In some specific use case, the cloud operator expects the source port
of a packet to stay the same across all masquerading layer up to the
destination host. With the implementation of the random-fully code,
this behavior was changed as source_port is always rewritten no matter
which type of architecture / network CIDRs is being used in the backend.
This setting allows a user to fallback to the original behavior of the
masquerading process which is to keep the source_port consistent across
all layers. The initial random-fully fix prevents packet drops when
duplicate tuples are generated from two different namespace when the
source_ip:source_port goes toward the same destination so enabling this
setting would allow this issue to show again. Perhaps a right approach
here would be to fix this "racey" situation in the kernel by perhaps
using the mac address as a seed to the tuple ...
Change-Id: Idfe5e51007b9a3eaa48779cd01edbca2f586eee5
Closes-bug: #1987396
bbefe5285e