diff mbox series

[ovs-dev,RFC,ovn,v2] ovn-northd: Support optionally avoid static neighbor flows in routers.

Message ID 1589614395-99499-1-git-send-email-hzhou@ovn.org
State New
Headers show
Series [ovs-dev,RFC,ovn,v2] ovn-northd: Support optionally avoid static neighbor flows in routers. | expand

Commit Message

Han Zhou May 16, 2020, 7:33 a.m. UTC
Support option:dynamic_neigh_routers for logical routers, so that in
particular use cases static neighbor flows are not prepopulated IP
addresses belonging to neighbor router ports, to avoid flow exploding
problem reported for ovn-kubernetes large scale setup.

Reported-by: Girish Moodalbail <gmoodalbail@gmail.com>
Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2020-May/049995.html
Signed-off-by: Han Zhou <hzhou@ovn.org>
---
v1 -> v2: Change the options to skip flows only for routers. In v1 it
          skipped other neighbor flows but not router neighbors which
          was not the purpose of this patch.

 northd/ovn-northd.8.xml |  5 ++++-
 northd/ovn-northd.c     |  6 ++++++
 ovn-nb.xml              | 13 +++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/northd/ovn-northd.8.xml b/northd/ovn-northd.8.xml
index 8f224b0..95a6051 100644
--- a/northd/ovn-northd.8.xml
+++ b/northd/ovn-northd.8.xml
@@ -2692,7 +2692,10 @@  outport = <var>P</var>;
           <code>Logical_Switch_Port</code> table.  For router ports
           connected to other logical routers, MAC bindings can be known
           statically from the <code>mac</code> and <code>networks</code>
-          column in the <code>Logical_Router_Port</code> table.
+          column in the <code>Logical_Router_Port</code> table.  (Note: the
+          flow is NOT installed for the IP addresses that belong to a neighbor
+          logical router port if the current router has the
+          <code>options:dynamic_neigh_routers</code> set to <code>true</code>)
         </p>
 
         <p>
diff --git a/northd/ovn-northd.c b/northd/ovn-northd.c
index 87625c3..e5858e2 100644
--- a/northd/ovn-northd.c
+++ b/northd/ovn-northd.c
@@ -9997,6 +9997,12 @@  build_lrouter_flows(struct hmap *datapaths, struct hmap *ports,
                 continue;
             }
 
+            if (peer->od->nbr &&
+                smap_get_bool(&peer->od->nbr->options,
+                              "dynamic_neigh_routers", false)) {
+                continue;
+            }
+
             for (size_t i = 0; i < op->od->n_router_ports; i++) {
                 const char *router_port_name = smap_get(
                                     &op->od->router_ports[i]->nbsp->options,
diff --git a/ovn-nb.xml b/ovn-nb.xml
index 95ee4c9..131a4de 100644
--- a/ovn-nb.xml
+++ b/ovn-nb.xml
@@ -1840,6 +1840,19 @@ 
           connected to the logical router. Default: False.
         </p>
       </column>
+      <column name="options" key="dynamic_neigh_routers" type='{"type": "boolean"}'>
+        <p>
+          If set to <code>true</code>, the router will resolve neighbor
+          routers' MAC addresses only by dynamic ARP/ND, instead of
+          prepopulating static mappings for all neighbor routers in the ARP/ND
+          Resolution stage.  This reduces number of flows, but requires ARP/ND
+          messages to resolve the IP-MAC bindings when needed.  It is
+          <code>false</code> by default.  It is recommended to set to
+          <code>true</code> when a large number of logical routers are
+          connected to the same logical switch but most of them never need to
+          send traffic between each other.
+        </p>
+      </column>
     </group>
 
     <group title="Common Columns">