northd: Allow backwards compatibility for Logical_Switch_Port.up.

In general, ovn-northd expects ovn-controller to set Port_Binding.up
before it declares the logical switch port as being up.

Even though the recommended upgrade procedure for OVN states that
ovn-controllers should be upgraded before ovn-northd, there are cases
when CMSs don't follow this guideline.

This would cause all existing and bound Logical_Switch_Ports to be
declared "down" until ovn-controllers are upgraded.

To avoid this situation, ovn-controllers now explicitly set
Chassis.other_config:port-up-notif in their own chassis record.  Based
on this value, ovn-northd can determine if it needs to use the old type
of logic or the new one (Port_Binding.up) when setting LSP.up.

Note:
In case of downgrading ovn-controller before ovn-northd, if
ovn-controller is forcefully stopped it will not clear its chassis
record from the SB. Older versions will not have the capability to
clear the other_config:port-up-notif value so LSPs will be declared
"down" until ovn-northd is downgraded as well.  As this
upgrade/downgrade procedure is not the recommended one, we don't try
to deal with this scenario.

Signed-off-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: Numan Siddique <numans@ovn.org>

controller/chassis.c

@@ -28,6 +28,7 @@
 #include "lib/ovn-sb-idl.h"
 #include "ovn-controller.h"
 #include "lib/util.h"
+#include "ovn/features.h"
 
 VLOG_DEFINE_THIS_MODULE(chassis);
 
@@ -293,6 +294,7 @@ chassis_build_other_config(struct smap *config, const char *bridge_mappings,
     smap_replace(config, "iface-types", iface_types);
     smap_replace(config, "ovn-chassis-mac-mappings", chassis_macs);
     smap_replace(config, "is-interconn", is_interconn ? "true" : "false");
+    smap_replace(config, OVN_FEATURE_PORT_UP_NOTIF, "true");
 }
 
 /*
@@ -363,6 +365,11 @@ chassis_other_config_changed(const char *bridge_mappings,
         return true;
     }
 
+    if (!smap_get_bool(&chassis_rec->other_config, OVN_FEATURE_PORT_UP_NOTIF,
+                       false)) {
+        return true;
+    }
+
     return false;
 }
 

include/ovn/automake.mk

@@ -2,5 +2,6 @@ ovnincludedir = $(includedir)/ovn
 ovninclude_HEADERS = \
 	include/ovn/actions.h \
 	include/ovn/expr.h \
+	include/ovn/features.h \
 	include/ovn/lex.h  \
 	include/ovn/logical-fields.h

include/ovn/features.h

@@ -0,0 +1,22 @@
+/* Copyright (c) 2021, Red Hat, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef OVN_FEATURES_H
+#define OVN_FEATURES_H 1
+
+/* ovn-controller supported feature names. */
+#define OVN_FEATURE_PORT_UP_NOTIF "port-up-notif"
+
+#endif

northd/ovn-northd.c

@@ -40,6 +40,7 @@
 #include "lib/lb.h"
 #include "memory.h"
 #include "ovn/actions.h"
+#include "ovn/features.h"
 #include "ovn/logical-fields.h"
 #include "packets.h"
 #include "openvswitch/poll-loop.h"
@@ -12838,7 +12839,17 @@ handle_port_binding_changes(struct northd_context *ctx, struct hmap *ports,
             continue;
         }
 
-        bool up = ((sb->up && (*sb->up)) || lsp_is_router(op->nbsp));
+        bool up = false;
+
+        if (lsp_is_router(op->nbsp)) {
+            up = true;
+        } else if (sb->chassis) {
+            up = smap_get_bool(&sb->chassis->other_config,
+                               OVN_FEATURE_PORT_UP_NOTIF, false)
+                 ? sb->n_up && sb->up[0]
+                 : true;
+        }
+
         if (!op->nbsp->up || *op->nbsp->up != up) {
             nbrec_logical_switch_port_set_up(op->nbsp, &up, 1);
         }

ovn-sb.xml

@@ -322,6 +322,11 @@
       table. See <code>ovn-controller</code>(8) for more information.
     </column>
 
+    <column name="other_config" key="port-up-notif">
+      <code>ovn-controller</code> populates this key with <code>true</code>
+      when it supports <code>Port_Binding.up</code>.
+    </column>
+
     <group title="Common Columns">
       The overall purpose of these columns is described under <code>Common
       Columns</code> at the beginning of this document.

tests/ovn-controller.at

@@ -414,3 +414,20 @@ OVS_WAIT_UNTIL([ovs-vsctl get Bridge br-int external_ids:ovn-nb-cfg], [0], [1])
 
 OVN_CLEANUP([hv1])
 AT_CLEANUP
+
+AT_SETUP([ovn -- features])
+AT_KEYWORDS([features])
+ovn_start
+
+net_add n1
+sim_add hv1
+ovs-vsctl add-br br-phys
+ovn_attach n1 br-phys 192.168.0.1
+
+# Wait for ovn-controller to register in the SB.
+OVS_WAIT_UNTIL([
+    test "$(ovn-sbctl get chassis hv1 other_config:port-up-notif)" = '"true"'
+])
+
+OVN_CLEANUP([hv1])
+AT_CLEANUP

tests/ovn-northd.at

@@ -2421,3 +2421,25 @@ check ovn-nbctl --wait=sb sync
 AT_CHECK([grep -qE 'duplicate logical.*port p1' northd/ovn-northd.log], [0])
 
 AT_CLEANUP
+
+AT_SETUP([ovn -- Port_Binding.up backwards compatibility])
+ovn_start
+
+ovn-nbctl ls-add ls1
+ovn-nbctl --wait=sb lsp-add ls1 lsp1
+
+# Simulate the fact that lsp1 had been previously bound on hv1 by an
+# ovn-controller running an older version.
+ovn-sbctl \
+    --id=@e create encap chassis_name=hv1 ip="192.168.0.1" type="geneve" \
+    -- --id=@c create chassis name=hv1 encaps=@e \
+    -- set Port_Binding lsp1 chassis=@c
+
+wait_for_ports_up lsp1
+
+# Simulate the fact that hv1 is aware of Port_Binding.up, ovn-northd
+# should transition the port state to down.
+check ovn-sbctl set chassis hv1 other_config:port-up-notif=true
+wait_row_count nb:Logical_Switch_Port 1 up=false name=lsp1
+
+AT_CLEANUP