Expose configuration of memberlist packet compression. (#4346)

* Expose configuration of memberlist packet compression.

Allows manually specifying whether memberlist should compress packets
via a new configuration flag: `-memberlist.enable-compression`.

This typically has little benefit for Cortex, as the ring state messages
are already compressed with Snappy, the second layer of compression does
not achieve any additional saving. It's not clear cut whether there
might still be some benefit for internal memberlist messages; this needs
to be evaluated in a environment of some reasonable scale.

Signed-off-by: Steve Simpson <[email protected]>

* Review comments.

Signed-off-by: Steve Simpson <[email protected]>

* Review comments.

Signed-off-by: Steve Simpson <[email protected]>

Author: stevesg

CHANGELOG.md

@@ -22,6 +22,7 @@
   * `-compactor.ring.heartbeat-period`
   * `-store-gateway.sharding-ring.heartbeat-period`
 * [ENHANCEMENT] Memberlist: optimized receive path for processing ring state updates, to help reduce CPU utilization in large clusters. #4345
+* [ENHANCEMENT] Memberlist: expose configuration of memberlist packet compression via `-memberlist.compression=enabled`. #4346
 * [BUGFIX] HA Tracker: when cleaning up obsolete elected replicas from KV store, tracker didn't update number of cluster per user correctly. #4336
 
 ## 1.10.0-rc.0 / 2021-06-28

docs/configuration/config-file-reference.md

@@ -3796,6 +3796,11 @@ The `memberlist_config` configures the Gossip memberlist.
 # CLI flag: -memberlist.dead-node-reclaim-time
 [dead_node_reclaim_time: <duration> | default = 0s]
 
+# Enable message compression. This can be used to reduce bandwidth usage at the
+# cost of slightly more CPU utilization.
+# CLI flag: -memberlist.compression-enabled
+[compression_enabled: <boolean> | default = true]
+
 # Other cluster members to join. Can be specified multiple times. It can be an
 # IP, hostname or an entry specified in the DNS Service Discovery format (see
 # https://cortexmetrics.io/docs/configuration/arguments/#dns-service-discovery

integration/integration_memberlist_single_binary_test.go

@@ -23,15 +23,21 @@ import (
 
 func TestSingleBinaryWithMemberlist(t *testing.T) {
 	t.Run("default", func(t *testing.T) {
-		testSingleBinaryEnv(t, false)
+		testSingleBinaryEnv(t, false, nil)
 	})
 
 	t.Run("tls", func(t *testing.T) {
-		testSingleBinaryEnv(t, true)
+		testSingleBinaryEnv(t, true, nil)
+	})
+
+	t.Run("compression-disabled", func(t *testing.T) {
+		testSingleBinaryEnv(t, false, map[string]string{
+			"-memberlist.compression-enabled": "false",
+		})
 	})
 }
 
-func testSingleBinaryEnv(t *testing.T, tlsEnabled bool) {
+func testSingleBinaryEnv(t *testing.T, tlsEnabled bool, flags map[string]string) {
 	s, err := e2e.NewScenario(networkName)
 	require.NoError(t, err)
 	defer s.Close()
@@ -65,13 +71,13 @@ func testSingleBinaryEnv(t *testing.T, tlsEnabled bool) {
 			filepath.Join(s.SharedDir(), clientKeyFile),
 		))
 
-		cortex1 = newSingleBinary("cortex-1", memberlistDNS, "")
-		cortex2 = newSingleBinary("cortex-2", memberlistDNS, networkName+"-cortex-1:8000")
-		cortex3 = newSingleBinary("cortex-3", memberlistDNS, networkName+"-cortex-1:8000")
+		cortex1 = newSingleBinary("cortex-1", memberlistDNS, "", flags)
+		cortex2 = newSingleBinary("cortex-2", memberlistDNS, networkName+"-cortex-1:8000", flags)
+		cortex3 = newSingleBinary("cortex-3", memberlistDNS, networkName+"-cortex-1:8000", flags)
 	} else {
-		cortex1 = newSingleBinary("cortex-1", "", "")
-		cortex2 = newSingleBinary("cortex-2", "", networkName+"-cortex-1:8000")
-		cortex3 = newSingleBinary("cortex-3", "", networkName+"-cortex-1:8000")
+		cortex1 = newSingleBinary("cortex-1", "", "", flags)
+		cortex2 = newSingleBinary("cortex-2", "", networkName+"-cortex-1:8000", flags)
+		cortex3 = newSingleBinary("cortex-3", "", networkName+"-cortex-1:8000", flags)
 	}
 
 	// start cortex-1 first, as cortex-2 and cortex-3 both connect to cortex-1
@@ -109,7 +115,7 @@ func testSingleBinaryEnv(t *testing.T, tlsEnabled bool) {
 	require.NoError(t, s.Stop(cortex3))
 }
 
-func newSingleBinary(name string, servername string, join string) *e2ecortex.CortexService {
+func newSingleBinary(name string, servername string, join string, testFlags map[string]string) *e2ecortex.CortexService {
 	flags := map[string]string{
 		"-ingester.final-sleep":              "0s",
 		"-ingester.join-after":               "0s", // join quickly
@@ -132,6 +138,7 @@ func newSingleBinary(name string, servername string, join string) *e2ecortex.Cor
 		mergeFlags(
 			ChunksStorageFlags(),
 			flags,
+			testFlags,
 			getTLSFlagsWithPrefix("memberlist", servername, servername == ""),
 		),
 		"",
@@ -170,7 +177,7 @@ func TestSingleBinaryWithMemberlistScaling(t *testing.T) {
 		if i > 0 {
 			join = e2e.NetworkContainerHostPort(networkName, "cortex-1", 8000)
 		}
-		c := newSingleBinary(name, "", join)
+		c := newSingleBinary(name, "", join, nil)
 		require.NoError(t, s.StartAndWaitReady(c))
 		instances = append(instances, c)
 	}

pkg/ring/kv/memberlist/memberlist_client.go

@@ -136,6 +136,7 @@ type KVConfig struct {
 	GossipNodes         int           `yaml:"gossip_nodes"`
 	GossipToTheDeadTime time.Duration `yaml:"gossip_to_dead_nodes_time"`
 	DeadNodeReclaimTime time.Duration `yaml:"dead_node_reclaim_time"`
+	EnableCompression   bool          `yaml:"compression_enabled"`
 
 	// List of members to join
 	JoinMembers      flagext.StringSlice `yaml:"join_members"`
@@ -187,6 +188,7 @@ func (cfg *KVConfig) RegisterFlagsWithPrefix(f *flag.FlagSet, prefix string) {
 	f.DurationVar(&cfg.GossipToTheDeadTime, prefix+"memberlist.gossip-to-dead-nodes-time", mlDefaults.GossipToTheDeadTime, "How long to keep gossiping to dead nodes, to give them chance to refute their death.")
 	f.DurationVar(&cfg.DeadNodeReclaimTime, prefix+"memberlist.dead-node-reclaim-time", mlDefaults.DeadNodeReclaimTime, "How soon can dead node's name be reclaimed with new address. 0 to disable.")
 	f.IntVar(&cfg.MessageHistoryBufferBytes, prefix+"memberlist.message-history-buffer-bytes", 0, "How much space to use for keeping received and sent messages in memory for troubleshooting (two buffers). 0 to disable.")
+	f.BoolVar(&cfg.EnableCompression, prefix+"memberlist.compression-enabled", mlDefaults.EnableCompression, "Enable message compression. This can be used to reduce bandwidth usage at the cost of slightly more CPU utilization.")
 
 	cfg.TCPTransport.RegisterFlags(f, prefix)
 }
@@ -380,6 +382,7 @@ func (m *KV) buildMemberlistConfig() (*memberlist.Config, error) {
 	mlCfg.GossipNodes = m.cfg.GossipNodes
 	mlCfg.GossipToTheDeadTime = m.cfg.GossipToTheDeadTime
 	mlCfg.DeadNodeReclaimTime = m.cfg.DeadNodeReclaimTime
+	mlCfg.EnableCompression = m.cfg.EnableCompression
 
 	if m.cfg.NodeName != "" {
 		mlCfg.Name = m.cfg.NodeName