change gossip dns conn limit by ENV

nodeup/pkg/bootstrap/install.go

@@ -119,6 +119,12 @@ func (i *Installation) buildSystemdJob() *nodetasks.Service {
 		buffer.WriteString("\" ")
 	}
 
+	if os.Getenv("GOSSIP_DNS_CONN_LIMIT") != "" {
+		buffer.WriteString("\"GOSSIP_DNS_CONN_LIMIT=")
+		buffer.WriteString(os.Getenv("GOSSIP_DNS_CONN_LIMIT"))
+		buffer.WriteString("\" ")
+	}
+
 	// Pass in required credentials when using user-defined s3 endpoint
 	if os.Getenv("S3_ENDPOINT") != "" {
 		buffer.WriteString("\"S3_ENDPOINT=")

nodeup/pkg/model/protokube.go

@@ -361,6 +361,15 @@ func (t *ProtokubeBuilder) ProtokubeEnvironmentVariables() string {
 
 	// TODO write out an environments file for this.  This is getting a tad long.
 
+	// Passin gossip dns connection limit
+	if os.Getenv("GOSSIP_DNS_CONN_LIMIT") != "" {
+		buffer.WriteString(" ")
+		buffer.WriteString("-e 'GOSSIP_DNS_CONN_LIMIT=")
+		buffer.WriteString(os.Getenv("GOSSIP_DNS_CONN_LIMIT"))
+		buffer.WriteString("'")
+		buffer.WriteString(" ")
+	}
+
 	// Pass in required credentials when using user-defined s3 endpoint
 	if os.Getenv("AWS_REGION") != "" {
 		buffer.WriteString(" ")

pkg/model/bootstrapscript.go

@@ -60,6 +60,11 @@ func (b *BootstrapScript) KubeEnv(ig *kops.InstanceGroup) (string, error) {
 
 func (b *BootstrapScript) buildEnvironmentVariables(cluster *kops.Cluster) (map[string]string, error) {
 	env := make(map[string]string)
+
+	if os.Getenv("GOSSIP_DNS_CONN_LIMIT") != "" {
+		env["GOSSIP_DNS_CONN_LIMIT"] = os.Getenv("GOSSIP_DNS_CONN_LIMIT")
+	}
+
 	if os.Getenv("S3_ENDPOINT") != "" {
 		env["S3_ENDPOINT"] = os.Getenv("S3_ENDPOINT")
 		env["S3_REGION"] = os.Getenv("S3_REGION")

protokube/pkg/gossip/mesh/gossip.go

@@ -19,6 +19,7 @@ package mesh
 import (
 	"fmt"
 	"net"
+	"os"
 	"strconv"
 	"time"
 
@@ -39,10 +40,23 @@ type MeshGossiper struct {
 }
 
 func NewMeshGossiper(listen string, channelName string, nodeName string, password []byte, seeds gossip.SeedProvider) (*MeshGossiper, error) {
+
+	connLimit := 64
+	gossipDnsConnLimit := os.Getenv("GOSSIP_DNS_CONN_LIMIT")
+	if gossipDnsConnLimit != "" {
+		limit, err := strconv.Atoi(gossipDnsConnLimit)
+		if err != nil {
+			return nil, fmt.Errorf("cannot parse env GOSSIP_DNS_CONN_LIMIT value: %v", gossipDnsConnLimit)
+		}
+		connLimit = limit
+	}
+
+	glog.Infof("gossip dns connection limit is:%d", connLimit)
+
 	meshConfig := mesh.Config{
 		ProtocolMinVersion: mesh.ProtocolMinVersion,
 		Password:           password,
-		ConnLimit:          64,
+		ConnLimit:          connLimit,
 		PeerDiscovery:      true,
 		//TrustedSubnets:     []*net.IPNet{},
 	}