ovn: support requested-chassis option for logical switch ports

This patch adds support for a "requested-chassis" option for logical
switch ports. If set, the only chassis that will claim this port is the
chassis identfied by this option; if already bound by another chassis,
it will be released.

The primary benefit of this enhancement is allowing a CMS to prevent
"thrashing" in the southbound database during live migration by keeping
the original chassis from attempting to re-bind a port that is in the
process of migrating.

This would also allow (with some additional work) RBAC to be applied
to the Port_Binding table for additional security.

Signed-off-by: Lance Richardson <lrichard@redhat.com>
Signed-off-by: Russell Bryant <russell@ovn.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/ovn/ovn-sb.xml b/ovn/ovn-sb.xml
index 08d784ac6..7098194c6 100644
--- a/ovn/ovn-sb.xml
+++ b/ovn/ovn-sb.xml
@@ -2159,6 +2159,14 @@ tcp.flags = RST;
         (empty string)
       </p>
 
+      <column name="options" key="requested-chassis">
+        If set, identifies a specific chassis (by name) that is allowed to
+        bind this port. Using this option will prevent thrashing between
+        two chassis trying to bind the same port during a live migration.
+        It can also prevent similar thrashing due to a mis-configuration,
+        if a port is accidentally created on more than one chassis.
+      </column>
+
       <column name="options" key="qos_max_rate">
         If set, indicates the maximum rate for data sent from this interface,
         in bit/s. The traffic will be shaped according to this limit.