[ovs-dev] [patch_v4] vtep: add source node replication support.

[Darrell Ball]

Offline discussion is documented in v1->v2 below.
There are various considerations to what kind of replication
configuration is needed and what is "better" varies with the
specific requirements. Feel free to suggest otherwise.

This patch series updates the vtep schema to support source node
replication in addition to service node replication per logical switch.
The default replication mode is service_node as that was the only
mode previously supported. 

New vtep-ctl commands are added to set/reset the replication
mode per logical switch.  Setting the replication mode is optional
and if no configuration is done, the replication mode is service node.
Resetting the replication mode sets the replication mode back to a
default of service node.
In the event that a physical switch cannot support source node 
replication,  an error is populated in the database that can be read
by a controller requesting source node replication mode. All logical
switches continue to use service node replication since source node
replication cannot be supported. If the controller then resets the
replication mode, the physical switch should clear the error state.

The vtep emulator is also updated to read the vtep database
logical switch replication mode and to support both types of replication.
The vtep emulator help documentation is also updated.


v1->v2: Offline discussion
In this discussion, it was agreed only logical switch level
replication mode configuration is needed.  The rational
was that physical switch level option configuration was only
added as a convenience; using a controller, the added
benefit is minimal and hence the physical switch level
configuration portion is dropped and the logical switch
level configuration retained.

Although in v1, service node mode is the default replication mode,
v2 makes replication mode an option and only source node mode
can be optionally configured. 

If a physical switch cannot support source node replication, then an
error should be set in the physical switch table that can be read by a
controller.

v2->v3: Fixed a couple bugs in ovs-vtep I noticed after v2.

v3->v4: 
Added recommendation text for handling lack of source node
replication mode support on a transport node in a logical switch, with
input from Bruce and Anupam (offline); added to vtep.xml.
Also added recommendation for proactive source node replication
mode support. 

Reworded alternate replication mode description in vtep.xml per
Bruce.  

Shorten name to Alternate Replication Mode from per logical switch
Alternate Replication Mode.

Darrell Ball (1):
  vtep: add source node replication support.

 tests/vtep-ctl.at       | 17 ++++++++++++++
 vtep/README.ovs-vtep.md | 19 ++++++++++++++--
 vtep/ovs-vtep           | 36 +++++++++++++++++++++++++----
 vtep/vtep-ctl.8.in      |  9 ++++++++
 vtep/vtep-ctl.c         | 42 ++++++++++++++++++++++++++++++++++
 vtep/vtep.ovsschema     |  9 ++++++--
 vtep/vtep.xml           | 60 ++++++++++++++++++++++++++++++++++++++++++++-----
 7 files changed, 179 insertions(+), 13 deletions(-)

-- 
1.9.1