cluster.go: Disable Southbound DB conditional monitoring.

ovn-controller enables conditional monitoring by default for tables in
the Southbound Database it is interested in (e.g., Logical_Flow). This
effectively performs row level filtering for the SB DB tables such that
an ovn-controller would receive only updates about records that refer to
logical datapaths that are local to the chassis.

However, in an ovn-kubernetes cluster, all node logical switches are
connected to the ovn-cluster-router which forces all ovn-controllers to
register for updates about all logical switches.

The conditional monitoring implementation in OVSDB turns out to not
scale so well in such scenarios.

OVN 20.03 supports a new configuration knob (ovn-monitor-all=true) which
instructs ovn-controllers to not use row level filtering of records.
This was introduced by:
ovn-org/ovn@3c355e3

ovn-kubernetes per node gateway routers are bound to individual chassis
and should not generate openflow entries on other chassis. This is also
handled in OVN 20.03 by follow up commits:
ovn-org/ovn@166a33c
ovn-org/ovn@eebef50

Note regarding backwards compatibility:
When ovn-kubernetes is used with older OVN versions (i.e., <20.03)
setting "ovn-monitor-all=true" has no effect as the knob will just be
ignored by ovn-controller.

Reported-by: Girish Moodalbail <[email protected]>
Reported-at: https://groups.google.com/d/msg/ovn-kubernetes/OalZ5-2ljnA/FOGlAyK5DQAJ
Signed-off-by: Dumitru Ceara <[email protected]>

go-controller/pkg/cluster/cluster.go

@@ -57,6 +57,7 @@ func setupOVNNode(node *kapi.Node) error {
 		fmt.Sprintf("external_ids:ovn-openflow-probe-interval=%d",
 			config.Default.OpenFlowProbe),
 		fmt.Sprintf("external_ids:hostname=\"%s\"", nodeName),
+		"external_ids:ovn-monitor-all=true",
 	)
 	if err != nil {
 		return fmt.Errorf("error setting OVS external IDs: %v\n  %q", err, stderr)

go-controller/pkg/cluster/node_test.go

@@ -59,7 +59,8 @@ var _ = Describe("Node Operations", func() {
 					"external_ids:ovn-encap-ip=%s "+
 					"external_ids:ovn-remote-probe-interval=%d "+
 					"external_ids:ovn-openflow-probe-interval=%d "+
-					"external_ids:hostname=\"%s\"",
+					"external_ids:hostname=\"%s\" "+
+					"external_ids:ovn-monitor-all=true",
 					nodeIP, interval, ofintval, nodeName),
 			})
 
@@ -112,7 +113,8 @@ var _ = Describe("Node Operations", func() {
 					"external_ids:ovn-encap-ip=%s "+
 					"external_ids:ovn-remote-probe-interval=%d "+
 					"external_ids:ovn-openflow-probe-interval=%d "+
-					"external_ids:hostname=\"%s\"",
+					"external_ids:hostname=\"%s\" "+
+					"external_ids:ovn-monitor-all=true",
 					nodeIP, interval, ofintval, nodeName),
 			})
 			fexec.AddFakeCmd(&ovntest.ExpectedCmd{