Set specific keepalive options by default on supported platforms

distribution/docker/src/test/resources/rest-api-spec/test/20_settings.yml

@@ -0,0 +1,9 @@
+---
+"Default TCP keepalive settings":
+  - do:
+      cluster.get_settings:
+        include_defaults: true
+
+  - match: { defaults.network.tcp.keep_idle: "60" }
+  - match: { defaults.network.tcp.keep_interval: "10" }
+  - match: { defaults.network.tcp.keep_count: "3" }

docs/reference/modules/transport.asciidoc

@@ -88,19 +88,22 @@ example above:
    determines the time in seconds that a connection must be idle before
    starting to send TCP keepalive probes.
    Only applicable on Linux and Mac, and requires JDK 11 or newer.
-   Defaults to -1, which does not set this option at the socket level, but
-   uses default system configuration instead.
+   Defaults to 60 on applicable configurations, and -1 otherwise, which does
+   not set this option at the socket level, but uses the default system
+   configuration instead.
 * `tcp.keep_interval`: Configures the `TCP_KEEPINTVL` option for this socket,
    which determines the time in seconds between sending TCP keepalive probes.
    Only applicable on Linux and Mac, and requires JDK 11 or newer.
-   Defaults to -1, which does not set this option at the socket level, but
-   uses default system configuration instead.
+   Defaults to 10 on applicable configurations, and -1 otherwise, which does
+   not set this option at the socket level, but uses the default system
+   configuration instead.
 * `tcp.keep_count`: Configures the `TCP_KEEPCNT` option for this socket, which
    determines the number of unacknowledged TCP keepalive probes that may be
    sent on a connection before it is dropped.
    Only applicable on Linux and Mac, and requires JDK 11 or newer.
-   Defaults to -1, which does not set this option at the socket level, but
-   uses default system configuration instead.
+   Defaults to 3 on applicable configurations, and -1 otherwise, which does
+   not set this option at the socket level, but uses the default system
+   configuration instead.
 * `tcp.reuse_address`: Configures the `SO_REUSEADDR` option for this socket
 * `tcp.send_buffer_size`: Configures the send buffer size of the socket
 * `tcp.receive_buffer_size`: Configures the receive buffer size of the socket

modules/transport-netty4/src/main/java/org/elasticsearch/transport/netty4/Netty4Transport.java

@@ -149,25 +149,23 @@ private Bootstrap createClientBootstrap(SharedGroupFactory.SharedGroup sharedGro
         bootstrap.option(ChannelOption.TCP_NODELAY, TransportSettings.TCP_NO_DELAY.get(settings));
         bootstrap.option(ChannelOption.SO_KEEPALIVE, TransportSettings.TCP_KEEP_ALIVE.get(settings));
         if (TransportSettings.TCP_KEEP_ALIVE.get(settings)) {
-            // Netty logs a warning if it can't set the option, so try this only on supported platforms
-            if (IOUtils.LINUX || IOUtils.MAC_OS_X) {
-                if (TransportSettings.TCP_KEEP_IDLE.get(settings) >= 0) {
-                    final SocketOption<Integer> keepIdleOption = NetUtils.getTcpKeepIdleSocketOptionOrNull();
-                    if (keepIdleOption != null) {
-                        bootstrap.option(NioChannelOption.of(keepIdleOption), TransportSettings.TCP_KEEP_IDLE.get(settings));
-                    }
+            // Note that Netty logs a warning if it can't set the option
+            if (TransportSettings.TCP_KEEP_IDLE.get(settings) >= 0) {
+                final SocketOption<Integer> keepIdleOption = NetUtils.getTcpKeepIdleSocketOptionOrNull();
+                if (keepIdleOption != null) {
+                    bootstrap.option(NioChannelOption.of(keepIdleOption), TransportSettings.TCP_KEEP_IDLE.get(settings));
                 }
-                if (TransportSettings.TCP_KEEP_INTERVAL.get(settings) >= 0) {
-                    final SocketOption<Integer> keepIntervalOption = NetUtils.getTcpKeepIntervalSocketOptionOrNull();
-                    if (keepIntervalOption != null) {
-                        bootstrap.option(NioChannelOption.of(keepIntervalOption), TransportSettings.TCP_KEEP_INTERVAL.get(settings));
-                    }
+            }
+            if (TransportSettings.TCP_KEEP_INTERVAL.get(settings) >= 0) {
+                final SocketOption<Integer> keepIntervalOption = NetUtils.getTcpKeepIntervalSocketOptionOrNull();
+                if (keepIntervalOption != null) {
+                    bootstrap.option(NioChannelOption.of(keepIntervalOption), TransportSettings.TCP_KEEP_INTERVAL.get(settings));
                 }
-                if (TransportSettings.TCP_KEEP_COUNT.get(settings) >= 0) {
-                    final SocketOption<Integer> keepCountOption = NetUtils.getTcpKeepCountSocketOptionOrNull();
-                    if (keepCountOption != null) {
-                        bootstrap.option(NioChannelOption.of(keepCountOption), TransportSettings.TCP_KEEP_COUNT.get(settings));
-                    }
+            }
+            if (TransportSettings.TCP_KEEP_COUNT.get(settings) >= 0) {
+                final SocketOption<Integer> keepCountOption = NetUtils.getTcpKeepCountSocketOptionOrNull();
+                if (keepCountOption != null) {
+                    bootstrap.option(NioChannelOption.of(keepCountOption), TransportSettings.TCP_KEEP_COUNT.get(settings));
                 }
             }
         }

server/src/main/java/org/elasticsearch/common/network/NetworkService.java

@@ -19,9 +19,12 @@
 
 package org.elasticsearch.common.network;
 
+import org.elasticsearch.bootstrap.JavaVersion;
+import org.elasticsearch.common.Booleans;
 import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.unit.ByteSizeValue;
+import org.elasticsearch.core.internal.io.IOUtils;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -50,12 +53,16 @@ public final class NetworkService {
         Setting.boolSetting("network.tcp.no_delay", true, Property.NodeScope);
     public static final Setting<Boolean> TCP_KEEP_ALIVE =
         Setting.boolSetting("network.tcp.keep_alive", true, Property.NodeScope);
+    public static final boolean SET_EXTRA_KEEP_ALIVE_OPTIONS =
+        Booleans.parseBoolean(System.getProperty("es.network.tcp.extra_keep_alive_options", "false")) == false &&
+            (IOUtils.LINUX || IOUtils.MAC_OS_X) &&
+            JavaVersion.current().compareTo(JavaVersion.parse("11")) >= 0;
     public static final Setting<Integer> TCP_KEEP_IDLE =
-        Setting.intSetting("network.tcp.keep_idle", -1, -1, Property.NodeScope);
+        Setting.intSetting("network.tcp.keep_idle", SET_EXTRA_KEEP_ALIVE_OPTIONS ? 60 : -1, -1, Property.NodeScope);
     public static final Setting<Integer> TCP_KEEP_INTERVAL =
-        Setting.intSetting("network.tcp.keep_interval", -1, -1, Property.NodeScope);
+        Setting.intSetting("network.tcp.keep_interval", SET_EXTRA_KEEP_ALIVE_OPTIONS ? 10 : -1, -1, Property.NodeScope);
     public static final Setting<Integer> TCP_KEEP_COUNT =
-        Setting.intSetting("network.tcp.keep_count", -1, -1, Property.NodeScope);
+        Setting.intSetting("network.tcp.keep_count", SET_EXTRA_KEEP_ALIVE_OPTIONS ? 3 : -1, -1, Property.NodeScope);
     public static final Setting<Boolean> TCP_REUSE_ADDRESS =
         Setting.boolSetting("network.tcp.reuse_address", NetworkUtils.defaultReuseAddress(), Property.NodeScope);
     public static final Setting<ByteSizeValue> TCP_SEND_BUFFER_SIZE =