Comment 68 for bug 1583566

Reviewed: https://review.opencontrail.org/22047
Committed: http://github.org/Juniper/contrail-controller/commit/3661c074d691e8b979a90f2925fb05ebf2f2e160
Submitter: Zuul
Branch: R2.22.x

commit 3661c074d691e8b979a90f2925fb05ebf2f2e160
Author: Nipa Kumar <email address hidden>
Date: Mon May 23 16:42:13 2016 -0700

Send DNS records to named in batches instead of bulk send.

DNS record send and retries to named are done in a burst and does not succeed when it
reaches named limit of handling DNS update rates.

DNS records are now bunched in group sizes equivalent to hardware threads
and sent at periodical intervals (default = 1000msec).
DNS Update Rate = No of Hardware Threads/sec
DNS Update Rate is maintained constant.

o Added introspect command to Snh_ShowBindPendingList to show list of pending records
that have failed the configurable number of retries.
o Added end-of-config from IfMapServer to indicate sync to oper DB and initiate
writes to contrail-named.
o New config knobs are added to tune DNS Record send to named
o DEFAULT.named_max_retransmissions - Maximum number of retries to send records to named
( default set to 12 retries)
o DEFAULT.named_retransmission_interval - Retransmission interval in msec
( default set to 1sec)
o Also DEFAULT.named_max_cache_size is set to 32M as this is purely for caching queries.

Change-Id: I9f23f9d2208fbd8dfd92e0ad737762ed50d762ba
Closes-Bug:1583566
Closes-Bug:1574454

vDNS limits to 64k pending records.

o Implement lo and hi watermark to allow draining of vDNS records.
Default hi water-mark=32k and low water-mark=8k
o Use bitset vector to keep tab of allocated DNS transaction ids.

Change-Id: Iaf1520685dde627670a5b5f25dba1679be80385c
Closes-Bug:1593895