (Expected 0, got 0)
:: [   PASS   ] :: Running 'cat /tmp/bz847716.txt' (Expected 0, got 0)
:: [   PASS   ] :: File '/tmp/bz847716.txt' should contain 'Time to live: 1200' 
:: [   PASS   ] :: Assigning em1:0 with ip 192.168.0.1 (Expected 0, got 0)
:: [   PASS   ] :: Capturning ifconfig output (Expected 0, got 0)
:: [   PASS   ] :: Running 'cat /tmp/bz847716.txt' (Expected 0, got 0)
:: [   PASS   ] :: File '/tmp/bz847716.txt' should contain 'em1:0' 
:: [   PASS   ] :: File '/tmp/bz847716.txt' should contain '192.168.0.1' 
:: [   PASS   ] :: Running 'sed '/cache_credentials/ a debug_level = 0x200' /etc/sssd/sssd.conf > /tmp/sssd.conf' (Expected 0, got 0)
:: [   PASS   ] :: Running 'cp /tmp/sssd.conf /etc/sssd/sssd.conf' (Expected 0, got 0)
:: [   PASS   ] :: Running 'sed '/ipa_dyndns_update/ a ipa_dyndns_iface = em1:0' /etc/sssd/sssd.conf > /tmp/sssd.conf' (Expected 0, got 0)
:: [   PASS   ] :: Running 'cp /tmp/sssd.conf /etc/sssd/sssd.conf' (Expected 0, got 0)
:: [   PASS   ] :: Running 'cat /etc/sssd/sssd.conf' (Expected 0, got 0)
:: [   PASS   ] :: Capturing TTL value after ip change (Expected 0, got 0)
:: [   PASS   ] :: Running 'cat /tmp/bz847716.txt' (Expected 0, got 0)
:: [   PASS   ] :: File '/tmp/bz847716.txt' should contain 'Time to live: 1200' 
:: [   PASS   ] :: File '/tmp/bz847716.txt' should contain '192.168.0.1' 
:: [   PASS   ] :: Running 'rm -rf /tmp/bz847716.txt' (Expected 0, got 0)
:: [   LOG    ] :: Duration: 1m 17s
:: [   LOG    ] :: Assertions: 22 good, 0 bad
:: [   PASS   ] :: RESULT: ipaclientinstall_bug_847716 The TTL value for FreeIPA dynamic DNS updates should be configurable bz847716

This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.