1) Added a new option "distributed" for load balancers.
   With this feature, balancers will work distributedly across compute nodes,
   balancing to only local backends.

2) If the balancer is running on a router with dgp, the router will no longer 
be centralized.

3) For such balancers, it is necessary to specify ip_port_mapping for the 
correct formation of logical flows.

4) Balancing occurs through a new action 'ct_lb_mark_local'.

Example:
Load Balancer: lb1 with VIP 10.255.0.1 and distributed option enabled.
Fabric is configured with a static ECMP route for 10.255.0.1/32:
    nexthop via ip_host1 weight 1 (hosts backend1)
    nexthop via ip_host2 weight 1 (hosts backend2)
    nexthop via ip_host3 weight 2 (hosts backend3 and backend4)

As part of testing, following estimates of distribution of requests to 
balancers were obtained:
[root@dev11 ~]# for i in $(seq 5000); do curl http://10.255.0.1:80 2>/dev/null 
; echo ; done | awk '{print $2}' | sort | uniq -c
   1265 “backend 4",
   1260 “backend 3",
   1224 “backend 2",
   1251 “backend 1",
Thus, requests using ecmp balancing are distributed between backends 
approximately evenly.

Suggested-by: Vladislav Odintsov <[email protected]>
Signed-off-by: Alexandra Rukomoinikova <[email protected]>
---
v2 --> v3: fixed Lorenzo comments, added NEWS
---
 NEWS                    |   3 +
 northd/en-lb-data.c     |   8 +
 northd/en-lb-data.h     |   3 +
 northd/en-lr-stateful.c |   4 +
 northd/en-lr-stateful.h |   2 +
 northd/lb.c             |  93 ++++++-----
 northd/lb.h             |   4 +
 northd/northd.c         | 169 ++++++++++++++-----
 northd/northd.h         |   5 +
 ovn-nb.xml              |  15 +-
 tests/ovn-northd.at     | 355 ++++++++++++++++++++++++++++++++++++++++
 tests/system-ovn.at     | 245 +++++++++++++++++++++++++++
 12 files changed, 821 insertions(+), 85 deletions(-)

diff --git a/NEWS b/NEWS
index a4c8557ee..95193ce65 100644
--- a/NEWS
+++ b/NEWS
@@ -69,6 +69,9 @@ Post v25.09.0
   - Add a new experimental service - ovn-br-controller to program and
     manage OVS bridges (not managed by ovn-controller) using OVN logical flows.
     For more details see man ovn-br(5).
+  - Add "distributed" option for load balancer, that forces traffic to be
+    routed only to backend instances running locally on the same chassis
+    it arrives on.
 
 OVN v25.09.0 - xxx xx xxxx
 --------------------------
diff --git a/northd/en-lb-data.c b/northd/en-lb-data.c
index 6d52d465e..6547a961f 100644
--- a/northd/en-lb-data.c
+++ b/northd/en-lb-data.c
@@ -166,6 +166,7 @@ lb_data_load_balancer_handler(struct engine_node *node, 
void *data)
             add_crupdated_lb_to_tracked_data(lb, trk_lb_data,
                                              lb->health_checks);
             trk_lb_data->has_routable_lb |= lb->routable;
+            trk_lb_data->has_distributed_lb |= lb->is_distributed;
             continue;
         }
 
@@ -180,6 +181,7 @@ lb_data_load_balancer_handler(struct engine_node *node, 
void *data)
             add_deleted_lb_to_tracked_data(lb, trk_lb_data,
                                            lb->health_checks);
             trk_lb_data->has_routable_lb |= lb->routable;
+            trk_lb_data->has_distributed_lb |= lb->is_distributed;
         } else {
             /* Load balancer updated. */
             bool health_checks = lb->health_checks;
@@ -189,11 +191,13 @@ lb_data_load_balancer_handler(struct engine_node *node, 
void *data)
             sset_swap(&lb->ips_v6, &old_ips_v6);
             enum lb_neighbor_responder_mode neigh_mode = lb->neigh_mode;
             bool routable = lb->routable;
+            bool distributed_mode = lb->is_distributed;
             ovn_northd_lb_reinit(lb, tracked_lb);
             health_checks |= lb->health_checks;
             struct crupdated_lb *clb = add_crupdated_lb_to_tracked_data(
                 lb, trk_lb_data, health_checks);
             trk_lb_data->has_routable_lb |= lb->routable;
+            trk_lb_data->has_distributed_lb |= lb->is_distributed;
 
             /* Determine the inserted and deleted vips and store them in
              * the tracked data. */
@@ -226,6 +230,10 @@ lb_data_load_balancer_handler(struct engine_node *node, 
void *data)
                 /* If neigh_mode is updated trigger a full recompute. */
                 return EN_UNHANDLED;
             }
+            if (distributed_mode != lb->is_distributed) {
+                /* If neigh_mode is updated trigger a full recompute. */
+                return EN_UNHANDLED;
+            }
         }
     }
 
diff --git a/northd/en-lb-data.h b/northd/en-lb-data.h
index 1da087656..90e85b8c4 100644
--- a/northd/en-lb-data.h
+++ b/northd/en-lb-data.h
@@ -82,6 +82,9 @@ struct tracked_lb_data {
 
     /* Indicates if any lb (in the tracked data) has 'routable' flag set. */
     bool has_routable_lb;
+
+    /* Indicates if any lb (in the tracked data) has 'distibuted' flag set. */
+    bool has_distributed_lb;
 };
 
 /* Datapath (logical switch) to lb/lbgrp association data. */
diff --git a/northd/en-lr-stateful.c b/northd/en-lr-stateful.c
index 5eec1e11a..55788c06c 100644
--- a/northd/en-lr-stateful.c
+++ b/northd/en-lr-stateful.c
@@ -325,7 +325,9 @@ lr_stateful_lb_data_handler(struct engine_node *node, void 
*data_)
             const struct ovn_datapath *od =
                 ovn_datapaths_find_by_index(input_data.lr_datapaths,
                                             lr_stateful_rec->lr_index);
+
             lr_stateful_rec->has_lb_vip = od_has_lb_vip(od);
+            lr_stateful_rec->has_distributed_lb = od->is_distributed;
         }
 
         return EN_HANDLED_UPDATED;
@@ -527,7 +529,9 @@ lr_stateful_record_create(struct lr_stateful_table *table,
     if (nbr->n_nat) {
         lr_stateful_rebuild_vip_nats(lr_stateful_rec);
     }
+
     lr_stateful_rec->has_lb_vip = od_has_lb_vip(od);
+    lr_stateful_rec->has_distributed_lb = od->is_distributed;
 
     hmap_insert(&table->entries, &lr_stateful_rec->key_node,
                 uuid_hash(&lr_stateful_rec->nbr_uuid));
diff --git a/northd/en-lr-stateful.h b/northd/en-lr-stateful.h
index 146f768c3..3b0c54521 100644
--- a/northd/en-lr-stateful.h
+++ b/northd/en-lr-stateful.h
@@ -59,6 +59,8 @@ struct lr_stateful_record {
 
     bool has_lb_vip;
 
+    bool has_distributed_lb;
+
     /* Load Balancer vIPs relevant for this datapath. */
     struct ovn_lb_ip_set *lb_ips;
 
diff --git a/northd/lb.c b/northd/lb.c
index 919557ec4..b5bf18689 100644
--- a/northd/lb.c
+++ b/northd/lb.c
@@ -85,12 +85,12 @@ ovn_lb_ip_set_clone(struct ovn_lb_ip_set *lb_ip_set)
     return clone;
 }
 
-static
-void ovn_northd_lb_vip_init(struct ovn_northd_lb_vip *lb_vip_nb,
-                            const struct ovn_lb_vip *lb_vip,
-                            const struct nbrec_load_balancer *nbrec_lb,
-                            const char *vip_port_str, const char *backend_ips,
-                            bool template)
+static void
+ovn_northd_lb_vip_init(struct ovn_northd_lb_vip *lb_vip_nb,
+                       const struct ovn_lb_vip *lb_vip,
+                       const struct nbrec_load_balancer *nbrec_lb,
+                       const char *vip_port_str, const char *backend_ips,
+                       bool template)
 {
     lb_vip_nb->backend_ips = xstrdup(backend_ips);
     lb_vip_nb->n_backends = vector_len(&lb_vip->backends);
@@ -101,19 +101,24 @@ void ovn_northd_lb_vip_init(struct ovn_northd_lb_vip 
*lb_vip_nb,
 }
 
 /*
- * Initializes health check configuration for load balancer VIP
- * backends. Parses the ip_port_mappings in the format :
- * "ip:logical_port:src_ip[:az_name]".
+ * Parses ip_port_mappings in the format :
+ * "ip:logical_port[:src_ip][:az_name]".
+ * src_ip parameter is optional when distributed mode is enabled,
+ * without health checks configured.
  * If az_name is present and non-empty, it indicates this is a
  * remote service monitor (backend is in another availability zone),
  * it should be propogated to another AZ by interconnection processing.
+ * This configuration required for health check and distributed working
+ * of load_balancer.
  */
 static void
-ovn_lb_vip_backends_health_check_init(const struct ovn_northd_lb *lb,
-                                      const struct ovn_lb_vip *lb_vip,
-                                      struct ovn_northd_lb_vip *lb_vip_nb)
+ovn_lb_vip_backends_ip_port_mappings_init(const struct ovn_northd_lb *lb,
+                                          const struct ovn_lb_vip *lb_vip,
+                                          struct ovn_northd_lb_vip *lb_vip_nb)
 {
     struct ds key = DS_EMPTY_INITIALIZER;
+    bool allow_without_src_ip = lb->is_distributed
+                                && !lb_vip_nb->lb_health_check;
 
     for (size_t j = 0; j < vector_len(&lb_vip->backends); j++) {
         const struct ovn_lb_backend *backend =
@@ -127,26 +132,34 @@ ovn_lb_vip_backends_health_check_init(const struct 
ovn_northd_lb *lb,
             continue;
         }
 
-        char *svc_mon_src_ip = NULL;
-        char *az_name = NULL;
+        struct ovn_northd_lb_backend *backend_nb = NULL;
+        char *port_name = NULL, *az_name = NULL, *first_colon = NULL;
+        char *svc_mon_src_ip = NULL, *src_ip = NULL;
         bool is_remote = false;
-        char *port_name = xstrdup(s);
-        char *src_ip = NULL;
 
-        char *first_colon = strchr(port_name, ':');
-        if (!first_colon) {
-            free(port_name);
-            continue;
+        port_name = xstrdup(s);
+        first_colon = strchr(port_name, ':');
+
+        if (!first_colon && allow_without_src_ip) {
+            if (!*port_name) {
+                VLOG_WARN("Empty port name in distributed mode for IP %s",
+                          ds_cstr(&key));
+                goto cleanup;
+            }
+            is_remote = false;
+            goto init_backend;
+        } else if (!first_colon) {
+            VLOG_WARN("Expected ':' separator for: %s", port_name);
+            goto cleanup;
         }
-        *first_colon = '\0';
 
+        *first_colon = '\0';
         if (first_colon[1] == '[') {
             /* IPv6 case - format: port:[ipv6]:az or port:[ipv6] */
             char *ip_end = strchr(first_colon + 2, ']');
             if (!ip_end) {
                 VLOG_WARN("Malformed IPv6 address in backend %s", s);
-                free(port_name);
-                continue;
+                goto cleanup;
             }
 
             src_ip = first_colon + 2;
@@ -157,8 +170,7 @@ ovn_lb_vip_backends_health_check_init(const struct 
ovn_northd_lb *lb,
                 if (!*az_name) {
                     VLOG_WARN("Empty AZ name specified for backend %s",
                               port_name);
-                    free(port_name);
-                    continue;
+                    goto cleanup;
                 }
                 is_remote = true;
             }
@@ -172,31 +184,31 @@ ovn_lb_vip_backends_health_check_init(const struct 
ovn_northd_lb *lb,
                 if (!*az_name) {
                     VLOG_WARN("Empty AZ name specified for backend %s",
                               port_name);
-                    free(port_name);
-                    continue;
+                    goto cleanup;
                 }
-            is_remote = true;
+                is_remote = true;
             }
         }
 
         struct sockaddr_storage svc_mon_src_addr;
         if (!src_ip || !inet_parse_address(src_ip, &svc_mon_src_addr)) {
             VLOG_WARN("Invalid svc mon src IP %s", src_ip ? src_ip : "NULL");
+            goto cleanup;
         } else {
             struct ds src_ip_s = DS_EMPTY_INITIALIZER;
             ss_format_address_nobracks(&svc_mon_src_addr, &src_ip_s);
             svc_mon_src_ip = ds_steal_cstr(&src_ip_s);
         }
 
-        if (svc_mon_src_ip) {
-            struct ovn_northd_lb_backend *backend_nb =
-                &lb_vip_nb->backends_nb[j];
-            backend_nb->health_check = true;
-            backend_nb->logical_port = xstrdup(port_name);
-            backend_nb->svc_mon_src_ip = svc_mon_src_ip;
-            backend_nb->az_name = is_remote ? xstrdup(az_name) : NULL;
-            backend_nb->remote_backend = is_remote;
-        }
+init_backend:
+        backend_nb = &lb_vip_nb->backends_nb[j];
+        backend_nb->health_check = lb_vip_nb->lb_health_check;
+        backend_nb->logical_port = xstrdup(port_name);
+        backend_nb->svc_mon_src_ip = svc_mon_src_ip;
+        backend_nb->az_name = is_remote ? xstrdup(az_name) : NULL;
+        backend_nb->remote_backend = is_remote;
+        backend_nb->distributed_backend = lb->is_distributed;
+cleanup:
         free(port_name);
     }
 
@@ -364,6 +376,9 @@ ovn_northd_lb_init(struct ovn_northd_lb *lb,
         lb->hairpin_snat_ip = xstrdup(snat_ip);
     }
 
+    lb->is_distributed = smap_get_bool(&nbrec_lb->options, "distributed",
+                                       false);
+
     sset_init(&lb->ips_v4);
     sset_init(&lb->ips_v6);
     struct smap_node *node;
@@ -403,8 +418,8 @@ ovn_northd_lb_init(struct ovn_northd_lb *lb,
         }
         n_vips++;
 
-        if (lb_vip_nb->lb_health_check) {
-            ovn_lb_vip_backends_health_check_init(lb, lb_vip, lb_vip_nb);
+        if (lb_vip_nb->lb_health_check || lb->is_distributed) {
+            ovn_lb_vip_backends_ip_port_mappings_init(lb, lb_vip, lb_vip_nb);
         }
     }
 
diff --git a/northd/lb.h b/northd/lb.h
index 43a8a1850..bd7fe641c 100644
--- a/northd/lb.h
+++ b/northd/lb.h
@@ -74,6 +74,9 @@ struct ovn_northd_lb {
     /* Indicates if the load balancer has health checks configured. */
     bool health_checks;
 
+    /* Indicates if distributed option is enabled for load balancer. */
+    bool is_distributed;
+
     char *hairpin_snat_ip;
 };
 
@@ -90,6 +93,7 @@ struct ovn_northd_lb_backend {
     bool health_check;
      /* Set to true if port does not locate in local AZ. */
     bool remote_backend;
+    bool distributed_backend;
     /* Logical port to which the ip belong to. */
     char *logical_port;
     /* Source IP address to be used for service monitoring. */
diff --git a/northd/northd.c b/northd/northd.c
index 074e7ea7e..1e9b45f66 100644
--- a/northd/northd.c
+++ b/northd/northd.c
@@ -557,6 +557,7 @@ ovn_datapath_create(struct hmap *datapaths, const struct 
uuid *key,
     od->localnet_ports = VECTOR_EMPTY_INITIALIZER(struct ovn_port *);
     od->lb_with_stateless_mode = false;
     od->ipam_info_initialized = false;
+    od->is_distributed = false;
     od->tunnel_key = sdp->sb_dp->tunnel_key;
     init_mcast_info_for_datapath(od);
     return od;
@@ -3306,6 +3307,54 @@ ovn_lb_svc_create(struct ovsdb_idl_txn *ovnsb_txn,
     }
 }
 
+static bool
+is_backend_available(const struct ovn_northd_lb *lb,
+                     const struct ovn_lb_backend *backend,
+                     const struct ovn_northd_lb_backend *backend_nb,
+                     const struct svc_monitors_map_data *svc_mons_data)
+{
+    const char *protocol = lb->nlb->protocol;
+    if (!protocol || !protocol[0]) {
+        protocol = "tcp";
+    }
+
+    struct service_monitor_info *mon_info =
+        get_service_mon(svc_mons_data->local_svc_monitors_map,
+                        svc_mons_data->ic_learned_svc_monitors_map,
+                        backend->ip_str,
+                        backend_nb->logical_port,
+                        backend->port,
+                        protocol);
+
+    if (!mon_info) {
+        return false;
+    }
+
+    ovs_assert(mon_info->sbrec_mon);
+
+    if (mon_info->sbrec_mon->status &&
+        strcmp(mon_info->sbrec_mon->status, "online")) {
+        return false;
+    }
+
+    return true;
+}
+
+static inline void
+append_lb_backend_to_action(const struct ovn_lb_backend *backend,
+                            const struct ovn_northd_lb_backend *backend_nb,
+                            bool distributed_mode,
+                            struct ds *action)
+{
+    bool ipv6 = !IN6_IS_ADDR_V4MAPPED(&backend->ip);
+
+    if (distributed_mode) {
+        ds_put_format(action, "\"%s\":", backend_nb->logical_port);
+    }
+    ds_put_format(action, ipv6 ? "[%s]:%"PRIu16"," : "%s:%"PRIu16",",
+                  backend->ip_str, backend->port);
+}
+
 static bool
 build_lb_vip_actions(const struct ovn_northd_lb *lb,
                      const struct ovn_lb_vip *lb_vip,
@@ -3331,9 +3380,11 @@ build_lb_vip_actions(const struct ovn_northd_lb *lb,
         }
     }
 
-    if (lb_vip_nb->lb_health_check) {
-        ds_put_cstr(action, "ct_lb_mark(backends=");
+    ds_put_format(action, "%s", lb->is_distributed
+                  ? "ct_lb_mark_local(backends="
+                  : "ct_lb_mark(backends=");
 
+    if (lb_vip_nb->lb_health_check || lb->is_distributed) {
         size_t i = 0;
         size_t n_active_backends = 0;
         const struct ovn_lb_backend *backend;
@@ -3341,45 +3392,38 @@ build_lb_vip_actions(const struct ovn_northd_lb *lb,
             struct ovn_northd_lb_backend *backend_nb =
                 &lb_vip_nb->backends_nb[i++];
 
-            if (!backend_nb->health_check) {
-                continue;
-            }
-
-            const char *protocol = lb->nlb->protocol;
-            if (!protocol || !protocol[0]) {
-                protocol = "tcp";
+            /* Validation of cases of incorrect parameter
+             * settings at the backend level. */
+            if (lb_vip_nb->lb_health_check &&
+                !backend_nb->health_check) {
+                    continue;
             }
 
-            struct service_monitor_info *mon_info =
-                get_service_mon(svc_mons_data->local_svc_monitors_map,
-                                svc_mons_data->ic_learned_svc_monitors_map,
-                                backend->ip_str,
-                                backend_nb->logical_port,
-                                backend->port,
-                                protocol);
-
-            if (!mon_info) {
+            if (lb->is_distributed &&
+                !backend_nb->distributed_backend ) {
                 continue;
             }
 
-            ovs_assert(mon_info->sbrec_mon);
-            if (mon_info->sbrec_mon->status &&
-                    strcmp(mon_info->sbrec_mon->status, "online")) {
+            if (backend_nb->health_check &&
+                !is_backend_available(lb,
+                                      backend,
+                                      backend_nb,
+                                      svc_mons_data)) {
                 continue;
             }
 
             n_active_backends++;
-            bool ipv6 = !IN6_IS_ADDR_V4MAPPED(&backend->ip);
-            ds_put_format(action, ipv6 ? "[%s]:%"PRIu16"," : "%s:%"PRIu16",",
-                          backend->ip_str, backend->port);
+            append_lb_backend_to_action(backend,
+                                        backend_nb,
+                                        backend_nb->distributed_backend,
+                                        action);
         }
         ds_chomp(action, ',');
 
         drop = !n_active_backends && !lb_vip->empty_backend_rej;
         reject = !n_active_backends && lb_vip->empty_backend_rej;
     } else {
-        ds_put_format(action, "ct_lb_mark(backends=%s",
-                      lb_vip_nb->backend_ips);
+        ds_put_format(action, "%s", lb_vip_nb->backend_ips);
     }
 
     if (reject) {
@@ -3416,6 +3460,20 @@ build_lb_vip_actions(const struct ovn_northd_lb *lb,
     return reject;
 }
 
+static inline void
+handle_od_lb_datapath_modes(struct ovn_datapath *od,
+                            struct ovn_lb_datapaths *lb_dps,
+                            bool od_is_switch)
+{
+    if (od_is_switch && od->lb_with_stateless_mode) {
+        hmapx_add(&lb_dps->ls_lb_with_stateless_mode, od);
+    }
+
+    if (!od_is_switch && lb_dps->lb->is_distributed) {
+        od->is_distributed = true;
+    }
+}
+
 static void
 build_lb_datapaths(const struct hmap *lbs, const struct hmap *lb_groups,
                    struct ovn_datapaths *ls_datapaths,
@@ -3458,9 +3516,7 @@ build_lb_datapaths(const struct hmap *lbs, const struct 
hmap *lb_groups,
             lb_dps = ovn_lb_datapaths_find(lb_datapaths_map, lb_uuid);
             ovs_assert(lb_dps);
             ovn_lb_datapaths_add_ls(lb_dps, 1, &od, ods_size(ls_datapaths));
-            if (od->lb_with_stateless_mode) {
-                hmapx_add(&lb_dps->ls_lb_with_stateless_mode, od);
-            }
+            handle_od_lb_datapath_modes(od, lb_dps, true);
         }
 
         for (size_t i = 0; i < od->nbs->n_load_balancer_group; i++) {
@@ -3493,6 +3549,7 @@ build_lb_datapaths(const struct hmap *lbs, const struct 
hmap *lb_groups,
                 &od->nbr->load_balancer[i]->header_.uuid;
             lb_dps = ovn_lb_datapaths_find(lb_datapaths_map, lb_uuid);
             ovs_assert(lb_dps);
+            handle_od_lb_datapath_modes(od, lb_dps, false);
             ovn_lb_datapaths_add_lr(lb_dps, 1, &od, ods_size(lr_datapaths));
         }
     }
@@ -3847,6 +3904,7 @@ sync_pb_for_lrp(struct ovn_port *op,
 
         bool always_redirect =
             !lr_stateful_rec->lrnat_rec->has_distributed_nat &&
+            !lr_stateful_rec->has_distributed_lb &&
             !l3dgw_port_has_associated_vtep_lports(op->primary_port);
 
         const char *redirect_type = smap_get(&op->nbrp->options,
@@ -5427,10 +5485,7 @@ northd_handle_lb_data_changes(struct tracked_lb_data 
*trk_lb_data,
             lb_dps = ovn_lb_datapaths_find(lb_datapaths_map, &uuidnode->uuid);
             ovs_assert(lb_dps);
             ovn_lb_datapaths_add_ls(lb_dps, 1, &od, ods_size(ls_datapaths));
-
-            if (od->lb_with_stateless_mode) {
-                hmapx_add(&lb_dps->ls_lb_with_stateless_mode, od);
-            }
+            handle_od_lb_datapath_modes(od, lb_dps, true);
 
             /* Add the lb to the northd tracked data. */
             hmapx_add(&nd_changes->trk_lbs.crupdated, lb_dps);
@@ -5469,6 +5524,7 @@ northd_handle_lb_data_changes(struct tracked_lb_data 
*trk_lb_data,
             lb_dps = ovn_lb_datapaths_find(lb_datapaths_map, &uuidnode->uuid);
             ovs_assert(lb_dps);
             ovn_lb_datapaths_add_lr(lb_dps, 1, &od, ods_size(lr_datapaths));
+            handle_od_lb_datapath_modes(od, lb_dps, false);
 
             /* Add the lb to the northd tracked data. */
             hmapx_add(&nd_changes->trk_lbs.crupdated, lb_dps);
@@ -10821,8 +10877,13 @@ build_lswitch_ip_unicast_lookup(struct ovn_port *op,
                          : debug_drop_action();
 
     if (lsp_is_router(op->nbsp) && op->peer && op->peer->nbrp) {
+        /* Distributed gateway ports default to centralized mode.
+         * They operate in distributed mode only when configured
+         * on their bound router. */
+        bool peer_lrp_is_centralized = !op->peer->od->is_distributed;
+
         /* For ports connected to logical routers add flows to bypass the
-         * broadcast flooding of ARP/ND requests in table 19. We direct the
+         * broadcast flooding of ARP/ND requests in table 22. We direct the
          * requests only to the router port that owns the IP address.
          */
         build_lswitch_rport_arp_req_flows(op->peer, op->od, op, lflows,
@@ -10837,7 +10898,8 @@ build_lswitch_ip_unicast_lookup(struct ovn_port *op,
             ds_put_format(match, "eth.dst == %s", op->peer->lrp_networks.ea_s);
         }
 
-        if (!vector_is_empty(&op->peer->od->l3dgw_ports) &&
+        if (peer_lrp_is_centralized &&
+            !vector_is_empty(&op->peer->od->l3dgw_ports) &&
             !vector_is_empty(&op->od->localnet_ports)) {
             add_lrp_chassis_resident_check(op->peer, match);
         } else if (op->cr_port) {
@@ -12571,6 +12633,13 @@ build_distr_lrouter_nat_flows_for_lb(struct 
lrouter_nat_lb_flows_ctx *ctx,
     size_t new_match_len = ctx->new_match->length;
     size_t undnat_match_len = ctx->undnat_match->length;
 
+    bool lb_is_centralized = !ctx->lb->is_distributed;
+
+    /* If load balancer is distributed, then the response traffic
+     * must be returned through the distributed port.*/
+    const char *gw_outport = lb_is_centralized ? dgp->cr_port->json_key
+                                               : dgp->json_key;
+
     /* (NOTE) dnat_action: Add the first LB backend IP as a destination
      * action of the lr_in_dnat NAT rule. Including the backend IP is useful
      * for accepting packets coming from a chassis that does not have
@@ -12605,8 +12674,9 @@ build_distr_lrouter_nat_flows_for_lb(struct 
lrouter_nat_lb_flows_ctx *ctx,
         meter = copp_meter_get(COPP_REJECT, od->nbr->copp, ctx->meter_groups);
     }
 
-    if (!vector_is_empty(&ctx->lb_vip->backends) ||
-        !ctx->lb_vip->empty_backend_rej) {
+    if (lb_is_centralized &&
+        (!vector_is_empty(&ctx->lb_vip->backends) ||
+        !ctx->lb_vip->empty_backend_rej)) {
         ds_put_format(ctx->new_match, " && is_chassis_resident(%s)",
                       dgp->cr_port->json_key);
     }
@@ -12653,8 +12723,8 @@ build_distr_lrouter_nat_flows_for_lb(struct 
lrouter_nat_lb_flows_ctx *ctx,
      */
     ds_put_format(ctx->undnat_match, ") && outport == %s", dgp->json_key);
     ds_clear(ctx->gw_redir_action);
-    ds_put_format(ctx->gw_redir_action, "outport = %s; next;",
-                  dgp->cr_port->json_key);
+    ds_put_format(ctx->gw_redir_action,
+                  "outport = %s; next;", gw_outport);
 
     ovn_lflow_add_with_hint(ctx->lflows, od, S_ROUTER_IN_GW_REDIRECT,
                             200, ds_cstr(ctx->undnat_match),
@@ -12663,9 +12733,14 @@ build_distr_lrouter_nat_flows_for_lb(struct 
lrouter_nat_lb_flows_ctx *ctx,
                             lflow_ref);
     ds_truncate(ctx->undnat_match, undnat_match_len);
 
-    ds_put_format(ctx->undnat_match, ") && (inport == %s || outport == %s)"
-                  " && is_chassis_resident(%s)", dgp->json_key, dgp->json_key,
-                  dgp->cr_port->json_key);
+    ds_put_format(ctx->undnat_match, ") && (inport == %s || outport == %s)",
+                  dgp->json_key, dgp->json_key);
+
+    if (lb_is_centralized) {
+        ds_put_format(ctx->undnat_match, " && is_chassis_resident(%s)",
+                      dgp->cr_port->json_key);
+    }
+
     /* Use the LB protocol as matching criteria for out undnat and snat when
      * creating LBs with stateless NAT. */
     if (stateless_nat) {
@@ -13994,6 +14069,10 @@ build_gateway_mtu_flow(struct lflow_table *lflows, 
struct ovn_port *op,
 static bool
 consider_l3dgw_port_is_centralized(struct ovn_port *op)
 {
+    if (op->od->is_distributed) {
+        return false;
+    }
+
     if (l3dgw_port_has_associated_vtep_lports(op)) {
         return false;
     }
@@ -16215,7 +16294,7 @@ build_ipv6_input_flows_for_lrouter_port(
      * router's own IP address. */
     for (int i = 0; i < op->lrp_networks.n_ipv6_addrs; i++) {
         ds_clear(match);
-        if (lrp_is_l3dgw(op)) {
+        if (lrp_is_l3dgw(op) && !op->od->is_distributed) {
             /* Traffic with eth.src = l3dgw_port->lrp_networks.ea_s
              * should only be sent from the gateway chassi, so that
              * upstream MAC learning points to the gateway chassis.
@@ -16492,13 +16571,15 @@ build_lrouter_ipv4_ip_input(struct ovn_port *op,
 
     /* ARP reply.  These flows reply to ARP requests for the router's own
      * IP address. */
+    bool od_distributed = op->od->is_distributed;
     for (int i = 0; i < op->lrp_networks.n_ipv4_addrs; i++) {
         ds_clear(match);
         ds_put_format(match, "arp.spa == %s/%u",
                       op->lrp_networks.ipv4_addrs[i].network_s,
                       op->lrp_networks.ipv4_addrs[i].plen);
 
-        if (!vector_is_empty(&op->od->l3dgw_ports) && op->peer
+        if (!od_distributed &&
+            !vector_is_empty(&op->od->l3dgw_ports) && op->peer
             && !vector_is_empty(&op->peer->od->localnet_ports)) {
             add_lrp_chassis_resident_check(op, match);
         }
diff --git a/northd/northd.h b/northd/northd.h
index 2869ea97e..20782e908 100644
--- a/northd/northd.h
+++ b/northd/northd.h
@@ -453,6 +453,11 @@ struct ovn_datapath {
     /* Indicates that the LS has valid vni associated with it. */
     bool has_evpn_vni;
 
+    /* True if datapath has some distributed dependencies.
+     * Currently, this only applies to load balancers attached to datapath
+     * with distributed mode enabled. */
+    bool is_distributed;
+
     /* OVN northd only needs to know about logical router gateway ports for
      * NAT/LB on a distributed router.  The "distributed gateway ports" are
      * populated only when there is a gateway chassis or ha chassis group
diff --git a/ovn-nb.xml b/ovn-nb.xml
index b5fe44e53..a83763814 100644
--- a/ovn-nb.xml
+++ b/ovn-nb.xml
@@ -2378,13 +2378,15 @@
         <p>
           Maps from endpoint IP to a colon-separated pair of logical port name
           and source IP,
-          e.g. <code><var>port_name</var>:<var>sourc_ip</var></code> for IPv4.
+          e.g. <code><var>port_name</var>:<var>source_ip</var></code> for IPv4.
           Health checks are sent to this port with the specified source IP.
           For IPv6 square brackets must be used around IP address, e.g:
-          <code><var>port_name</var>:<var>[sourc_ip]</var></code>
+          <code><var>port_name</var>:<var>[source_ip]</var></code>
           Remote endpoint:
           Specify :target_zone_name at the end of the above syntax to create
           remote health checks in a specific zone.
+          For distributed load balancers - ip_port_mappings is required.
+          In the absence of health checks - source_ip is optional.
         </p>
 
         <p>
@@ -2587,6 +2589,15 @@ or
         traffic may be dropped in scenarios where we have different chassis
         for each DGP. This option is set to <code>false</code> by default.
       </column>
+
+      <column name="options" key="distributed">
+        Enabling this option distributes load balancing across compute nodes,
+        where traffic is routed only to local backends. To ensure proper
+        operation, you must configure <ref column="ip_port_mappings"/> first.
+        This option is only supported for load balancers that are attached to
+        logical routers.
+      </column>
+
     </group>
   </table>
 
diff --git a/tests/ovn-northd.at b/tests/ovn-northd.at
index 931064fe6..51b40941e 100644
--- a/tests/ovn-northd.at
+++ b/tests/ovn-northd.at
@@ -18095,6 +18095,9 @@ ovn_start
 # ip_port_mappings syntax: ip:lport_name:src_ip:<az_name>(for remote lports)
 
 check ovn-nbctl ls-add ls1
+check ovn-nbctl lr-add lr1
+
+ovn-appctl -t ovn-northd vlog/disable-rate-limit
 
 check ovn-nbctl lb-add lb1_ipv4 1.1.1.1:80 
192.168.0.1:10880,192.168.0.2:10880,192.168.0.3:10880
 AT_CHECK([ovn-nbctl --wait=sb \
@@ -18164,6 +18167,154 @@ check ovn-nbctl set load_balancer lb1_ipv4 
ip_port_mappings:192.168.0.1=lport1:1
 check_row_count sb:Service_Monitor 0
 
 OVS_WAIT_UNTIL([grep "Empty AZ name specified" northd/ovn-northd.log])
+
+check ovn-nbctl lb-del lb1_ipv4
+
+# Check correct setup of distributed load balancers.
+echo > northd/ovn-northd.log
+check ovn-nbctl lb-add lb_distubuted 1.1.1.1:80 
192.168.0.1:10880,192.168.0.2:10880
+check ovn-nbctl lr-lb-add lr1 lb_distubuted
+check ovn-nbctl set load_balancer lb_distubuted options:distributed=true
+
+# Check that load balancer does not work in a distributed mode - there is no 
ip_port_mappings setting
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip4 && ip4.dst == 1.1.1.1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(drop;)
+])
+
+# Check that the load balancer has only one backend available since the only 
one backend has ip_port_mappings
+check ovn-nbctl set load_balancer lb_distubuted 
ip_port_mappings:192.168.0.1=lport1
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip4 && ip4.dst == 1.1.1.1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":192.168.0.1:10880);)
+])
+
+check ovn-nbctl set load_balancer lb_distubuted 
ip_port_mappings:192.168.0.2=lport2
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip4 && ip4.dst == 1.1.1.1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":192.168.0.1:10880,"lport2":192.168.0.2:10880);)
+])
+
+# Check if health check is configured, ip_port_mappings must be provided.
+AT_CHECK([ovn-nbctl --wait=sb \
+          -- --id=@hc create Load_Balancer_Health_Check vip="1.1.1.1\:80" \
+             options:failure_count=100 \
+          -- add Load_Balancer lb_distubuted health_check @hc | uuidfilt], 
[0], [<0>
+])
+
+ovn-sbctl lflow-list lr1 > lr1_lflow
+OVS_WAIT_UNTIL([grep "Expected ':' separator for:" northd/ovn-northd.log])
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip4 && ip4.dst == 1.1.1.1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(drop;)
+])
+
+check ovn-nbctl lb-del lb_distubuted
+echo > northd/ovn-northd.log
+
+# ipv6 configuration
+check ovn-nbctl lb-add lb1 [[2001::a]]:80 [[2001::3]]:80,[[2002::3]]:80
+
+check_uuid ovn-nbctl --wait=sb -- --id=@hc create \
+Load_Balancer_Health_Check vip="\[\[2001\:\:a\]\]\:80" -- add Load_Balancer . \
+health_check @hc
+
+check_row_count sb:Service_Monitor 0
+check ovn-nbctl --wait=sb set load_balancer . 
ip_port_mappings:\"[[2001::3]]\"=\"lport1:[[2001::2]]\"
+
+check_row_count sb:Service_Monitor 1
+ovn-sbctl list service_monitor
+check_column "2001::3" sb:Service_Monitor ip logical_port=lport1
+check_column 80 sb:Service_Monitor port logical_port=lport1
+check_column tcp sb:Service_Monitor protocol logical_port=lport1
+check_column "2001::2" sb:Service_Monitor src_ip logical_port=lport1
+check_column false sb:Service_Monitor ic_learned logical_port=lport1
+check_column false sb:Service_Monitor remote logical_port=lport1
+check_column "" sb:Service_Monitor logical_input_port logical_port=lport1
+
+# Empty src_ip.
+check ovn-nbctl clear load_balancer lb1 ip_port_mappings
+check ovn-nbctl --wait=sb set load_balancer . 
ip_port_mappings:\"[[2001::3]]\"=\"lport1:\"
+OVS_WAIT_UNTIL([grep "Invalid svc mon src IP" northd/ovn-northd.log])
+check_row_count sb:Service_Monitor 0
+echo > northd/ovn-northd.log
+
+# Uncorrect ip_address.
+check ovn-nbctl --wait=sb set load_balancer . 
ip_port_mappings:\"[[invalid]]\"=\"lport1:\"
+OVS_WAIT_UNTIL([grep "bad IP address" northd/ovn-northd.log])
+echo > northd/ovn-northd.log
+
+check ovn-nbctl --wait=sb set load_balancer . 
ip_port_mappings:\"[[2001::3]]\"=\"lport1:invalid\"
+OVS_WAIT_UNTIL([grep "bad IP address" northd/ovn-northd.log])
+echo > northd/ovn-northd.log
+
+check ovn-nbctl --wait=sb set load_balancer . 
ip_port_mappings:\"[[2001::3]]\"=\"lport1:[[2001::2]]:az_name\"
+check_row_count sb:Service_Monitor 1
+ovn-sbctl list service_monitor
+check_column "2001::3" sb:Service_Monitor ip logical_port=lport1
+check_column 80 sb:Service_Monitor port logical_port=lport1
+check_column tcp sb:Service_Monitor protocol logical_port=lport1
+check_column "2001::2" sb:Service_Monitor src_ip logical_port=lport1
+check_column false sb:Service_Monitor ic_learned logical_port=lport1
+check_column true sb:Service_Monitor remote logical_port=lport1
+check_column "" sb:Service_Monitor logical_input_port logical_port=lport1
+
+uuid=$(ovn-sbctl -d bare --no-headings --columns _uuid find Service_Monitor 
logical_port=lport1)
+
+# Check az_name presence in options.
+AT_CHECK([ovn-sbctl get Service_Monitor ${uuid} options:az-name],
+[0], [az_name
+])
+
+check ovn-nbctl --wait=sb set load_balancer . 
ip_port_mappings:\"[[2001::3]]\"=\"lport1:[[2001::2]]:\"
+check_row_count sb:Service_Monitor 0
+OVS_WAIT_UNTIL([grep "Empty AZ name specified" northd/ovn-northd.log])
+
+echo > northd/ovn-northd.log
+check ovn-nbctl lb-del lb1
+
+# Check correct setup of distributed load balancers.
+check ovn-nbctl lb-add lb_distubuted [[2001::a]]:80 
[[2001::3]]:80,[[2002::3]]:80
+check ovn-nbctl lr-lb-add lr1 lb_distubuted
+check ovn-nbctl set load_balancer lb_distubuted options:distributed=true
+
+# Check that load balancer does not work in a distributed mode - there is no 
ip_port_mappings setting
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2001::a && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(drop;)
+])
+
+echo > northd/ovn-northd.log
+check ovn-nbctl set load_balancer . ip_port_mappings:\"[[2001::3]]\"=\"lport1\"
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2001::a && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":[[2001::3]]:80);)
+])
+
+echo > northd/ovn-northd.log
+check ovn-nbctl set load_balancer . ip_port_mappings:\"[[2002::3]]\"=\"lport2\"
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2001::a && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":[[2001::3]]:80,"lport2":[[2002::3]]:80);)
+])
+
+echo > northd/ovn-northd.log
+check_uuid ovn-nbctl --wait=sb -- --id=@hc create \
+Load_Balancer_Health_Check vip="\[\[2001\:\:a\]\]\:80" -- add Load_Balancer . \
+health_check @hc
+OVS_WAIT_UNTIL([grep "Expected ':' separator for:" northd/ovn-northd.log])
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2001::a && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(drop;)
+])
+
+check ovn-nbctl --wait=sb set load_balancer . 
ip_port_mappings:\"[[2001::3]]\"=\"lport1:[[2001::2]]\"
+ovn-sbctl lflow-list lr1 > lr1_lflow
+AT_CHECK([cat lr1_lflow | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2001::a && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":[[2001::3]]:80);)
+])
+
+check ovn-nbctl lb-del lb_distubuted
+
 OVN_CLEANUP_NORTHD
 AT_CLEANUP
 ])
@@ -18914,3 +19065,207 @@ wait_row_count Igmp_Group 0 address=mrouters
 OVN_CLEANUP_NORTHD
 AT_CLEANUP
 ])
+
+OVN_FOR_EACH_NORTHD_NO_HV([
+AT_SETUP([Distributed lb: logical-flow test - IPv4/IPv6 case])
+ovn_start
+
+# (1) Create two load balancers, IPv4 and IPv6, attach them to a router that 
has a distributed gateway port.
+# (2) Set the gateway to an existing gateway - verify that all router flows 
are centralized (arp/nd).
+# (3) Change the gateway to a non-existent one, make one load balancer 
distributed - verify that all router flows for the router become distributed.
+# (4) Verify that flows for the distributed load balancer are distributed, and 
for the second load balancer are centralized.
+# (5) Make the second load balancer distributed, verify its flows.
+# (6) Remove the option from one load balancer, verify that the logic is 
maintained that if at least one load balancer has the option - the entire 
router is distributed.
+
+check ovn-nbctl ls-add outside
+
+check ovn-nbctl lsp-add outside outside \
+      -- lsp-set-addresses outside unknown \
+      -- lsp-set-type outside localnet
+
+check ovn-nbctl --wait=sb set Logical_Switch_Port outside tag_request=2
+
+check ovn-nbctl lsp-add outside outside-down \
+      -- lsp-set-type outside-down router \
+      -- lsp-set-addresses outside-down router \
+      -- lsp-set-options outside-down router-port=lr1-up
+
+check ovn-nbctl lr-add lr1 \
+      -- lrp-add lr1 lr1-up 11:11:11:11:11:11 169.254.0.1/24 
2001:db8:abcd:0002::bad/64 \
+      -- lrp-add lr1 lr1-down 12:12:12:12:12:12 192.168.0.1/24 
2001:db8:abcd:0001::c0fe/64
+
+check ovn-nbctl ls-add ls1 \
+      -- lsp-add ls1 lport1 \
+      -- lsp-set-addresses lport1 "13:13:13:13:13:13 192.168.0.101" \
+      -- lsp-add ls1 lport2 \
+      -- lsp-set-addresses lport2 "14:14:14:14:14:14 192.168.0.102"
+
+check ovn-nbctl lsp-add ls1 ls1-up \
+      -- lsp-set-type ls1-up router \
+      -- lsp-set-addresses ls1-up router \
+      -- lsp-set-options ls1-up router-port=lr1-down
+
+check ovn-nbctl --wait=sb sync
+
+check ovn-nbctl ha-chassis-group-add gateway
+check ovn-nbctl ha-chassis-group-add-chassis gateway hv1 1
+ha_g_uuid=$(fetch_column nb:HA_Chassis_Group _uuid name=gateway)
+lr1_up_uuid=$(fetch_column nb:Logical_Router_Port _uuid name=lr1-up)
+check ovn-nbctl set logical_router_port $lr1_up_uuid 
ha_chassis_group=$ha_g_uuid
+
+check ovn-nbctl --wait=sb sync
+
+check ovn-nbctl lb-add lb1_ipv4 1.1.1.1:80 
192.168.0.101:10880,192.168.0.102:10880
+check ovn-nbctl set Load_Balancer lb1_ipv4 
ip_port_mappings:192.168.0.101=lport1:192.168.0.199
+check ovn-nbctl set Load_Balancer lb1_ipv4 
ip_port_mappings:192.168.0.102=lport2:192.168.0.199
+check ovn-nbctl lr-lb-add lr1 lb1_ipv4
+check ovn-nbctl --wait=sb sync
+
+check ovn-nbctl lb-add lb1_ipv6 [[2000::1]]:80  [[2001:db8:abcd:1::2]]:10882
+check ovn-nbctl set Load_Balancer lb1_ipv6 
ip_port_mappings:\"[[2001:db8:abcd:1::2]]\"=\"lport1\"
+check ovn-nbctl lr-lb-add lr1 lb1_ipv6
+check ovn-nbctl --wait=sb sync
+
+ovn-sbctl lflow-list lr1 > lr1_lflows_before
+ovn-sbctl lflow-list outside > outside_lflows_before
+
+AT_CHECK([cat outside_lflows_before | grep ls_in_l2_lkup | grep priority=50 | 
ovn_strip_lflows], [0], [dnl
+  table=??(ls_in_l2_lkup      ), priority=50   , match=(eth.dst == 
11:11:11:11:11:11 && is_chassis_resident("cr-lr1-up")), action=(outport = 
"outside-down"; output;)
+])
+
+AT_CHECK([cat lr1_lflows_before | grep lr_in_ip_input | grep priority=90 | 
grep 169.254.0.1 | ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_ip_input     ), priority=90   , match=(inport == "lr1-up" && 
arp.op == 1 && arp.tpa == 169.254.0.1 && arp.spa == 169.254.0.0/24 && 
is_chassis_resident("cr-lr1-up")), action=(eth.dst = eth.src; eth.src = 
xreg0[[0..47]]; arp.op = 2; /* ARP reply */ arp.tha = arp.sha; arp.sha = 
xreg0[[0..47]]; arp.tpa <-> arp.spa; outport = inport; flags.loopback = 1; 
output;)
+  table=??(lr_in_ip_input     ), priority=90   , match=(ip4.dst == 169.254.0.1 
&& icmp4.type == 8 && icmp4.code == 0), action=(ip4.dst <-> ip4.src; ip.ttl = 
255; icmp4.type = 0; flags.loopback = 1; next; )
+])
+
+AT_CHECK([cat lr1_lflows_before | grep lr_in_ip_input | grep priority=90 | 
grep 2001:db8:abcd:2::bad | ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_ip_input     ), priority=90   , match=(inport == "lr1-up" && 
ip6.dst == {2001:db8:abcd:2::bad, ff02::1:ff00:bad} && nd_ns && nd.target == 
2001:db8:abcd:2::bad && is_chassis_resident("cr-lr1-up")), action=(nd_na_router 
{ eth.src = xreg0[[0..47]]; ip6.src = nd.target; nd.tll = xreg0[[0..47]]; 
outport = inport; flags.loopback = 1; output; };)
+  table=??(lr_in_ip_input     ), priority=90   , match=(ip6.dst == 
{2001:db8:abcd:2::bad, fe80::1311:11ff:fe11:1111} && icmp6.type == 128 && 
icmp6.code == 0), action=(ip6.dst <-> ip6.src; ip.ttl = 255; icmp6.type = 129; 
flags.loopback = 1; next; )
+])
+
+AT_CHECK([cat lr1_lflows_before | grep lr_in_admission | grep  priority=50 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_admission    ), priority=50   , match=(eth.dst == 
11:11:11:11:11:11 && inport == "lr1-up" && is_chassis_resident("cr-lr1-up")), 
action=(xreg0[[0..47]] = 11:11:11:11:11:11; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.dst == 
12:12:12:12:12:12 && inport == "lr1-down"), action=(xreg0[[0..47]] = 
12:12:12:12:12:12; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.mcast && inport == 
"lr1-down"), action=(xreg0[[0..47]] = 12:12:12:12:12:12; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.mcast && inport == 
"lr1-up"), action=(xreg0[[0..47]] = 11:11:11:11:11:11; next;)
+])
+
+AT_CHECK([cat lr1_lflows_before | grep lr_out_undnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_out_undnat      ), priority=120  , match=(ip4 && ((ip4.src == 
192.168.0.101 && tcp.src == 10880) || (ip4.src == 192.168.0.102 && tcp.src == 
10880)) && (inport == "lr1-up" || outport == "lr1-up") && 
is_chassis_resident("cr-lr1-up")), action=(ct_dnat;)
+  table=??(lr_out_undnat      ), priority=120  , match=(ip6 && ((ip6.src == 
2001:db8:abcd:1::2 && tcp.src == 10882)) && (inport == "lr1-up" || outport == 
"lr1-up") && is_chassis_resident("cr-lr1-up")), action=(ct_dnat;)
+])
+
+AT_CHECK([cat lr1_lflows_before | grep lr_in_gw_redirect | ovn_strip_lflows], 
[0], [dnl
+  table=??(lr_in_gw_redirect  ), priority=0    , match=(1), action=(next;)
+  table=??(lr_in_gw_redirect  ), priority=200  , match=(ip4 && ((ip4.src == 
192.168.0.101 && tcp.src == 10880) || (ip4.src == 192.168.0.102 && tcp.src == 
10880)) && outport == "lr1-up"), action=(outport = "cr-lr1-up"; next;)
+  table=??(lr_in_gw_redirect  ), priority=200  , match=(ip6 && ((ip6.src == 
2001:db8:abcd:1::2 && tcp.src == 10882)) && outport == "lr1-up"), 
action=(outport = "cr-lr1-up"; next;)
+  table=??(lr_in_gw_redirect  ), priority=50   , match=(outport == "lr1-up"), 
action=(outport = "cr-lr1-up"; next;)
+])
+
+AT_CHECK([cat lr1_lflows_before | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip4 && ip4.dst == 1.1.1.1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80 && 
is_chassis_resident("cr-lr1-up")), 
action=(ct_lb_mark(backends=192.168.0.101:10880,192.168.0.102:10880);)
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2000::1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80 && 
is_chassis_resident("cr-lr1-up")), 
action=(ct_lb_mark(backends=[[2001:db8:abcd:1::2]]:10882);)
+])
+
+check ovn-nbctl clear logical_router_port $lr1_up_uuid ha_chassis_group
+check ovn-nbctl ha-chassis-group-del gateway
+check ovn-nbctl ha-chassis-group-add gateway2
+check ovn-nbctl ha-chassis-group-add-chassis gateway2 test 1
+ha_g_uuid=$(fetch_column nb:HA_Chassis_Group _uuid name=gateway2)
+lr1_up_uuid=$(fetch_column nb:Logical_Router_Port _uuid name=lr1-up)
+check ovn-nbctl set logical_router_port $lr1_up_uuid 
ha_chassis_group=$ha_g_uuid
+
+check ovn-nbctl set load_balancer lb1_ipv4 options:distributed=true
+check ovn-nbctl --wait=hv sync
+
+ovn-sbctl lflow-list outside > outside_lflows_after
+ovn-sbctl lflow-list lr1 > lr1_lflows_after
+
+AT_CHECK([cat outside_lflows_after | grep ls_in_l2_lkup | grep priority=50 | 
ovn_strip_lflows], [0], [dnl
+  table=??(ls_in_l2_lkup      ), priority=50   , match=(eth.dst == 
11:11:11:11:11:11), action=(outport = "outside-down"; output;)
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_ip_input | grep priority=90 | grep 
169.254.0.1 | ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_ip_input     ), priority=90   , match=(inport == "lr1-up" && 
arp.op == 1 && arp.tpa == 169.254.0.1 && arp.spa == 169.254.0.0/24), 
action=(eth.dst = eth.src; eth.src = xreg0[[0..47]]; arp.op = 2; /* ARP reply 
*/ arp.tha = arp.sha; arp.sha = xreg0[[0..47]]; arp.tpa <-> arp.spa; outport = 
inport; flags.loopback = 1; output;)
+  table=??(lr_in_ip_input     ), priority=90   , match=(ip4.dst == 169.254.0.1 
&& icmp4.type == 8 && icmp4.code == 0), action=(ip4.dst <-> ip4.src; ip.ttl = 
255; icmp4.type = 0; flags.loopback = 1; next; )
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_ip_input | grep priority=90 | grep 
2001:db8:abcd:2::bad | ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_ip_input     ), priority=90   , match=(inport == "lr1-up" && 
ip6.dst == {2001:db8:abcd:2::bad, ff02::1:ff00:bad} && nd_ns && nd.target == 
2001:db8:abcd:2::bad), action=(nd_na_router { eth.src = xreg0[[0..47]]; ip6.src 
= nd.target; nd.tll = xreg0[[0..47]]; outport = inport; flags.loopback = 1; 
output; };)
+  table=??(lr_in_ip_input     ), priority=90   , match=(ip6.dst == 
{2001:db8:abcd:2::bad, fe80::1311:11ff:fe11:1111} && icmp6.type == 128 && 
icmp6.code == 0), action=(ip6.dst <-> ip6.src; ip.ttl = 255; icmp6.type = 129; 
flags.loopback = 1; next; )
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_admission | grep priority=50 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_admission    ), priority=50   , match=(eth.dst == 
11:11:11:11:11:11 && inport == "lr1-up"), action=(xreg0[[0..47]] = 
11:11:11:11:11:11; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.dst == 
12:12:12:12:12:12 && inport == "lr1-down"), action=(xreg0[[0..47]] = 
12:12:12:12:12:12; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.mcast && inport == 
"lr1-down"), action=(xreg0[[0..47]] = 12:12:12:12:12:12; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.mcast && inport == 
"lr1-up"), action=(xreg0[[0..47]] = 11:11:11:11:11:11; next;)
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_out_undnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_out_undnat      ), priority=120  , match=(ip4 && ((ip4.src == 
192.168.0.101 && tcp.src == 10880) || (ip4.src == 192.168.0.102 && tcp.src == 
10880)) && (inport == "lr1-up" || outport == "lr1-up")), action=(ct_dnat;)
+  table=??(lr_out_undnat      ), priority=120  , match=(ip6 && ((ip6.src == 
2001:db8:abcd:1::2 && tcp.src == 10882)) && (inport == "lr1-up" || outport == 
"lr1-up") && is_chassis_resident("cr-lr1-up")), action=(ct_dnat;)
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_gw_redirect | ovn_strip_lflows], 
[0], [dnl
+  table=??(lr_in_gw_redirect  ), priority=0    , match=(1), action=(next;)
+  table=??(lr_in_gw_redirect  ), priority=200  , match=(ip4 && ((ip4.src == 
192.168.0.101 && tcp.src == 10880) || (ip4.src == 192.168.0.102 && tcp.src == 
10880)) && outport == "lr1-up"), action=(outport = "lr1-up"; next;)
+  table=??(lr_in_gw_redirect  ), priority=200  , match=(ip6 && ((ip6.src == 
2001:db8:abcd:1::2 && tcp.src == 10882)) && outport == "lr1-up"), 
action=(outport = "cr-lr1-up"; next;)
+  table=??(lr_in_gw_redirect  ), priority=50   , match=(outport == "lr1-up"), 
action=(outport = "cr-lr1-up"; next;)
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip4 && ip4.dst == 1.1.1.1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":192.168.0.101:10880,"lport2":192.168.0.102:10880);)
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2000::1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80 && 
is_chassis_resident("cr-lr1-up")), 
action=(ct_lb_mark(backends=[[2001:db8:abcd:1::2]]:10882);)
+])
+
+check ovn-nbctl set load_balancer lb1_ipv6 options:distributed=true
+check ovn-nbctl --wait=hv sync
+
+ovn-sbctl lflow-list outside > outside_lflows_after
+ovn-sbctl lflow-list lr1 > lr1_lflows_after
+
+AT_CHECK([cat lr1_lflows_after | grep lr_out_undnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_out_undnat      ), priority=120  , match=(ip4 && ((ip4.src == 
192.168.0.101 && tcp.src == 10880) || (ip4.src == 192.168.0.102 && tcp.src == 
10880)) && (inport == "lr1-up" || outport == "lr1-up")), action=(ct_dnat;)
+  table=??(lr_out_undnat      ), priority=120  , match=(ip6 && ((ip6.src == 
2001:db8:abcd:1::2 && tcp.src == 10882)) && (inport == "lr1-up" || outport == 
"lr1-up")), action=(ct_dnat;)
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_gw_redirect | ovn_strip_lflows], 
[0], [dnl
+  table=??(lr_in_gw_redirect  ), priority=0    , match=(1), action=(next;)
+  table=??(lr_in_gw_redirect  ), priority=200  , match=(ip4 && ((ip4.src == 
192.168.0.101 && tcp.src == 10880) || (ip4.src == 192.168.0.102 && tcp.src == 
10880)) && outport == "lr1-up"), action=(outport = "lr1-up"; next;)
+  table=??(lr_in_gw_redirect  ), priority=200  , match=(ip6 && ((ip6.src == 
2001:db8:abcd:1::2 && tcp.src == 10882)) && outport == "lr1-up"), 
action=(outport = "lr1-up"; next;)
+  table=??(lr_in_gw_redirect  ), priority=50   , match=(outport == "lr1-up"), 
action=(outport = "cr-lr1-up"; next;)
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_dnat | grep priority=120 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip4 && ip4.dst == 1.1.1.1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":192.168.0.101:10880,"lport2":192.168.0.102:10880);)
+  table=??(lr_in_dnat         ), priority=120  , match=(ct.new && !ct.rel && 
ip6 && ip6.dst == 2000::1 && reg1[[16..23]] == 6 && reg1[[0..15]] == 80), 
action=(ct_lb_mark_local(backends="lport1":[[2001:db8:abcd:1::2]]:10882);)
+])
+
+check ovn-nbctl set load_balancer lb1_ipv6 options:distributed=false
+check ovn-nbctl --wait=hv sync
+
+AT_CHECK([cat outside_lflows_after | grep ls_in_l2_lkup | grep priority=50 | 
ovn_strip_lflows], [0], [dnl
+  table=??(ls_in_l2_lkup      ), priority=50   , match=(eth.dst == 
11:11:11:11:11:11), action=(outport = "outside-down"; output;)
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_ip_input | grep priority=90 | grep 
169.254.0.1 | ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_ip_input     ), priority=90   , match=(inport == "lr1-up" && 
arp.op == 1 && arp.tpa == 169.254.0.1 && arp.spa == 169.254.0.0/24), 
action=(eth.dst = eth.src; eth.src = xreg0[[0..47]]; arp.op = 2; /* ARP reply 
*/ arp.tha = arp.sha; arp.sha = xreg0[[0..47]]; arp.tpa <-> arp.spa; outport = 
inport; flags.loopback = 1; output;)
+  table=??(lr_in_ip_input     ), priority=90   , match=(ip4.dst == 169.254.0.1 
&& icmp4.type == 8 && icmp4.code == 0), action=(ip4.dst <-> ip4.src; ip.ttl = 
255; icmp4.type = 0; flags.loopback = 1; next; )
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_ip_input | grep priority=90 | grep 
2001:db8:abcd:2::bad | ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_ip_input     ), priority=90   , match=(inport == "lr1-up" && 
ip6.dst == {2001:db8:abcd:2::bad, ff02::1:ff00:bad} && nd_ns && nd.target == 
2001:db8:abcd:2::bad), action=(nd_na_router { eth.src = xreg0[[0..47]]; ip6.src 
= nd.target; nd.tll = xreg0[[0..47]]; outport = inport; flags.loopback = 1; 
output; };)
+  table=??(lr_in_ip_input     ), priority=90   , match=(ip6.dst == 
{2001:db8:abcd:2::bad, fe80::1311:11ff:fe11:1111} && icmp6.type == 128 && 
icmp6.code == 0), action=(ip6.dst <-> ip6.src; ip.ttl = 255; icmp6.type = 129; 
flags.loopback = 1; next; )
+])
+
+AT_CHECK([cat lr1_lflows_after | grep lr_in_admission | grep priority=50 | 
ovn_strip_lflows], [0], [dnl
+  table=??(lr_in_admission    ), priority=50   , match=(eth.dst == 
11:11:11:11:11:11 && inport == "lr1-up"), action=(xreg0[[0..47]] = 
11:11:11:11:11:11; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.dst == 
12:12:12:12:12:12 && inport == "lr1-down"), action=(xreg0[[0..47]] = 
12:12:12:12:12:12; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.mcast && inport == 
"lr1-down"), action=(xreg0[[0..47]] = 12:12:12:12:12:12; next;)
+  table=??(lr_in_admission    ), priority=50   , match=(eth.mcast && inport == 
"lr1-up"), action=(xreg0[[0..47]] = 11:11:11:11:11:11; next;)
+])
+
+OVN_CLEANUP_NORTHD
+AT_CLEANUP
+])
diff --git a/tests/system-ovn.at b/tests/system-ovn.at
index 8af7cb058..02bcb4c13 100644
--- a/tests/system-ovn.at
+++ b/tests/system-ovn.at
@@ -18680,3 +18680,248 @@ OVS_TRAFFIC_VSWITCHD_STOP(["/.*error receiving.*/d
 /.*terminating with signal 15.*/d"])
 AT_CLEANUP
 ])
+
+OVN_FOR_EACH_NORTHD([
+AT_SETUP([Distributed Load Balancer: IPv4 case])
+AT_KEYWORDS([ovnlb])
+
+# Simple Test for Basic Functionality Verification:
+# client - br-ext - br-int - outside-switch - (DGP) lr - backend
+# test case:
+# 1. Create centralized load balancer (ipv4), specifying gateway chassis for 
router.
+# 2. Moving gateway to non-existent chassis.
+# 3. Enable distributed option on load balancer.
+# 4. The distributed load balancer is expected to continue working.
+
+CHECK_CONNTRACK()
+CHECK_CONNTRACK_NAT()
+
+ovn_start
+OVS_TRAFFIC_VSWITCHD_START()
+ADD_BR([br-int])
+ADD_BR([br-ext])
+
+check ovs-ofctl add-flow br-ext action=normal
+# Set external-ids in br-int needed for ovn-controller
+check ovs-vsctl \
+        -- set Open_vSwitch . external-ids:system-id=hv1 \
+        -- set Open_vSwitch . 
external-ids:ovn-remote=unix:$ovs_base/ovn-sb/ovn-sb.sock \
+        -- set Open_vSwitch . external-ids:ovn-encap-type=geneve \
+        -- set Open_vSwitch . external-ids:ovn-encap-ip=169.0.0.1 \
+        -- set bridge br-int fail-mode=secure 
other-config:disable-in-band=true \
+        -- set Open_vSwitch . external-ids:ovn-bridge-mappings=phynet:br-ext
+
+# Start ovn-controller
+start_daemon ovn-controller
+
+check ovn-nbctl lr-add lr
+check ovn-nbctl ls-add internal
+check ovn-nbctl ls-add public
+
+check ovn-nbctl lrp-add lr lr-pub 00:00:01:01:02:03 192.168.100.1/24
+check ovn-nbctl lsp-add public pub-lr -- set Logical_Switch_Port pub-lr \
+    type=router options:router-port=lr-pub addresses=\"00:00:01:01:02:03\"
+
+check ovn-nbctl lrp-add lr lr-internal 00:00:01:01:02:04 192.168.200.1/24
+check ovn-nbctl lsp-add internal internal-lr -- set Logical_Switch_Port 
internal-lr \
+    type=router options:router-port=lr-internal addresses=\"00:00:01:01:02:04\"
+
+check ovn-nbctl lsp-add internal server_ipv4 -- lsp-set-addresses server_ipv4 
"unknown"
+
+check ovn-nbctl lsp-add public ln_port \
+                -- lsp-set-addresses ln_port unknown \
+                -- lsp-set-type ln_port localnet \
+                -- lsp-set-options ln_port network_name=phynet
+
+check ovn-nbctl lrp-set-gateway-chassis lr-pub hv1
+
+check ovn-nbctl lb-add lb1_ipv4 1.1.1.1:80 192.168.200.10:10880
+check ovn-nbctl lr-lb-add lr lb1_ipv4
+
+check ovn-nbctl --wait=hv sync
+
+ADD_NAMESPACES(client_ipv4)
+ADD_VETH(client_ipv4, client_ipv4, br-ext, "192.168.100.10/24", 
"f0:00:00:01:02:03", \
+         "192.168.100.1")
+
+ADD_NAMESPACES(server_ipv4)
+ADD_VETH(server_ipv4, server_ipv4, br-int, "192.168.200.10/24", 
"f0:00:0f:01:02:03", \
+         "192.168.200.1")
+
+NETNS_DAEMONIZE([server_ipv4], [nc -l -k 192.168.200.10 10880], [serverv4.pid])
+
+# Checking backend availability.
+NS_CHECK_EXEC([client_ipv4], [nc 1.1.1.1 80 -z], [0], [ignore], [ignore])
+
+# Changing the gateway to a non-existent one.
+check ovn-nbctl clear logical_router_port lr-pub gateway_chassis
+check ovn-nbctl lrp-set-gateway-chassis lr-pub hv2
+
+# ovn-controller currently does not recalculate local datapaths
+# when 'ha_chassis_group' change, so we reboot it.
+OVS_APP_EXIT_AND_WAIT([ovn-controller])
+start_daemon ovn-controller
+wait_for_ports_up
+
+# Check public switch not in local datapaths
+AT_CHECK([ovn-appctl -t ovn-controller debug/dump-local-datapaths], [0], [dnl
+Local datapaths:
+Datapath: lr, type: router
+Datapath: internal, type: switch
+])
+
+AT_CHECK([ovs-ofctl dump-groups br-int | sed -e 
's/table=[[0-9]]*/table=<cleared>/'], [0], [dnl
+NXST_GROUP_DESC reply (xid=0x2):
+])
+
+check ovn-nbctl set load_balancer lb1_ipv4 options:distributed=true
+check ovn-nbctl set Load_Balancer lb1_ipv4 
ip_port_mappings:192.168.200.10=server_ipv4
+check ovn-nbctl --wait=hv sync
+
+# Check that external switch has been added to local datapaths on distrubuted 
nodes
+# when 'distributed' option is enabled on load balancer.
+AT_CHECK([ovn-appctl -t ovn-controller debug/dump-local-datapaths], [0], [dnl
+Local datapaths:
+Datapath: lr, type: router
+Datapath: internal, type: switch
+Datapath: public, type: switch
+])
+
+AT_CHECK([ovs-ofctl dump-groups br-int | sed -e 
's/table=[[0-9]]*/table=<cleared>/'], [0], [dnl
+NXST_GROUP_DESC reply (xid=0x2):
+ 
group_id=1,type=select,selection_method=dp_hash,bucket=bucket_id:0,weight:100,actions=ct(commit,table=<cleared>,zone=NXM_NX_REG11[[0..15]],nat(dst=192.168.200.10:10880),exec(load:0x1->NXM_NX_CT_MARK[[1]]))
+])
+
+# Checking backend availability.
+NS_CHECK_EXEC([client_ipv4], [nc 1.1.1.1 80 -z], [0], [ignore], [ignore])
+
+check ovn-nbctl lb-del lb1_ipv4
+
+OVS_TRAFFIC_VSWITCHD_STOP(["/failed to query port patch-.*/d
+/connection dropped.*/d"])
+AT_CLEANUP
+])
+
+OVN_FOR_EACH_NORTHD([
+AT_SETUP([Distributed Load Balancer: IPv6 case])
+AT_KEYWORDS([ovnlb])
+
+# Simple Test for Basic Functionality Verification:
+# client - br-ext - br-int - outside-switch - (DGP) lr - backend
+# test case:
+# 1. Create centralized load balancer (ipv6), specifying gateway chassis for 
router.
+# 2. Moving gateway to non-existent chassis.
+# 3. Enable distributed option on load balancer.
+# 4. The distributed load balancer is expected to continue working.
+
+CHECK_CONNTRACK()
+CHECK_CONNTRACK_NAT()
+
+ovn_start
+OVS_TRAFFIC_VSWITCHD_START()
+ADD_BR([br-int])
+ADD_BR([br-ext])
+
+check ovs-ofctl add-flow br-ext action=normal
+# Set external-ids in br-int needed for ovn-controller
+check ovs-vsctl \
+        -- set Open_vSwitch . external-ids:system-id=hv1 \
+        -- set Open_vSwitch . 
external-ids:ovn-remote=unix:$ovs_base/ovn-sb/ovn-sb.sock \
+        -- set Open_vSwitch . external-ids:ovn-encap-type=geneve \
+        -- set Open_vSwitch . external-ids:ovn-encap-ip=169.0.0.1 \
+        -- set bridge br-int fail-mode=secure 
other-config:disable-in-band=true \
+        -- set Open_vSwitch . external-ids:ovn-bridge-mappings=phynet:br-ext
+
+# Start ovn-controller
+start_daemon ovn-controller
+
+check ovn-nbctl lr-add lr
+check ovn-nbctl ls-add internal
+check ovn-nbctl ls-add public
+
+check ovn-nbctl lrp-add lr lr-pub 00:00:01:01:02:03 2001:db8:abcd:0002::bad/64
+check ovn-nbctl lsp-add public pub-lr -- set Logical_Switch_Port pub-lr \
+    type=router options:router-port=lr-pub addresses=\"00:00:01:01:02:03\"
+
+check ovn-nbctl lrp-add lr lr-internal 00:00:01:01:02:04 
2001:db8:abcd:0001::c0fe/64
+check ovn-nbctl lsp-add internal internal-lr -- set Logical_Switch_Port 
internal-lr \
+    type=router options:router-port=lr-internal addresses=\"00:00:01:01:02:04\"
+
+check ovn-nbctl lsp-add internal server_ipv6 -- lsp-set-addresses server_ipv6 
"unknown"
+
+check ovn-nbctl lsp-add public ln_port \
+                -- lsp-set-addresses ln_port unknown \
+                -- lsp-set-type ln_port localnet \
+                -- lsp-set-options ln_port network_name=phynet
+
+check ovn-nbctl lrp-set-gateway-chassis lr-pub hv1
+
+check ovn-nbctl lb-add lb1_ipv6 [[2000::1]]:80  [[2001:db8:abcd:1::2]]:10882
+check ovn-nbctl lr-lb-add lr lb1_ipv6
+
+check ovn-nbctl --wait=hv sync
+
+ADD_NAMESPACES(client_ipv6)
+ADD_VETH(client_ipv6, client_ipv6, br-ext, "2001:db8:abcd:2::f00d/64", 
"f0:00:00:01:02:06", \
+         "2001:db8:abcd:0002::bad")
+
+ADD_NAMESPACES(server_ipv6)
+ADD_VETH(server_ipv6, server_ipv6, br-int, "2001:db8:abcd:1::2/64", 
"f0:00:0f:01:02:04", \
+         "2001:db8:abcd:1::c0fe")
+
+# Wait for IPv6 address to be ready
+sleep 5
+
+NETNS_DAEMONIZE([server_ipv6], [ncat -6 -l -k 2001:db8:abcd:1::2 10882], 
[serverv6.pid])
+
+# Checking backend availability.
+NS_CHECK_EXEC([client_ipv6], [nc -6 2000::1 80 -z], [0], [ignore], [ignore])
+
+# Changing the gateway to a non-existent one.
+check ovn-nbctl clear logical_router_port lr-pub gateway_chassis
+check ovn-nbctl lrp-set-gateway-chassis lr-pub hv2
+
+# ovn-controller currently does not recalculate local datapaths
+# when 'ha_chassis_group' change, so we reboot it.
+OVS_APP_EXIT_AND_WAIT([ovn-controller])
+start_daemon ovn-controller
+wait_for_ports_up
+
+# Check public switch not in local datapaths
+AT_CHECK([ovn-appctl -t ovn-controller debug/dump-local-datapaths], [0], [dnl
+Local datapaths:
+Datapath: lr, type: router
+Datapath: internal, type: switch
+])
+
+AT_CHECK([ovs-ofctl dump-groups br-int | sed -e 
's/table=[[0-9]]*/table=<cleared>/'], [0], [dnl
+NXST_GROUP_DESC reply (xid=0x2):
+])
+
+check ovn-nbctl set load_balancer lb1_ipv6 options:distributed=true
+check ovn-nbctl set Load_Balancer lb1_ipv6 
ip_port_mappings:\"[[2001:db8:abcd:1::2]]\"=\"server_ipv6\"
+check ovn-nbctl --wait=hv sync
+
+# Check that external switch has been added to local datapaths on distrubuted 
nodes
+# when 'distributed' option is enabled on load balancer.
+AT_CHECK([ovn-appctl -t ovn-controller debug/dump-local-datapaths], [0], [dnl
+Local datapaths:
+Datapath: lr, type: router
+Datapath: internal, type: switch
+Datapath: public, type: switch
+])
+
+AT_CHECK([ovs-ofctl dump-groups br-int | sed -e 
's/table=[[0-9]]*/table=<cleared>/'], [0], [dnl
+NXST_GROUP_DESC reply (xid=0x2):
+ 
group_id=1,type=select,selection_method=dp_hash,bucket=bucket_id:0,weight:100,actions=ct(commit,table=<cleared>,zone=NXM_NX_REG11[[0..15]],nat(dst=[[2001:db8:abcd:1::2]]:10882),exec(load:0x1->NXM_NX_CT_MARK[[1]]))
+])
+
+# Checking backend availability.
+NS_CHECK_EXEC([client_ipv6], [nc -6 2000::1 80 -z], [0], [ignore], [ignore])
+
+check ovn-nbctl lb-del lb1_ipv6
+
+OVS_TRAFFIC_VSWITCHD_STOP(["/failed to query port patch-.*/d
+/connection dropped.*/d"])
+AT_CLEANUP
+])
-- 
2.48.1

_______________________________________________
dev mailing list
[email protected]
https://mail.openvswitch.org/mailman/listinfo/ovs-dev

Reply via email to