[ovs-dev,v8,2/3] Support LSP:options:requested-chassis as a list

diff --git a/NEWS b/NEWS
index f18a7d766..856d683f3 100644
--- a/NEWS
+++ b/NEWS
@@ -13,6 +13,7 @@  Post v22.03.0
     explicitly request routers to reply to any ARP/ND request for a VIP
     (when set to "all") and only for reachable VIPs (when set to "reachable"
     or by default).
+  - Support list of chassis for Logical_Switch_Port:options:requested-chassis.
 
 OVN v22.03.0 - 11 Mar 2022
 --------------------------
diff --git a/controller/binding.c b/controller/binding.c
index 6bdbe9912..066eec9a5 100644
--- a/controller/binding.c
+++ b/controller/binding.c
@@ -930,6 +930,130 @@  claimed_lport_set_up(const struct sbrec_port_binding *pb,
     }
 }
 
+typedef void (*set_func)(const struct sbrec_port_binding *pb,
+                         const struct sbrec_encap *);
+
+static bool
+update_port_encap_if_needed(const struct sbrec_port_binding *pb,
+                            const struct sbrec_chassis *chassis_rec,
+                            const struct ovsrec_interface *iface_rec,
+                            bool sb_readonly)
+{
+    const struct sbrec_encap *encap_rec =
+        sbrec_get_port_encap(chassis_rec, iface_rec);
+    if ((encap_rec && pb->encap != encap_rec) ||
+        (!encap_rec && pb->encap)) {
+        if (sb_readonly) {
+            return false;
+        }
+        sbrec_port_binding_set_encap(pb, encap_rec);
+    }
+    return true;
+}
+
+static void
+append_additional_encap(const struct sbrec_port_binding *pb,
+                        const struct sbrec_encap *encap)
+{
+    struct sbrec_encap **additional_encap = xmalloc(
+        (pb->n_additional_encap + 1) * (sizeof *additional_encap));
+    memcpy(additional_encap, pb->additional_encap,
+           pb->n_additional_encap * (sizeof *additional_encap));
+    additional_encap[pb->n_additional_encap] = (struct sbrec_encap *) encap;
+    sbrec_port_binding_set_additional_encap(
+        pb, additional_encap, pb->n_additional_encap + 1);
+    free(additional_encap);
+}
+
+static void
+remove_additional_encap_for_chassis(const struct sbrec_port_binding *pb,
+                                    const struct sbrec_chassis *chassis_rec)
+{
+    struct sbrec_encap **additional_encap = xmalloc(
+        pb->n_additional_encap * (sizeof *additional_encap));
+
+    int idx = 0;
+    for (int i = 0; i < pb->n_additional_encap; i++) {
+        if (!strcmp(pb->additional_encap[i]->chassis_name,
+                    chassis_rec->name)) {
+            continue;
+        }
+        additional_encap[idx++] = pb->additional_encap[i];
+    }
+    sbrec_port_binding_set_additional_encap(pb, additional_encap, idx);
+    free(additional_encap);
+}
+
+static bool
+update_port_additional_encap_if_needed(
+    const struct sbrec_port_binding *pb,
+    const struct sbrec_chassis *chassis_rec,
+    const struct ovsrec_interface *iface_rec,
+    bool sb_readonly)
+{
+    const struct sbrec_encap *encap_rec =
+        sbrec_get_port_encap(chassis_rec, iface_rec);
+    if (encap_rec) {
+        for (int i = 0; i < pb->n_additional_encap; i++) {
+            if (pb->additional_encap[i] == encap_rec) {
+                return true;
+            }
+        }
+        if (sb_readonly) {
+            return false;
+        }
+        append_additional_encap(pb, encap_rec);
+    }
+    return true;
+}
+
+static bool
+is_additional_chassis(const struct sbrec_port_binding *pb,
+                      const struct sbrec_chassis *chassis_rec)
+{
+    for (int i = 0; i < pb->n_additional_chassis; i++) {
+        if (pb->additional_chassis[i] == chassis_rec) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static void
+append_additional_chassis(const struct sbrec_port_binding *pb,
+                          const struct sbrec_chassis *chassis_rec)
+{
+    struct sbrec_chassis **additional_chassis = xmalloc(
+        (pb->n_additional_chassis + 1) * (sizeof *additional_chassis));
+    memcpy(additional_chassis, pb->additional_chassis,
+           pb->n_additional_chassis * (sizeof *additional_chassis));
+    additional_chassis[pb->n_additional_chassis] = (
+        (struct sbrec_chassis *) chassis_rec);
+    sbrec_port_binding_set_additional_chassis(
+        pb, additional_chassis, pb->n_additional_chassis + 1);
+    free(additional_chassis);
+}
+
+static void
+remove_additional_chassis(const struct sbrec_port_binding *pb,
+                          const struct sbrec_chassis *chassis_rec)
+{
+    struct sbrec_chassis **additional_chassis = xmalloc(
+        (pb->n_additional_chassis - 1) * (sizeof *additional_chassis));
+    int idx = 0;
+    for (int i = 0; i < pb->n_additional_chassis; i++) {
+        if (pb->additional_chassis[i] == chassis_rec) {
+            continue;
+        }
+        additional_chassis[idx++] = pb->additional_chassis[i];
+    }
+    sbrec_port_binding_set_additional_chassis(
+        pb, additional_chassis, pb->n_additional_chassis - 1);
+    free(additional_chassis);
+
+    remove_additional_encap_for_chassis(pb, chassis_rec);
+}
+
 /* Returns false if lport is not claimed due to 'sb_readonly'.
  * Returns true otherwise.
  */
@@ -946,40 +1070,65 @@  claim_lport(const struct sbrec_port_binding *pb,
         claimed_lport_set_up(pb, parent_pb, chassis_rec, notify_up, if_mgr);
     }
 
-    if (pb->chassis != chassis_rec) {
-        if (sb_readonly) {
-            return false;
-        }
+    enum can_bind can_bind = lport_can_bind_on_this_chassis(chassis_rec, pb);
+    bool update_tracked = false;
 
-        if (pb->chassis) {
-            VLOG_INFO("Changing chassis for lport %s from %s to %s.",
-                    pb->logical_port, pb->chassis->name,
-                    chassis_rec->name);
-        } else {
-            VLOG_INFO("Claiming lport %s for this chassis.", pb->logical_port);
-        }
-        for (int i = 0; i < pb->n_mac; i++) {
-            VLOG_INFO("%s: Claiming %s", pb->logical_port, pb->mac[i]);
+    if (can_bind == CAN_BIND_AS_MAIN) {
+        if (pb->chassis != chassis_rec) {
+            if (sb_readonly) {
+                return false;
+            }
+
+            if (pb->chassis) {
+                VLOG_INFO("Changing chassis for lport %s from %s to %s.",
+                        pb->logical_port, pb->chassis->name,
+                        chassis_rec->name);
+            } else {
+                VLOG_INFO("Claiming lport %s for this chassis.",
+                          pb->logical_port);
+            }
+            for (int i = 0; i < pb->n_mac; i++) {
+                VLOG_INFO("%s: Claiming %s", pb->logical_port, pb->mac[i]);
+            }
+
+            sbrec_port_binding_set_chassis(pb, chassis_rec);
+            if (is_additional_chassis(pb, chassis_rec)) {
+                remove_additional_chassis(pb, chassis_rec);
+            }
+            update_tracked = true;
         }
+    } else if (can_bind == CAN_BIND_AS_ADDITIONAL) {
+        if (!is_additional_chassis(pb, chassis_rec)) {
+            if (sb_readonly) {
+                return false;
+            }
 
-        sbrec_port_binding_set_chassis(pb, chassis_rec);
+            VLOG_INFO("Claiming lport %s for this additional chassis.",
+                      pb->logical_port);
+            for (int i = 0; i < pb->n_mac; i++) {
+                VLOG_INFO("%s: Claiming %s", pb->logical_port, pb->mac[i]);
+            }
 
-        if (tracked_datapaths) {
-            update_lport_tracking(pb, tracked_datapaths, true);
+            append_additional_chassis(pb, chassis_rec);
+            if (pb->chassis == chassis_rec) {
+                sbrec_port_binding_set_chassis(pb, NULL);
+            }
+            update_tracked = true;
         }
     }
 
-    /* Check if the port encap binding, if any, has changed */
-    struct sbrec_encap *encap_rec =
-        sbrec_get_port_encap(chassis_rec, iface_rec);
-    if ((encap_rec && pb->encap != encap_rec) ||
-        (!encap_rec && pb->encap)) {
-        if (sb_readonly) {
-            return false;
-        }
-        sbrec_port_binding_set_encap(pb, encap_rec);
+    if (update_tracked && tracked_datapaths) {
+        update_lport_tracking(pb, tracked_datapaths, true);
     }
 
+    /* Check if the port encap binding, if any, has changed */
+    if (can_bind == CAN_BIND_AS_MAIN) {
+        return update_port_encap_if_needed(
+            pb, chassis_rec, iface_rec, sb_readonly);
+    } else if (can_bind == CAN_BIND_AS_ADDITIONAL) {
+        return update_port_additional_encap_if_needed(
+            pb, chassis_rec, iface_rec, sb_readonly);
+    }
     return true;
 }
 
@@ -991,7 +1140,8 @@  claim_lport(const struct sbrec_port_binding *pb,
  * Caller should make sure that this is the case.
  */
 static bool
-release_lport_(const struct sbrec_port_binding *pb, bool sb_readonly)
+release_lport_main_chassis(const struct sbrec_port_binding *pb,
+                           bool sb_readonly)
 {
     if (pb->encap) {
         if (sb_readonly) {
@@ -1019,11 +1169,42 @@  release_lport_(const struct sbrec_port_binding *pb, bool sb_readonly)
 }
 
 static bool
-release_lport(const struct sbrec_port_binding *pb, bool sb_readonly,
+release_lport_additional_chassis(const struct sbrec_port_binding *pb,
+                                 const struct sbrec_chassis *chassis_rec,
+                                 bool sb_readonly)
+{
+    if (pb->additional_encap) {
+        if (sb_readonly) {
+            return false;
+        }
+        remove_additional_encap_for_chassis(pb, chassis_rec);
+    }
+
+    if (is_additional_chassis(pb, chassis_rec)) {
+        if (sb_readonly) {
+            return false;
+        }
+        remove_additional_chassis(pb, chassis_rec);
+    }
+
+    VLOG_INFO("Releasing lport %s from this additional chassis.",
+              pb->logical_port);
+    return true;
+}
+
+static bool
+release_lport(const struct sbrec_port_binding *pb,
+              const struct sbrec_chassis *chassis_rec, bool sb_readonly,
               struct hmap *tracked_datapaths, struct if_status_mgr *if_mgr)
 {
-    if (!release_lport_(pb, sb_readonly)) {
-        return false;
+    if (pb->chassis == chassis_rec) {
+        if (!release_lport_main_chassis(pb, sb_readonly)) {
+            return false;
+        }
+    } else if (is_additional_chassis(pb, chassis_rec)) {
+        if (!release_lport_additional_chassis(pb, chassis_rec, sb_readonly)) {
+            return false;
+        }
     }
 
     update_lport_tracking(pb, tracked_datapaths, false);
@@ -1042,7 +1223,8 @@  is_binding_lport_this_chassis(struct binding_lport *b_lport,
                               const struct sbrec_chassis *chassis)
 {
     return (b_lport && b_lport->pb && chassis &&
-            b_lport->pb->chassis == chassis);
+            (b_lport->pb->chassis == chassis
+             || is_additional_chassis(b_lport->pb, chassis)));
 }
 
 /* Returns 'true' if the 'lbinding' has binding lports of type LP_CONTAINER,
@@ -1067,7 +1249,7 @@  release_binding_lport(const struct sbrec_chassis *chassis_rec,
 {
     if (is_binding_lport_this_chassis(b_lport, chassis_rec)) {
         remove_related_lport(b_lport->pb, b_ctx_out);
-        if (!release_lport(b_lport->pb, sb_readonly,
+        if (!release_lport(b_lport->pb, chassis_rec, sb_readonly,
                            b_ctx_out->tracked_dp_bindings,
                            b_ctx_out->if_mgr)) {
             return false;
@@ -1116,22 +1298,21 @@  consider_vif_lport_(const struct sbrec_port_binding *pb,
         } else {
             /* We could, but can't claim the lport. */
             static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 1);
-                VLOG_INFO_RL(&rl,
-                             "Not claiming lport %s, chassis %s "
-                             "requested-chassis %s",
-                             pb->logical_port,
-                             b_ctx_in->chassis_rec->name,
-                             pb->requested_chassis ?
-                             pb->requested_chassis->name : "(option points at "
-                                                           "non-existent "
-                                                           "chassis)");
+            const char *requested_chassis_option = smap_get(
+                &pb->options, "requested-chassis");
+            VLOG_INFO_RL(&rl,
+                "Not claiming lport %s, chassis %s requested-chassis %s",
+                pb->logical_port, b_ctx_in->chassis_rec->name,
+                requested_chassis_option ? requested_chassis_option : "[]");
         }
     }
 
-    if (pb->chassis == b_ctx_in->chassis_rec) {
+    if (pb->chassis == b_ctx_in->chassis_rec
+            || is_additional_chassis(pb, b_ctx_in->chassis_rec)) {
         /* Release the lport if there is no lbinding. */
         if (!lbinding_set || !can_bind) {
-            return release_lport(pb, !b_ctx_in->ovnsb_idl_txn,
+            return release_lport(pb, b_ctx_in->chassis_rec,
+                                 !b_ctx_in->ovnsb_idl_txn,
                                  b_ctx_out->tracked_dp_bindings,
                                  b_ctx_out->if_mgr);
         }
@@ -1253,7 +1434,8 @@  consider_container_lport(const struct sbrec_port_binding *pb,
          * if it was bound earlier. */
         if (is_binding_lport_this_chassis(container_b_lport,
                                           b_ctx_in->chassis_rec)) {
-            return release_lport(pb, !b_ctx_in->ovnsb_idl_txn,
+            return release_lport(pb, b_ctx_in->chassis_rec,
+                                 !b_ctx_in->ovnsb_idl_txn,
                                  b_ctx_out->tracked_dp_bindings,
                                  b_ctx_out->if_mgr);
         }
@@ -1346,11 +1528,20 @@  consider_localport(const struct sbrec_port_binding *pb,
 
     /* If the port binding is claimed, then release it as localport is claimed
      * by any ovn-controller. */
-    if (pb->chassis == b_ctx_in->chassis_rec) {
-        if (!release_lport_(pb, !b_ctx_in->ovnsb_idl_txn)) {
+    enum can_bind can_bind = lport_can_bind_on_this_chassis(
+        b_ctx_in->chassis_rec, pb);
+    if (can_bind == CAN_BIND_AS_MAIN) {
+        if (!release_lport_main_chassis(pb, !b_ctx_in->ovnsb_idl_txn)) {
+            return false;
+        }
+    } else if (can_bind == CAN_BIND_AS_ADDITIONAL) {
+        if (!release_lport_additional_chassis(pb, b_ctx_in->chassis_rec,
+                                              !b_ctx_in->ovnsb_idl_txn)) {
             return false;
         }
+    }
 
+    if (can_bind) {
         remove_related_lport(pb, b_ctx_out);
     }
 
@@ -1381,8 +1572,12 @@  consider_nonvif_lport_(const struct sbrec_port_binding *pb,
                            !b_ctx_in->ovnsb_idl_txn, false,
                            b_ctx_out->tracked_dp_bindings,
                            b_ctx_out->if_mgr);
-    } else if (pb->chassis == b_ctx_in->chassis_rec) {
-        return release_lport(pb, !b_ctx_in->ovnsb_idl_txn,
+    }
+
+    if (pb->chassis == b_ctx_in->chassis_rec ||
+            is_additional_chassis(pb, b_ctx_in->chassis_rec)) {
+        return release_lport(pb, b_ctx_in->chassis_rec,
+                             !b_ctx_in->ovnsb_idl_txn,
                              b_ctx_out->tracked_dp_bindings,
                              b_ctx_out->if_mgr);
     }
@@ -1709,6 +1904,11 @@  binding_cleanup(struct ovsdb_idl_txn *ovnsb_idl_txn,
             sbrec_port_binding_set_chassis(binding_rec, NULL);
             any_changes = true;
         }
+        if (is_additional_chassis(binding_rec, chassis_rec)) {
+            remove_additional_encap_for_chassis(binding_rec, chassis_rec);
+            remove_additional_chassis(binding_rec, chassis_rec);
+            any_changes = true;
+        }
     }
 
     if (any_changes) {
diff --git a/controller/lport.c b/controller/lport.c
index 5ad40f6d3..d88215715 100644
--- a/controller/lport.c
+++ b/controller/lport.c
@@ -108,29 +108,41 @@  lport_get_l3gw_peer(const struct sbrec_port_binding *pb,
     return get_peer_lport(pb, sbrec_port_binding_by_name);
 }
 
-bool
+enum can_bind
 lport_can_bind_on_this_chassis(const struct sbrec_chassis *chassis_rec,
                                const struct sbrec_port_binding *pb)
 {
-    /* We need to check for presence of the requested-chassis option in
-     * addittion to checking the pb->requested_chassis column because this
-     * column will be set to NULL whenever the option points to a non-existent
-     * chassis.  As the controller routinely clears its own chassis record this
-     * might occur more often than one might think. */
+    if (pb->requested_chassis == chassis_rec) {
+        return CAN_BIND_AS_MAIN;
+    }
+
+    for (int i = 0; i < pb->n_requested_additional_chassis; i++) {
+        if (pb->requested_additional_chassis[i] == chassis_rec) {
+            return CAN_BIND_AS_ADDITIONAL;
+        }
+    }
+
     const char *requested_chassis_option = smap_get(&pb->options,
                                                     "requested-chassis");
-    if (requested_chassis_option && requested_chassis_option[0]
-        && !pb->requested_chassis) {
-        /* The requested-chassis option is set, but the requested_chassis
-         * column is not filled.  This means that the chassis the option
-         * points to is currently not running, or is in the process of starting
-         * up.  In this case we must fall back to comparing the strings to
-         * avoid release/claim thrashing. */
-        return !strcmp(requested_chassis_option, chassis_rec->name)
-               || !strcmp(requested_chassis_option, chassis_rec->hostname);
+    if (!requested_chassis_option || !strcmp("", requested_chassis_option)) {
+        return CAN_BIND_AS_MAIN;
+    }
+
+    char *tokstr = xstrdup(requested_chassis_option);
+    char *save_ptr = NULL;
+    char *chassis;
+    enum can_bind can_bind = CAN_BIND_AS_MAIN;
+    for (chassis = strtok_r(tokstr, ",", &save_ptr); chassis != NULL;
+         chassis = strtok_r(NULL, ",", &save_ptr)) {
+        if (!strcmp(chassis, chassis_rec->name)
+                || !strcmp(chassis, chassis_rec->hostname)) {
+            free(tokstr);
+            return can_bind;
+        }
+        can_bind = CAN_BIND_AS_ADDITIONAL;
     }
-    return !requested_chassis_option || !requested_chassis_option[0]
-           || chassis_rec == pb->requested_chassis;
+    free(tokstr);
+    return CANNOT_BIND;
 }
 
 const struct sbrec_datapath_binding *
diff --git a/controller/lport.h b/controller/lport.h
index 4716c58f9..115881655 100644
--- a/controller/lport.h
+++ b/controller/lport.h
@@ -43,8 +43,15 @@  const struct sbrec_port_binding *lport_lookup_by_key(
     struct ovsdb_idl_index *sbrec_port_binding_by_key,
     uint64_t dp_key, uint64_t port_key);
 
-bool lport_can_bind_on_this_chassis(const struct sbrec_chassis *chassis_rec,
-                                   const struct sbrec_port_binding *pb);
+enum can_bind {
+    CANNOT_BIND = 0,
+    CAN_BIND_AS_MAIN,
+    CAN_BIND_AS_ADDITIONAL,
+};
+
+enum can_bind
+lport_can_bind_on_this_chassis(const struct sbrec_chassis *chassis_rec,
+                               const struct sbrec_port_binding *pb);
 
 const struct sbrec_datapath_binding *datapath_lookup_by_key(
     struct ovsdb_idl_index *sbrec_datapath_binding_by_key, uint64_t dp_key);
diff --git a/northd/northd.c b/northd/northd.c
index 6138d42ad..3e4c90957 100644
--- a/northd/northd.c
+++ b/northd/northd.c
@@ -3244,31 +3244,53 @@  ovn_port_update_sbrec_chassis(
         const struct ovn_port *op)
 {
     const char *requested_chassis; /* May be NULL. */
-    bool reset_requested_chassis = false;
+
+    int n_requested_chassis = 0;
+    struct sbrec_chassis **requested_chassis_sb = xcalloc(
+        n_requested_chassis, sizeof *requested_chassis_sb);
+
     requested_chassis = smap_get(&op->nbsp->options,
                                  "requested-chassis");
     if (requested_chassis) {
-        const struct sbrec_chassis *chassis = chassis_lookup(
-            sbrec_chassis_by_name, sbrec_chassis_by_hostname,
-            requested_chassis);
-        if (chassis) {
-            sbrec_port_binding_set_requested_chassis(op->sb, chassis);
-        } else {
-            reset_requested_chassis = true;
-            static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(
-                1, 1);
-            VLOG_WARN_RL(
-                &rl,
-                "Unknown chassis '%s' set as "
-                "options:requested-chassis on LSP '%s'.",
-                requested_chassis, op->nbsp->name);
-        }
-    } else if (op->sb->requested_chassis) {
-        reset_requested_chassis = true;
-    }
-    if (reset_requested_chassis) {
+        char *tokstr = xstrdup(requested_chassis);
+        char *save_ptr = NULL;
+        char *chassis;
+        for (chassis = strtok_r(tokstr, ",", &save_ptr); chassis != NULL;
+             chassis = strtok_r(NULL, ",", &save_ptr)) {
+            const struct sbrec_chassis *chassis_sb = chassis_lookup(
+                sbrec_chassis_by_name, sbrec_chassis_by_hostname, chassis);
+            if (chassis_sb) {
+                requested_chassis_sb = xrealloc(
+                    requested_chassis_sb,
+                    ++n_requested_chassis * (sizeof *requested_chassis_sb));
+                requested_chassis_sb[n_requested_chassis - 1] = (
+                    (struct sbrec_chassis *) chassis_sb);
+            } else {
+                static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(
+                    1, 1);
+                VLOG_WARN_RL(
+                    &rl,
+                    "Unknown chassis '%s' set in "
+                    "options:requested-chassis on LSP '%s'.",
+                    chassis, op->nbsp->name);
+            }
+        }
+        free(tokstr);
+    }
+
+    if (n_requested_chassis > 0) {
+        sbrec_port_binding_set_requested_chassis(op->sb,
+                                                 *requested_chassis_sb);
+    } else {
         sbrec_port_binding_set_requested_chassis(op->sb, NULL);
     }
+    if (n_requested_chassis > 1) {
+        sbrec_port_binding_set_requested_additional_chassis(
+            op->sb, &requested_chassis_sb[1], n_requested_chassis - 1);
+    } else {
+        sbrec_port_binding_set_requested_additional_chassis(op->sb, NULL, 0);
+    }
+    free(requested_chassis_sb);
 }
 
 static void
diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
index 0a0f85010..1cfc2024d 100644
--- a/northd/ovn-northd.c
+++ b/northd/ovn-northd.c
@@ -100,7 +100,9 @@  static const char *rbac_fdb_update[] =
 static const char *rbac_port_binding_auth[] =
     {""};
 static const char *rbac_port_binding_update[] =
-    {"chassis", "encap", "up", "virtual_parent"};
+    {"chassis", "additional_chassis",
+     "encap", "additional_encap",
+     "up", "virtual_parent"};
 
 static const char *rbac_mac_binding_auth[] =
     {""};
diff --git a/ovn-nb.xml b/ovn-nb.xml
index 225e0cf9c..5e521df60 100644
--- a/ovn-nb.xml
+++ b/ovn-nb.xml
@@ -1020,12 +1020,20 @@ 
         </p>
 
         <column name="options" key="requested-chassis">
-          If set, identifies a specific chassis (by name or hostname) 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.
+          <p>
+            If set, identifies a specific chassis (by name or hostname) 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.
+          </p>
+
+          <p>
+            If set to a comma separated list, the first entry identifies the
+            main chassis and the rest are one or more additional chassis that
+            are allowed to bind the same port.
+          </p>
         </column>
 
         <column name="options" key="iface-id-ver">
diff --git a/ovn-sb.ovsschema b/ovn-sb.ovsschema
index 66664c840..fcd74b918 100644
--- a/ovn-sb.ovsschema
+++ b/ovn-sb.ovsschema
@@ -1,7 +1,7 @@ 
 {
     "name": "OVN_Southbound",
     "version": "20.22.0",
-    "cksum": "1686121686 27471",
+    "cksum": "2805878321 28417",
     "tables": {
         "SB_Global": {
             "columns": {
@@ -218,10 +218,18 @@ 
                                              "refTable": "Chassis",
                                              "refType": "weak"},
                                      "min": 0, "max": 1}},
+                "additional_chassis": {"type": {"key": {"type": "uuid",
+                                                        "refTable": "Chassis",
+                                                        "refType": "weak"},
+                                               "min": 0, "max": "unlimited"}},
                 "encap": {"type": {"key": {"type": "uuid",
                                             "refTable": "Encap",
                                              "refType": "weak"},
                                     "min": 0, "max": 1}},
+                "additional_encap": {"type": {"key": {"type": "uuid",
+                                                      "refTable": "Encap",
+                                                      "refType": "weak"},
+                                    "min": 0, "max": "unlimited"}},
                 "mac": {"type": {"key": "string",
                                  "min": 0,
                                  "max": "unlimited"}},
@@ -236,7 +244,12 @@ 
                 "requested_chassis": {"type": {"key": {"type": "uuid",
                                                        "refTable": "Chassis",
                                                        "refType": "weak"},
-                                               "min": 0, "max": 1}}},
+                                               "min": 0, "max": 1}},
+                "requested_additional_chassis": {
+                                      "type": {"key": {"type": "uuid",
+                                                       "refTable": "Chassis",
+                                                       "refType": "weak"},
+                                               "min": 0, "max": "unlimited"}}},
             "indexes": [["datapath", "tunnel_key"], ["logical_port"]],
             "isRoot": true},
         "MAC_Binding": {
diff --git a/ovn-sb.xml b/ovn-sb.xml
index b0b11b8ee..0393d1220 100644
--- a/ovn-sb.xml
+++ b/ovn-sb.xml
@@ -2867,9 +2867,17 @@  tcp.flags = RST;
       </column>
 
       <column name="encap">
-        Points to supported encapsulation configurations to transmit
-        logical dataplane packets to this chassis.  Each entry is a <ref
-        table="Encap"/> record that describes the configuration.
+        Points to preferred encapsulation configuration to transmit
+        logical dataplane packets to this chassis. The entry is reference to
+        a <ref table="Encap"/> record.
+      </column>
+
+      <column name="additional_encap">
+        Points to preferred encapsulation configuration to transmit
+        logical dataplane packets to this additional chassis. The entry is
+        reference to a <ref table="Encap"/> record.
+
+        See also <ref column="additional_chassis"/>.
       </column>
 
       <column name="chassis">
@@ -2921,6 +2929,13 @@  tcp.flags = RST;
 
       </column>
 
+      <column name="additional_chassis">
+        The meaning of this column is the same as for the
+        <ref column="chassis"/>. The column is used to track an additional
+        physical location of the logical port. Used with regular (empty
+        <ref column="type"/>) port bindings.
+      </column>
+
       <column name="gateway_chassis">
         <p>
           A list of <ref table="Gateway_Chassis"/>.
@@ -3079,6 +3094,28 @@  tcp.flags = RST;
         db="OVN_Northbound"/>
         is defined and contains a string matching the name or hostname of an
         existing chassis.
+
+        See also
+        <ref table="Port_Binding" column="requested_additional_chassis"/>.
+      </column>
+      <column name="requested_additional_chassis">
+        This column exists so that the ovn-controller can effectively monitor
+        all <ref table="Port_Binding"/> records destined for it, and is a
+        supplement to the <ref
+        table="Port_Binding"
+        column="options"
+        key="requested-chassis"/> option when multiple chassis are listed.
+
+        This column must be a list of
+        <ref table="Chassis"/> records.  This is populated by
+        <code>ovn-northd</code> when the <ref
+        table="Logical_Switch_Port"
+        column="options"
+        key="requested-chassis"
+        db="OVN_Northbound"/>
+        is defined as a list of chassis names or hostnames.
+
+        See also <ref table="Port_Binding" column="requested_chassis"/>.
       </column>
     </group>
 
@@ -3238,12 +3275,20 @@  tcp.flags = RST;
       </p>
 
       <column name="options" key="requested-chassis">
-        If set, identifies a specific chassis (by name or hostname) 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.
+        <p>
+          If set, identifies a specific chassis (by name or hostname) 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.
+        </p>
+
+        <p>
+          If set to a comma separated list, the first entry identifies the main
+          chassis and the rest are one or more additional chassis that are
+          allowed to bind the same port.
+        </p>
       </column>
 
       <column name="options" key="iface-id-ver">
diff --git a/tests/ovn.at b/tests/ovn.at
index bb00d8e1a..a703effff 100644
--- a/tests/ovn.at
+++ b/tests/ovn.at
@@ -13968,6 +13968,224 @@  OVN_CLEANUP([hv1])
 AT_CLEANUP
 ])
 
+OVN_FOR_EACH_NORTHD([
+AT_SETUP([options:multiple requested-chassis for logical port])
+ovn_start
+
+net_add n1
+
+sim_add hv1
+as hv1
+check ovs-vsctl add-br br-phys
+ovn_attach n1 br-phys 192.168.0.11
+
+sim_add hv2
+as hv2
+check ovs-vsctl add-br br-phys
+ovn_attach n1 br-phys 192.168.0.12
+
+check ovn-nbctl ls-add ls0
+check ovn-nbctl lsp-add ls0 lsp0
+
+# Allow only chassis hv1 to bind logical port lsp0.
+check ovn-nbctl lsp-set-options lsp0 requested-chassis=hv1
+
+as hv1 check ovs-vsctl -- add-port br-int lsp0 -- \
+    set Interface lsp0 external-ids:iface-id=lsp0
+as hv2 check ovs-vsctl -- add-port br-int lsp0 -- \
+    set Interface lsp0 external-ids:iface-id=lsp0
+
+wait_row_count Chassis 1 name=hv1
+wait_row_count Chassis 1 name=hv2
+hv1_uuid=$(fetch_column Chassis _uuid name=hv1)
+hv2_uuid=$(fetch_column Chassis _uuid name=hv2)
+
+wait_column "$hv1_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "" Port_Binding additional_chassis logical_port=lsp0
+wait_column "" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Request port binding at an additional chassis
+check ovn-nbctl lsp-set-options lsp0 \
+    requested-chassis=hv1,hv2
+
+wait_column "$hv1_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv2_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Check that setting iface:encap-ip populates Port_Binding:additional_encap
+wait_row_count Encap 2 chassis_name=hv1
+wait_row_count Encap 2 chassis_name=hv2
+encap_hv1_uuid=$(fetch_column Encap _uuid chassis_name=hv1 type=geneve)
+encap_hv2_uuid=$(fetch_column Encap _uuid chassis_name=hv2 type=geneve)
+
+wait_column "" Port_Binding encap logical_port=lsp0
+wait_column "" Port_Binding additional_encap logical_port=lsp0
+
+as hv1 check ovs-vsctl -- \
+    set Interface lsp0 external-ids:encap-ip=192.168.0.11
+as hv2 check ovs-vsctl -- \
+    set Interface lsp0 external-ids:encap-ip=192.168.0.12
+
+wait_column "$encap_hv1_uuid" Port_Binding encap logical_port=lsp0
+wait_column "$encap_hv2_uuid" Port_Binding additional_encap logical_port=lsp0
+
+# Complete moving the binding to the new location
+check ovn-nbctl lsp-set-options lsp0 requested-chassis=hv2
+
+wait_column "$hv2_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv2_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "" Port_Binding additional_chassis logical_port=lsp0
+wait_column "" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Check that additional_encap is cleared
+wait_column "" Port_Binding additional_encap logical_port=lsp0
+
+# Check that abrupted port migration clears additional_encap
+check ovn-nbctl lsp-set-options lsp0 \
+    requested-chassis=hv2,hv1
+wait_column "$hv2_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv2_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+check ovn-nbctl lsp-set-options lsp0 requested-chassis=hv2
+wait_column "" Port_Binding additional_encap logical_port=lsp0
+
+OVN_CLEANUP([hv1],[hv2])
+
+AT_CLEANUP
+])
+
+OVN_FOR_EACH_NORTHD([
+AT_SETUP([options:multiple requested-chassis for logical port: change chassis role])
+ovn_start
+
+net_add n1
+
+for i in 1 2 3; do
+    sim_add hv$i
+    as hv$i
+    check ovs-vsctl add-br br-phys
+    ovn_attach n1 br-phys 192.168.0.1$i
+done
+
+check ovn-nbctl ls-add ls0
+check ovn-nbctl lsp-add ls0 lsp0
+
+# Bind the port to all of them
+check ovn-nbctl lsp-set-options lsp0 requested-chassis=hv1,hv2,hv3
+
+for i in 1 2 3; do
+    as hv$i check ovs-vsctl -- add-port br-int lsp0 -- \
+        set Interface lsp0 external-ids:iface-id=lsp0
+done
+
+for i in 1 2 3; do
+    wait_row_count Chassis 1 name=hv$i
+done
+hv1_uuid=$(fetch_column Chassis _uuid name=hv1)
+hv2_uuid=$(fetch_column Chassis _uuid name=hv2)
+hv3_uuid=$(fetch_column Chassis _uuid name=hv3)
+
+wait_column "$hv1_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Now swap hv1 and hv2 chassis roles: main <-> additional
+check ovn-nbctl lsp-set-options lsp0 requested-chassis=hv3,hv2,hv1
+
+wait_column "$hv3_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv3_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv1_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv1_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+OVN_CLEANUP([hv1],[hv2],[hv3])
+
+AT_CLEANUP
+])
+
+OVN_FOR_EACH_NORTHD([
+AT_SETUP([options:multiple requested-chassis for logical port: unclaimed behavior])
+ovn_start
+
+net_add n1
+
+for i in 1 2 3; do
+    sim_add hv$i
+    as hv$i
+    check ovs-vsctl add-br br-phys
+    ovn_attach n1 br-phys 192.168.0.1$i
+done
+
+check ovn-nbctl ls-add ls0
+check ovn-nbctl lsp-add ls0 lsp0
+
+# Bind the port to all of them
+check ovn-nbctl lsp-set-options lsp0 requested-chassis=hv1,hv2,hv3
+
+for i in 1 2 3; do
+    wait_row_count Chassis 1 name=hv$i
+done
+hv1_uuid=$(fetch_column Chassis _uuid name=hv1)
+hv2_uuid=$(fetch_column Chassis _uuid name=hv2)
+hv3_uuid=$(fetch_column Chassis _uuid name=hv3)
+
+# Port not claimed by any of chassis
+wait_column "" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Now claim on main chassis
+as hv1 check ovs-vsctl -- add-port br-int lsp0 -- \
+    set Interface lsp0 external-ids:iface-id=lsp0
+
+wait_column "$hv1_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Now claim on the second additional chassis
+as hv3 check ovs-vsctl -- add-port br-int lsp0 -- \
+    set Interface lsp0 external-ids:iface-id=lsp0
+
+wait_column "$hv1_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv3_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Now claim the other additional chassis
+as hv2 check ovs-vsctl -- add-port br-int lsp0 -- \
+    set Interface lsp0 external-ids:iface-id=lsp0
+
+wait_column "$hv1_uuid" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Now unclaim from the main chassis
+as hv1 check ovs-vsctl -- del-port br-int lsp0
+
+wait_column "" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+# Now unclaim from an additional chassis
+as hv3 check ovs-vsctl -- del-port br-int lsp0
+
+wait_column "" Port_Binding chassis logical_port=lsp0
+wait_column "$hv1_uuid" Port_Binding requested_chassis logical_port=lsp0
+wait_column "$hv2_uuid" Port_Binding additional_chassis logical_port=lsp0
+wait_column "$hv2_uuid $hv3_uuid" Port_Binding requested_additional_chassis logical_port=lsp0
+
+OVN_CLEANUP([hv1],[hv2],[hv3])
+
+AT_CLEANUP
+])
+
 OVN_FOR_EACH_NORTHD([
 AT_SETUP([options:requested-chassis for logical port])
 ovn_start