load balancer: Add a option to configure the table size of maglev (#12870)

Currently, the maglev hash algorithm default to table size to 65537.
It is the recommended size by a paper but it is better if the user
can set this value.

This patch introduces a new MaglevLbConfig that contains table
size of maglev.

So, now, the user can set the table size of maglev by their situation.

Signed-off-by: DongRyeol Cha <dr83.cha@samsung.com>

Mirrored from https://github.com/envoyproxy/envoy @ 5fd73ca889aa12618c626c96bb33fde4707f8bf0

envoy/config/cluster/v3/cluster.proto

@@ -43,7 +43,7 @@ message ClusterCollection {
 }
 
 // Configuration for a single upstream cluster.
-// [#next-free-field: 52]
+// [#next-free-field: 53]
 message Cluster {
   option (udpa.annotations.versioning).previous_message_type = "envoy.api.v2.Cluster";
 
@@ -410,6 +410,16 @@ message Cluster {
     google.protobuf.UInt64Value maximum_ring_size = 4 [(validate.rules).uint64 = {lte: 8388608}];
   }
 
+  // Specific configuration for the :ref:`Maglev<arch_overview_load_balancing_types_maglev>`
+  // load balancing policy.
+  message MaglevLbConfig {
+    // The table size for Maglev hashing. The Maglev aims for ‘minimal disruption’ rather than an absolute guarantee.
+    // Minimal disruption means that when the set of upstreams changes, a connection will likely be sent to the same
+    // upstream as it was before. Increasing the table size reduces the amount of disruption.
+    // The table size must be prime number. If it is not specified, the default is 65537.
+    google.protobuf.UInt64Value table_size = 1;
+  }
+
   // Specific configuration for the
   // :ref:`Original Destination <arch_overview_load_balancing_types_original_destination>`
   // load balancing policy.
@@ -830,15 +840,19 @@ message Cluster {
 
   // Optional configuration for the load balancing algorithm selected by
   // LbPolicy. Currently only
-  // :ref:`RING_HASH<envoy_api_enum_value_config.cluster.v3.Cluster.LbPolicy.RING_HASH>` and
+  // :ref:`RING_HASH<envoy_api_enum_value_config.cluster.v3.Cluster.LbPolicy.RING_HASH>`,
+  // :ref:`MAGLEV<envoy_api_enum_value_config.cluster.v3.Cluster.LbPolicy.MAGLEV>` and
   // :ref:`LEAST_REQUEST<envoy_api_enum_value_config.cluster.v3.Cluster.LbPolicy.LEAST_REQUEST>`
   // has additional configuration options.
-  // Specifying ring_hash_lb_config or least_request_lb_config without setting the corresponding
+  // Specifying ring_hash_lb_config or maglev_lb_config or least_request_lb_config without setting the corresponding
   // LbPolicy will generate an error at runtime.
   oneof lb_config {
     // Optional configuration for the Ring Hash load balancing policy.
     RingHashLbConfig ring_hash_lb_config = 23;
 
+    // Optional configuration for the Maglev load balancing policy.
+    MaglevLbConfig maglev_lb_config = 52;
+
     // Optional configuration for the Original Destination load balancing policy.
     OriginalDstLbConfig original_dst_lb_config = 34;
 

envoy/config/cluster/v4alpha/cluster.proto

@@ -45,7 +45,7 @@ message ClusterCollection {
 }
 
 // Configuration for a single upstream cluster.
-// [#next-free-field: 52]
+// [#next-free-field: 53]
 message Cluster {
   option (udpa.annotations.versioning).previous_message_type = "envoy.config.cluster.v3.Cluster";
 
@@ -413,6 +413,19 @@ message Cluster {
     google.protobuf.UInt64Value maximum_ring_size = 4 [(validate.rules).uint64 = {lte: 8388608}];
   }
 
+  // Specific configuration for the :ref:`Maglev<arch_overview_load_balancing_types_maglev>`
+  // load balancing policy.
+  message MaglevLbConfig {
+    option (udpa.annotations.versioning).previous_message_type =
+        "envoy.config.cluster.v3.Cluster.MaglevLbConfig";
+
+    // The table size for Maglev hashing. The Maglev aims for ‘minimal disruption’ rather than an absolute guarantee.
+    // Minimal disruption means that when the set of upstreams changes, a connection will likely be sent to the same
+    // upstream as it was before. Increasing the table size reduces the amount of disruption.
+    // The table size must be prime number. If it is not specified, the default is 65537.
+    google.protobuf.UInt64Value table_size = 1;
+  }
+
   // Specific configuration for the
   // :ref:`Original Destination <arch_overview_load_balancing_types_original_destination>`
   // load balancing policy.
@@ -837,15 +850,19 @@ message Cluster {
 
   // Optional configuration for the load balancing algorithm selected by
   // LbPolicy. Currently only
-  // :ref:`RING_HASH<envoy_api_enum_value_config.cluster.v4alpha.Cluster.LbPolicy.RING_HASH>` and
+  // :ref:`RING_HASH<envoy_api_enum_value_config.cluster.v4alpha.Cluster.LbPolicy.RING_HASH>`,
+  // :ref:`MAGLEV<envoy_api_enum_value_config.cluster.v4alpha.Cluster.LbPolicy.MAGLEV>` and
   // :ref:`LEAST_REQUEST<envoy_api_enum_value_config.cluster.v4alpha.Cluster.LbPolicy.LEAST_REQUEST>`
   // has additional configuration options.
-  // Specifying ring_hash_lb_config or least_request_lb_config without setting the corresponding
+  // Specifying ring_hash_lb_config or maglev_lb_config or least_request_lb_config without setting the corresponding
   // LbPolicy will generate an error at runtime.
   oneof lb_config {
     // Optional configuration for the Ring Hash load balancing policy.
     RingHashLbConfig ring_hash_lb_config = 23;
 
+    // Optional configuration for the Maglev load balancing policy.
+    MaglevLbConfig maglev_lb_config = 52;
+
     // Optional configuration for the Original Destination load balancing policy.
     OriginalDstLbConfig original_dst_lb_config = 34;