diff --git a/.gitignore b/.gitignore
index ccdff0b8..c422e771 100644
--- a/.gitignore
+++ b/.gitignore
@@ -39,3 +39,4 @@ nbproject
 .sonar-ide.properties
 .clover
 *~
+.DS_Store
diff --git a/10/mysql-tomcat/Dockerfile b/10/mysql-tomcat/Dockerfile
index 9feee5d6..e02d6fb7 100644
--- a/10/mysql-tomcat/Dockerfile
+++ b/10/mysql-tomcat/Dockerfile
@@ -64,6 +64,9 @@ COPY tomcat/setenv.sh /usr/local/tomcat/bin/
 # Setup the XWiki Hibernate configuration
 COPY xwiki/hibernate.cfg.xml /usr/local/tomcat/webapps/ROOT/WEB-INF/hibernate.cfg.xml
 
+# Configure JGroups. 
+COPY jgroups/* /usr/local/tomcat/webapps/ROOT/WEB-INF/observation/remote/jgroups
+
 # Set a specific distribution id in XWiki for this docker packaging.
 RUN sed -i 's/<id>org.xwiki.platform:xwiki-platform-distribution-war/<id>org.xwiki.platform:xwiki-platform-distribution-docker/' \
   /usr/local/tomcat/webapps/ROOT/META-INF/extension.xed
diff --git a/10/mysql-tomcat/jgroups/udp.xml b/10/mysql-tomcat/jgroups/udp.xml
new file mode 100644
index 00000000..ead05a59
--- /dev/null
+++ b/10/mysql-tomcat/jgroups/udp.xml
@@ -0,0 +1,77 @@
+<!--
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+-->
+
+<!--
+  Default stack using IP multicasting. It is similar to the "udp"
+  stack in stacks.xml, but doesn't use streaming state transfer and flushing
+  author: Bela Ban
+-->
+
+<config xmlns="urn:org:jgroups"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="urn:org:jgroups http://www.jgroups.org/schema/JGroups-3.3.xsd">
+    <UDP
+         bind_addr="match-interface:eth0,match-interface:en0,site_local,loopback"
+
+         mcast_port="${jgroups.udp.mcast_port:45588}"
+         tos="8"
+         ucast_recv_buf_size="5M"
+         ucast_send_buf_size="640K"
+         mcast_recv_buf_size="5M"
+         mcast_send_buf_size="640K"
+         max_bundle_size="64K"
+         ip_ttl="${jgroups.udp.ip_ttl:8}"
+         enable_diagnostics="true"
+         thread_naming_pattern="cl"
+
+         thread_pool.enabled="true"
+         thread_pool.min_threads="2"
+         thread_pool.max_threads="8"
+         thread_pool.keep_alive_time="5000" />
+
+    <PING />
+    <FD_SOCK/>
+    <FD_ALL/>
+    <VERIFY_SUSPECT timeout="1500"  />
+    <BARRIER />
+    <pbcast.NAKACK2 xmit_interval="500"
+                    xmit_table_num_rows="100"
+                    xmit_table_msgs_per_row="2000"
+                    xmit_table_max_compaction_time="30000"
+                    use_mcast_xmit="false"
+                    discard_delivered_msgs="true"/>
+    <UNICAST3 xmit_interval="500"
+              xmit_table_num_rows="100"
+              xmit_table_msgs_per_row="2000"
+              xmit_table_max_compaction_time="60000"
+              conn_expiry_timeout="0"/>
+    <pbcast.STABLE stability_delay="1000" desired_avg_gossip="50000"
+                   max_bytes="4M"/>
+    <pbcast.GMS print_local_addr="true" join_timeout="3000"
+                view_bundling="true"/>
+    <UFC max_credits="2M"
+         min_threshold="0.4"/>
+    <MFC max_credits="2M"
+         min_threshold="0.4"/>
+    <FRAG2 frag_size="60K"  />
+    <RSVP resend_interval="2000" timeout="10000"/>
+    <pbcast.STATE_TRANSFER />
+    <!-- pbcast.FLUSH  /-->
+</config>
diff --git a/10/mysql-tomcat/xwiki/docker-entrypoint.sh b/10/mysql-tomcat/xwiki/docker-entrypoint.sh
index e57a15bd..9726f1f3 100755
--- a/10/mysql-tomcat/xwiki/docker-entrypoint.sh
+++ b/10/mysql-tomcat/xwiki/docker-entrypoint.sh
@@ -39,6 +39,11 @@ function other_starts() {
 function xwiki_replace() {
   sed -i s~"\#\? \?$2 \?=.*"~"$2=$3"~g "$1"
 }
+# $1 - the setting/property to set
+# $2 - the new value
+function xwiki_replace_example() {
+  sed -i s~"\#-# Example:\? \?$1 \?=.*"~"$1=$2"~g "/usr/local/tomcat/webapps/ROOT/WEB-INF/xwiki.properties"
+}
 
 # $1 - the setting/property to set
 # $2 - the new value
@@ -104,6 +109,17 @@ function restoreConfigurationFile() {
   fi
 }
 
+function enableClustering() {
+  echo 'Setting clustering...'
+  xwiki_set_properties 'observation.remote.enabled' 'true'
+  if [ $CLUSTER_CHANNEL ]; then
+    echo "Setting cluster channel to $CLUSTER_CHANNEL"
+    xwiki_replace_example 'observation.remote.channels' "$CLUSTER_CHANNEL"
+  else
+    xwiki_replace_example 'observation.remote.channels' 'udp'
+  fi
+}
+
 function configure() {
   echo 'Configuring XWiki...'
 
@@ -138,6 +154,10 @@ function configure() {
     xwiki_set_properties 'solr.remote.url' "http://$INDEX_HOST:$INDEX_PORT/solr/xwiki"
   fi
 
+  if [ $CLUSTER ]; then 
+    enableClustering
+  fi
+
   # If the files already exist then copy them to the XWiki's WEB-INF directory. Otherwise copy the default config
   # files to the permanent directory so that they can be easily modified by the user. They'll be synced at the next
   # start.
diff --git a/10/postgres-tomcat/Dockerfile b/10/postgres-tomcat/Dockerfile
index 7125c662..43bd886d 100644
--- a/10/postgres-tomcat/Dockerfile
+++ b/10/postgres-tomcat/Dockerfile
@@ -64,6 +64,9 @@ COPY tomcat/setenv.sh /usr/local/tomcat/bin/
 # Setup the XWiki Hibernate configuration
 COPY xwiki/hibernate.cfg.xml /usr/local/tomcat/webapps/ROOT/WEB-INF/hibernate.cfg.xml
 
+# Configure JGroups. 
+COPY jgroups/* /usr/local/tomcat/webapps/ROOT/WEB-INF/observation/remote/jgroups
+
 # Set a specific distribution id in XWiki for this docker packaging.
 RUN sed -i 's/<id>org.xwiki.platform:xwiki-platform-distribution-war/<id>org.xwiki.platform:xwiki-platform-distribution-docker/' \
   /usr/local/tomcat/webapps/ROOT/META-INF/extension.xed
diff --git a/10/postgres-tomcat/jgroups/udp.xml b/10/postgres-tomcat/jgroups/udp.xml
new file mode 100644
index 00000000..ead05a59
--- /dev/null
+++ b/10/postgres-tomcat/jgroups/udp.xml
@@ -0,0 +1,77 @@
+<!--
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+-->
+
+<!--
+  Default stack using IP multicasting. It is similar to the "udp"
+  stack in stacks.xml, but doesn't use streaming state transfer and flushing
+  author: Bela Ban
+-->
+
+<config xmlns="urn:org:jgroups"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="urn:org:jgroups http://www.jgroups.org/schema/JGroups-3.3.xsd">
+    <UDP
+         bind_addr="match-interface:eth0,match-interface:en0,site_local,loopback"
+
+         mcast_port="${jgroups.udp.mcast_port:45588}"
+         tos="8"
+         ucast_recv_buf_size="5M"
+         ucast_send_buf_size="640K"
+         mcast_recv_buf_size="5M"
+         mcast_send_buf_size="640K"
+         max_bundle_size="64K"
+         ip_ttl="${jgroups.udp.ip_ttl:8}"
+         enable_diagnostics="true"
+         thread_naming_pattern="cl"
+
+         thread_pool.enabled="true"
+         thread_pool.min_threads="2"
+         thread_pool.max_threads="8"
+         thread_pool.keep_alive_time="5000" />
+
+    <PING />
+    <FD_SOCK/>
+    <FD_ALL/>
+    <VERIFY_SUSPECT timeout="1500"  />
+    <BARRIER />
+    <pbcast.NAKACK2 xmit_interval="500"
+                    xmit_table_num_rows="100"
+                    xmit_table_msgs_per_row="2000"
+                    xmit_table_max_compaction_time="30000"
+                    use_mcast_xmit="false"
+                    discard_delivered_msgs="true"/>
+    <UNICAST3 xmit_interval="500"
+              xmit_table_num_rows="100"
+              xmit_table_msgs_per_row="2000"
+              xmit_table_max_compaction_time="60000"
+              conn_expiry_timeout="0"/>
+    <pbcast.STABLE stability_delay="1000" desired_avg_gossip="50000"
+                   max_bytes="4M"/>
+    <pbcast.GMS print_local_addr="true" join_timeout="3000"
+                view_bundling="true"/>
+    <UFC max_credits="2M"
+         min_threshold="0.4"/>
+    <MFC max_credits="2M"
+         min_threshold="0.4"/>
+    <FRAG2 frag_size="60K"  />
+    <RSVP resend_interval="2000" timeout="10000"/>
+    <pbcast.STATE_TRANSFER />
+    <!-- pbcast.FLUSH  /-->
+</config>
diff --git a/10/postgres-tomcat/xwiki/docker-entrypoint.sh b/10/postgres-tomcat/xwiki/docker-entrypoint.sh
index e57a15bd..9726f1f3 100755
--- a/10/postgres-tomcat/xwiki/docker-entrypoint.sh
+++ b/10/postgres-tomcat/xwiki/docker-entrypoint.sh
@@ -39,6 +39,11 @@ function other_starts() {
 function xwiki_replace() {
   sed -i s~"\#\? \?$2 \?=.*"~"$2=$3"~g "$1"
 }
+# $1 - the setting/property to set
+# $2 - the new value
+function xwiki_replace_example() {
+  sed -i s~"\#-# Example:\? \?$1 \?=.*"~"$1=$2"~g "/usr/local/tomcat/webapps/ROOT/WEB-INF/xwiki.properties"
+}
 
 # $1 - the setting/property to set
 # $2 - the new value
@@ -104,6 +109,17 @@ function restoreConfigurationFile() {
   fi
 }
 
+function enableClustering() {
+  echo 'Setting clustering...'
+  xwiki_set_properties 'observation.remote.enabled' 'true'
+  if [ $CLUSTER_CHANNEL ]; then
+    echo "Setting cluster channel to $CLUSTER_CHANNEL"
+    xwiki_replace_example 'observation.remote.channels' "$CLUSTER_CHANNEL"
+  else
+    xwiki_replace_example 'observation.remote.channels' 'udp'
+  fi
+}
+
 function configure() {
   echo 'Configuring XWiki...'
 
@@ -138,6 +154,10 @@ function configure() {
     xwiki_set_properties 'solr.remote.url' "http://$INDEX_HOST:$INDEX_PORT/solr/xwiki"
   fi
 
+  if [ $CLUSTER ]; then 
+    enableClustering
+  fi
+
   # If the files already exist then copy them to the XWiki's WEB-INF directory. Otherwise copy the default config
   # files to the permanent directory so that they can be easily modified by the user. They'll be synced at the next
   # start.
diff --git a/11/mysql-tomcat/Dockerfile b/11/mysql-tomcat/Dockerfile
index eacc4b63..02f4fabc 100644
--- a/11/mysql-tomcat/Dockerfile
+++ b/11/mysql-tomcat/Dockerfile
@@ -64,6 +64,9 @@ COPY tomcat/setenv.sh /usr/local/tomcat/bin/
 # Setup the XWiki Hibernate configuration
 COPY xwiki/hibernate.cfg.xml /usr/local/tomcat/webapps/ROOT/WEB-INF/hibernate.cfg.xml
 
+# Configure JGroups. 
+COPY jgroups/* /usr/local/tomcat/webapps/ROOT/WEB-INF/observation/remote/jgroups
+
 # Set a specific distribution id in XWiki for this docker packaging.
 RUN sed -i 's/<id>org.xwiki.platform:xwiki-platform-distribution-war/<id>org.xwiki.platform:xwiki-platform-distribution-docker/' \
   /usr/local/tomcat/webapps/ROOT/META-INF/extension.xed
diff --git a/11/mysql-tomcat/jgroups/udp.xml b/11/mysql-tomcat/jgroups/udp.xml
new file mode 100644
index 00000000..ead05a59
--- /dev/null
+++ b/11/mysql-tomcat/jgroups/udp.xml
@@ -0,0 +1,77 @@
+<!--
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+-->
+
+<!--
+  Default stack using IP multicasting. It is similar to the "udp"
+  stack in stacks.xml, but doesn't use streaming state transfer and flushing
+  author: Bela Ban
+-->
+
+<config xmlns="urn:org:jgroups"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="urn:org:jgroups http://www.jgroups.org/schema/JGroups-3.3.xsd">
+    <UDP
+         bind_addr="match-interface:eth0,match-interface:en0,site_local,loopback"
+
+         mcast_port="${jgroups.udp.mcast_port:45588}"
+         tos="8"
+         ucast_recv_buf_size="5M"
+         ucast_send_buf_size="640K"
+         mcast_recv_buf_size="5M"
+         mcast_send_buf_size="640K"
+         max_bundle_size="64K"
+         ip_ttl="${jgroups.udp.ip_ttl:8}"
+         enable_diagnostics="true"
+         thread_naming_pattern="cl"
+
+         thread_pool.enabled="true"
+         thread_pool.min_threads="2"
+         thread_pool.max_threads="8"
+         thread_pool.keep_alive_time="5000" />
+
+    <PING />
+    <FD_SOCK/>
+    <FD_ALL/>
+    <VERIFY_SUSPECT timeout="1500"  />
+    <BARRIER />
+    <pbcast.NAKACK2 xmit_interval="500"
+                    xmit_table_num_rows="100"
+                    xmit_table_msgs_per_row="2000"
+                    xmit_table_max_compaction_time="30000"
+                    use_mcast_xmit="false"
+                    discard_delivered_msgs="true"/>
+    <UNICAST3 xmit_interval="500"
+              xmit_table_num_rows="100"
+              xmit_table_msgs_per_row="2000"
+              xmit_table_max_compaction_time="60000"
+              conn_expiry_timeout="0"/>
+    <pbcast.STABLE stability_delay="1000" desired_avg_gossip="50000"
+                   max_bytes="4M"/>
+    <pbcast.GMS print_local_addr="true" join_timeout="3000"
+                view_bundling="true"/>
+    <UFC max_credits="2M"
+         min_threshold="0.4"/>
+    <MFC max_credits="2M"
+         min_threshold="0.4"/>
+    <FRAG2 frag_size="60K"  />
+    <RSVP resend_interval="2000" timeout="10000"/>
+    <pbcast.STATE_TRANSFER />
+    <!-- pbcast.FLUSH  /-->
+</config>
diff --git a/11/mysql-tomcat/xwiki/docker-entrypoint.sh b/11/mysql-tomcat/xwiki/docker-entrypoint.sh
index e57a15bd..9726f1f3 100755
--- a/11/mysql-tomcat/xwiki/docker-entrypoint.sh
+++ b/11/mysql-tomcat/xwiki/docker-entrypoint.sh
@@ -39,6 +39,11 @@ function other_starts() {
 function xwiki_replace() {
   sed -i s~"\#\? \?$2 \?=.*"~"$2=$3"~g "$1"
 }
+# $1 - the setting/property to set
+# $2 - the new value
+function xwiki_replace_example() {
+  sed -i s~"\#-# Example:\? \?$1 \?=.*"~"$1=$2"~g "/usr/local/tomcat/webapps/ROOT/WEB-INF/xwiki.properties"
+}
 
 # $1 - the setting/property to set
 # $2 - the new value
@@ -104,6 +109,17 @@ function restoreConfigurationFile() {
   fi
 }
 
+function enableClustering() {
+  echo 'Setting clustering...'
+  xwiki_set_properties 'observation.remote.enabled' 'true'
+  if [ $CLUSTER_CHANNEL ]; then
+    echo "Setting cluster channel to $CLUSTER_CHANNEL"
+    xwiki_replace_example 'observation.remote.channels' "$CLUSTER_CHANNEL"
+  else
+    xwiki_replace_example 'observation.remote.channels' 'udp'
+  fi
+}
+
 function configure() {
   echo 'Configuring XWiki...'
 
@@ -138,6 +154,10 @@ function configure() {
     xwiki_set_properties 'solr.remote.url' "http://$INDEX_HOST:$INDEX_PORT/solr/xwiki"
   fi
 
+  if [ $CLUSTER ]; then 
+    enableClustering
+  fi
+
   # If the files already exist then copy them to the XWiki's WEB-INF directory. Otherwise copy the default config
   # files to the permanent directory so that they can be easily modified by the user. They'll be synced at the next
   # start.
diff --git a/11/postgres-tomcat/Dockerfile b/11/postgres-tomcat/Dockerfile
index 4c5ae32e..b7b18982 100644
--- a/11/postgres-tomcat/Dockerfile
+++ b/11/postgres-tomcat/Dockerfile
@@ -64,6 +64,9 @@ COPY tomcat/setenv.sh /usr/local/tomcat/bin/
 # Setup the XWiki Hibernate configuration
 COPY xwiki/hibernate.cfg.xml /usr/local/tomcat/webapps/ROOT/WEB-INF/hibernate.cfg.xml
 
+# Configure JGroups. 
+COPY jgroups/* /usr/local/tomcat/webapps/ROOT/WEB-INF/observation/remote/jgroups
+
 # Set a specific distribution id in XWiki for this docker packaging.
 RUN sed -i 's/<id>org.xwiki.platform:xwiki-platform-distribution-war/<id>org.xwiki.platform:xwiki-platform-distribution-docker/' \
   /usr/local/tomcat/webapps/ROOT/META-INF/extension.xed
diff --git a/11/postgres-tomcat/jgroups/udp.xml b/11/postgres-tomcat/jgroups/udp.xml
new file mode 100644
index 00000000..ead05a59
--- /dev/null
+++ b/11/postgres-tomcat/jgroups/udp.xml
@@ -0,0 +1,77 @@
+<!--
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+-->
+
+<!--
+  Default stack using IP multicasting. It is similar to the "udp"
+  stack in stacks.xml, but doesn't use streaming state transfer and flushing
+  author: Bela Ban
+-->
+
+<config xmlns="urn:org:jgroups"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="urn:org:jgroups http://www.jgroups.org/schema/JGroups-3.3.xsd">
+    <UDP
+         bind_addr="match-interface:eth0,match-interface:en0,site_local,loopback"
+
+         mcast_port="${jgroups.udp.mcast_port:45588}"
+         tos="8"
+         ucast_recv_buf_size="5M"
+         ucast_send_buf_size="640K"
+         mcast_recv_buf_size="5M"
+         mcast_send_buf_size="640K"
+         max_bundle_size="64K"
+         ip_ttl="${jgroups.udp.ip_ttl:8}"
+         enable_diagnostics="true"
+         thread_naming_pattern="cl"
+
+         thread_pool.enabled="true"
+         thread_pool.min_threads="2"
+         thread_pool.max_threads="8"
+         thread_pool.keep_alive_time="5000" />
+
+    <PING />
+    <FD_SOCK/>
+    <FD_ALL/>
+    <VERIFY_SUSPECT timeout="1500"  />
+    <BARRIER />
+    <pbcast.NAKACK2 xmit_interval="500"
+                    xmit_table_num_rows="100"
+                    xmit_table_msgs_per_row="2000"
+                    xmit_table_max_compaction_time="30000"
+                    use_mcast_xmit="false"
+                    discard_delivered_msgs="true"/>
+    <UNICAST3 xmit_interval="500"
+              xmit_table_num_rows="100"
+              xmit_table_msgs_per_row="2000"
+              xmit_table_max_compaction_time="60000"
+              conn_expiry_timeout="0"/>
+    <pbcast.STABLE stability_delay="1000" desired_avg_gossip="50000"
+                   max_bytes="4M"/>
+    <pbcast.GMS print_local_addr="true" join_timeout="3000"
+                view_bundling="true"/>
+    <UFC max_credits="2M"
+         min_threshold="0.4"/>
+    <MFC max_credits="2M"
+         min_threshold="0.4"/>
+    <FRAG2 frag_size="60K"  />
+    <RSVP resend_interval="2000" timeout="10000"/>
+    <pbcast.STATE_TRANSFER />
+    <!-- pbcast.FLUSH  /-->
+</config>
diff --git a/11/postgres-tomcat/xwiki/docker-entrypoint.sh b/11/postgres-tomcat/xwiki/docker-entrypoint.sh
index e57a15bd..9726f1f3 100755
--- a/11/postgres-tomcat/xwiki/docker-entrypoint.sh
+++ b/11/postgres-tomcat/xwiki/docker-entrypoint.sh
@@ -39,6 +39,11 @@ function other_starts() {
 function xwiki_replace() {
   sed -i s~"\#\? \?$2 \?=.*"~"$2=$3"~g "$1"
 }
+# $1 - the setting/property to set
+# $2 - the new value
+function xwiki_replace_example() {
+  sed -i s~"\#-# Example:\? \?$1 \?=.*"~"$1=$2"~g "/usr/local/tomcat/webapps/ROOT/WEB-INF/xwiki.properties"
+}
 
 # $1 - the setting/property to set
 # $2 - the new value
@@ -104,6 +109,17 @@ function restoreConfigurationFile() {
   fi
 }
 
+function enableClustering() {
+  echo 'Setting clustering...'
+  xwiki_set_properties 'observation.remote.enabled' 'true'
+  if [ $CLUSTER_CHANNEL ]; then
+    echo "Setting cluster channel to $CLUSTER_CHANNEL"
+    xwiki_replace_example 'observation.remote.channels' "$CLUSTER_CHANNEL"
+  else
+    xwiki_replace_example 'observation.remote.channels' 'udp'
+  fi
+}
+
 function configure() {
   echo 'Configuring XWiki...'
 
@@ -138,6 +154,10 @@ function configure() {
     xwiki_set_properties 'solr.remote.url' "http://$INDEX_HOST:$INDEX_PORT/solr/xwiki"
   fi
 
+  if [ $CLUSTER ]; then 
+    enableClustering
+  fi
+
   # If the files already exist then copy them to the XWiki's WEB-INF directory. Otherwise copy the default config
   # files to the permanent directory so that they can be easily modified by the user. They'll be synced at the next
   # start.
diff --git a/README.md b/README.md
index 665b25fb..43a89c41 100644
--- a/README.md
+++ b/README.md
@@ -361,6 +361,82 @@ secrets:
       name: xwiki-db-root-password
 ```
 
+## Configuring clustering
+
+Read about [setting communication channels](https://www.xwiki.org/xwiki/bin/view/Documentation/AdminGuide/Clustering/).
+
+#### Docker Compose example
+
+```yaml
+
+version: '2'
+networks:
+  bridge:
+    driver: bridge
+services:
+  web1:
+    build: .
+    container_name: xwiki-postgres-tomcat-web
+    depends_on:
+      - db
+    ports:
+      - "8080:8080"
+    environment:
+      - XWIKI_VERSION=${XWIKI_VERSION}
+      - DB_USER=${DB_USER}
+      - DB_PASSWORD=${DB_PASSWORD}
+      - DB_DATABASE=${DB_DATABASE}
+      - DB_HOST=xwiki-postgres-db
+      - CLUSTER=true
+      - CLUSTER_CHANNEL=udp
+    volumes:
+      - xwiki-data-cache:/usr/local/xwiki/data/cache
+      - xwiki-data-jobs:/usr/local/xwiki/data/jobs
+      - xwiki-data-extension:/usr/local/xwiki/data/extension
+    networks:
+      - bridge
+  web2:
+    build: .
+    container_name: xwiki-postgres-tomcat-web2
+    depends_on:
+      - db
+    ports:
+      - "8081:8080"
+    environment:
+      - XWIKI_VERSION=${XWIKI_VERSION}
+      - DB_USER=${DB_USER}
+      - DB_PASSWORD=${DB_PASSWORD}
+      - DB_DATABASE=${DB_DATABASE}
+      - DB_HOST=xwiki-postgres-db
+      - CLUSTER=true
+      - CLUSTER_CHANNEL=udp
+    volumes:
+      - xwiki-data-cache:/usr/local/xwiki/data/cache
+      - xwiki-data-jobs:/usr/local/xwiki/data/jobs
+      - xwiki-data-extension:/usr/local/xwiki/data/extension
+    networks:
+      - bridge
+  db:
+    image: "postgres:9.5-alpine"
+    container_name: xwiki-postgres-db
+    volumes:
+      - postgres-data:/var/lib/postgresql/data
+    environment:
+      - POSTGRES_ROOT_PASSWORD=${POSTGRES_ROOT_PASSWORD}
+      - POSTGRES_PASSWORD=${DB_PASSWORD}
+      - POSTGRES_USER=${DB_USER}
+      - POSTGRES_DB=${DB_DATABASE}
+      - POSTGRES_INITDB_ARGS="--encoding=UTF8"
+    networks:
+      - bridge
+volumes:
+  postgres-data: {}
+  xwiki-data-cache: {}
+  xwiki-data-jobs: {}
+  xwiki-data-extension: {}
+```
+
+
 ## Using an external Solr service
 
 From the [XWiki Solr Search API documentation](https://extensions.xwiki.org/xwiki/bin/view/Extension/Solr%20Search%20API):
@@ -516,6 +592,8 @@ The first time you create a container out of the xwiki image, a shell script (`/
 -	`DB_HOST`: The name of the host (or docker container) containing the database. Default is "db".
 -	`INDEX_HOST`: The hostname of an externally configured Solr instance. Defaults to "localhost", and configures an embedded Solr instance.
 -	`INDEX_PORT`: The port used by an externally configured Solr instance. Defaults to 8983.
+- `CLUSTER`: Set it to "true" to enable clustering.
+- `CLUSTER_CHANNEL`: The JGroups channel name.
 
 In order to support [Docker secrets](https://docs.docker.com/engine/swarm/secrets/), these configuration values can also be given to the container as files containing that value.
 
diff --git a/build.gradle b/build.gradle
index 66ab9999..ec1fbe3f 100644
--- a/build.gradle
+++ b/build.gradle
@@ -79,6 +79,13 @@ task generate() {
                     expand(tokens[version])
                     filteringCharset = 'UTF-8'
                 }
+                // Copy JGroups files
+                copy {
+                    from 'template'
+                    into "${version}/${variant}"
+                    include "jgroups/*"
+                    filteringCharset = 'UTF-8'
+                }
             }
         }
     }
diff --git a/template/Dockerfile b/template/Dockerfile
index 1a7546e4..af558e75 100644
--- a/template/Dockerfile
+++ b/template/Dockerfile
@@ -72,6 +72,9 @@ COPY tomcat/setenv.sh /usr/local/tomcat/bin/
 # Setup the XWiki Hibernate configuration
 COPY xwiki/hibernate.cfg.xml /usr/local/tomcat/webapps/ROOT/WEB-INF/hibernate.cfg.xml
 
+# Configure JGroups. 
+COPY jgroups/* /usr/local/tomcat/webapps/ROOT/WEB-INF/observation/remote/jgroups
+
 # Set a specific distribution id in XWiki for this docker packaging.
 RUN sed -i \'s/<id>org.xwiki.platform:xwiki-platform-distribution-war/<id>org.xwiki.platform:xwiki-platform-distribution-docker/\' \\
   /usr/local/tomcat/webapps/ROOT/META-INF/extension.xed
diff --git a/template/jgroups/udp.xml b/template/jgroups/udp.xml
new file mode 100644
index 00000000..ead05a59
--- /dev/null
+++ b/template/jgroups/udp.xml
@@ -0,0 +1,77 @@
+<!--
+ * See the NOTICE file distributed with this work for additional
+ * information regarding copyright ownership.
+ *
+ * This is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this software; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
+-->
+
+<!--
+  Default stack using IP multicasting. It is similar to the "udp"
+  stack in stacks.xml, but doesn't use streaming state transfer and flushing
+  author: Bela Ban
+-->
+
+<config xmlns="urn:org:jgroups"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="urn:org:jgroups http://www.jgroups.org/schema/JGroups-3.3.xsd">
+    <UDP
+         bind_addr="match-interface:eth0,match-interface:en0,site_local,loopback"
+
+         mcast_port="${jgroups.udp.mcast_port:45588}"
+         tos="8"
+         ucast_recv_buf_size="5M"
+         ucast_send_buf_size="640K"
+         mcast_recv_buf_size="5M"
+         mcast_send_buf_size="640K"
+         max_bundle_size="64K"
+         ip_ttl="${jgroups.udp.ip_ttl:8}"
+         enable_diagnostics="true"
+         thread_naming_pattern="cl"
+
+         thread_pool.enabled="true"
+         thread_pool.min_threads="2"
+         thread_pool.max_threads="8"
+         thread_pool.keep_alive_time="5000" />
+
+    <PING />
+    <FD_SOCK/>
+    <FD_ALL/>
+    <VERIFY_SUSPECT timeout="1500"  />
+    <BARRIER />
+    <pbcast.NAKACK2 xmit_interval="500"
+                    xmit_table_num_rows="100"
+                    xmit_table_msgs_per_row="2000"
+                    xmit_table_max_compaction_time="30000"
+                    use_mcast_xmit="false"
+                    discard_delivered_msgs="true"/>
+    <UNICAST3 xmit_interval="500"
+              xmit_table_num_rows="100"
+              xmit_table_msgs_per_row="2000"
+              xmit_table_max_compaction_time="60000"
+              conn_expiry_timeout="0"/>
+    <pbcast.STABLE stability_delay="1000" desired_avg_gossip="50000"
+                   max_bytes="4M"/>
+    <pbcast.GMS print_local_addr="true" join_timeout="3000"
+                view_bundling="true"/>
+    <UFC max_credits="2M"
+         min_threshold="0.4"/>
+    <MFC max_credits="2M"
+         min_threshold="0.4"/>
+    <FRAG2 frag_size="60K"  />
+    <RSVP resend_interval="2000" timeout="10000"/>
+    <pbcast.STATE_TRANSFER />
+    <!-- pbcast.FLUSH  /-->
+</config>
diff --git a/template/xwiki/docker-entrypoint.sh b/template/xwiki/docker-entrypoint.sh
index f1581198..5cdd0186 100755
--- a/template/xwiki/docker-entrypoint.sh
+++ b/template/xwiki/docker-entrypoint.sh
@@ -39,6 +39,11 @@ function other_starts() {
 function xwiki_replace() {
   sed -i s~"\\#\\? \\?\$2 \\?=.*"~"\$2=\$3"~g "\$1"
 }
+# \$1 - the setting/property to set
+# \$2 - the new value
+function xwiki_replace_example() {
+  sed -i s~"\\#-# Example:\\? \\?\$1 \\?=.*"~"\$1=\$2"~g "/usr/local/tomcat/webapps/ROOT/WEB-INF/xwiki.properties"
+}
 
 # \$1 - the setting/property to set
 # \$2 - the new value
@@ -104,6 +109,17 @@ function restoreConfigurationFile() {
   fi
 }
 
+function enableClustering() {
+  echo 'Setting clustering...'
+  xwiki_set_properties 'observation.remote.enabled' 'true'
+  if [ \$CLUSTER_CHANNEL ]; then
+    echo "Setting cluster channel to \$CLUSTER_CHANNEL"
+    xwiki_replace_example 'observation.remote.channels' "\$CLUSTER_CHANNEL"
+  else
+    xwiki_replace_example 'observation.remote.channels' 'udp'
+  fi
+}
+
 function configure() {
   echo 'Configuring XWiki...'
 
@@ -138,6 +154,10 @@ function configure() {
     xwiki_set_properties 'solr.remote.url' "http://\$INDEX_HOST:\$INDEX_PORT/solr/xwiki"
   fi
 
+  if [ \$CLUSTER ]; then 
+    enableClustering
+  fi
+
   # If the files already exist then copy them to the XWiki's WEB-INF directory. Otherwise copy the default config
   # files to the permanent directory so that they can be easily modified by the user. They'll be synced at the next
   # start.