Introduction

Overview

This document is intended to describe the steps required to deploy Joget DX 8 Enterprise Edition in a clustered environment for scalability and redundancy.


Requirements

Starting from Joget DX 8, Large Enterprise Edition is no longer required for clustering to work. The Enterprise Edition has been enhanced to integrate the clustering feature. Clustering requires several layers to be prepared and configured:

  • Load Balancers

  • Application Servers

  • Shared File Directory

  • Shared Database

Architecture

There are many ways to design the clustering architecture, but the core concepts will be similar. In this document, the architecture used is as follows:

Deployment and Configuration Guide

This guide describes the steps required to setup Joget clustering. The exact steps will depend on the actual products used in each layer.

IMPORTANT: Please note that there is minimal configuration required in Joget LEE itself, and almost all the work is done on the separate layers so it is vital to ensure that you have sufficient expertise in your chosen products.


Pre-Deployment Requirements

Before the clustering installation can be done, the following prerequisites are needed:

Shared file directory

Common directory to be accessed by the application servers with read/write permissions. This directory is used to store shared configuration files, system generated files, and uploaded files. Verify that the shared directory is mounted on the application servers and that files can be accessed with read and write permissions.

Shared database

Common database to be accessed by the application servers with permission to select, update, delete, create and alter tables. Verify that the application servers can connect and query the shared database.

Application servers

Java web application server to be installed and running on each server in the cluster. Verify that each application server has been installed correctly and can be accessed with a web browser.

Session replication

Session replication to be configured on the application servers and network. Verify that session replication has been configured for each application server and the network.

Load balancer

Load balancer (hardware or software) to be installed and configured to direct traffic for requests beginning with /jw to the application servers. Verify that the load balancer has been installed and configured correctly so that web traffic is directed to the individual application servers.

Joget Clustering Configuration

It is important to ensure that the pre-deployment requirements have been verified. Once verified, the Joget specific steps are as follows:

Datasource Configuration

Configure the datasource properties files in the shared directory

  1. Copy all the files and directories from the wflow directory of a Joget LEE bundle into the shared file directory.

  2. Edit app_datasource-default.properties and set the database connection settings for the shared database, e.g. for MySQL, change the bold values below:



workflowDriver=com.mysql.jdbc.Driver
workflowUrl=jdbc\:mysql\://host\:port/database_name?characterEncoding\=UTF-8
workflowUser=username
profileName=
workflowPassword=password

Application Deployment and Configuration

Deploy the Joget WAR file to the application servers and configure the startup properties to point to the shared directory.

  1. Deploy the WAR file jw.war from the Joget installation bundle to each of the application servers e.g. for Apache Tomcat, copy the files into the webapps directory

  2. For Joget DX 8, the wflow-cluster.jar file is already included and configured in the default startup script. Modify the JAVA_OPTS in the startup script if necessary (particularly regarding the shared directory path).

export JAVA_OPTS="-Xmx1024M -Dwflow.home=/shared_directory_path -javaagent:/shared_directory_path/wflow-cluster.jar -javaagent:/path_to/lib/aspectjweaver-1.9.7.jar -javaagent:/shared_directory_path/glowroot/glowroot.jar"

Please note that -Dwflow.name= is optional, but it is required if your nodes are in the same server. -Dwflow.name= must be placed before -javaagent:/shared_directory_path/wflow-cluster.jar.

Example: -Dwflow.name=node1


License Activation

Activate license for each server. Each server has a unique system key and requires a separate license activation.

For more info about license activation, see Activate your Joget DX Enterprise License.

  1. For each of the application servers, use the browser to directly access the Joget web console bypassing the load balancer e.g. http://server1:8080/jw/web/console/home

  2. Request for license and activate it using the link in the web console footer.


Post-Deployment Testing

Once the pre-deployment and clustering configuration has been done, the testing is a matter of using a web browser to access the load balancer.

Sample Installation and Configuration


This sample describes an installation using the following products:

Joget

Joget DX 8 EE

Load Balancer

Apache HTTP Web Server 2.4 with mod_proxy and mod_balancer (proxy and load balancing modules) running on Ubuntu 18.04

Application Servers

Apache Tomcat 8.5 running on Ubuntu 18.04

Shared File Directory

NFS on Ubuntu 18.04

Shared Database

MySQL 5.7 on Ubuntu 18.04

IMPORTANT: Please note that this is not a comprehensive guide and does not cover production-level requirements e.g. user permissions, network and database security, etc. Please ensure that these are covered by your system, network and database administrators.

Create a Shared File Directory

Share a file directory to be accessed by the application servers. This directory is used to store configuration files, system generated files, and uploaded files.
In this sample, the shared file directory will be a directory /export/wflow in the file server

In the file server, install the NFS server

sudo apt-get install portmap nfs-kernel-server

Create shared directory and set permission

sudo mkdir -p /export/wflow
sudo chown nobody:nogroup /export/wflow

Configure NFS to export the shared directory, edit /etc/exports to export the directory to the local 192.168.1.0 subnetwork with your favourite editor

sudo vim /etc/exports

The /etc/exports should contain the following:

/export/wflow 192.168.1.0/255.255.255.0(rw,no_subtree_check,async)

Export the shares and restart NFS service

sudo exportfs -ra
sudo service nfs-kernel-server restart


Mount the Shared Directory in the Application Servers

In the application servers, install the NFS client

apt-get install nfs-common

Create new directory /opt/joget/shared/wflow to mount the shared directory and set the directory permissions

sudo mkdir -p /opt/joget/shared/wflow
sudo chmod 777 /opt/joget/shared/wflow

Mount the shared directory.

sudo mount -t nfs wflow:/export/wflow /opt/joget/shared/wflow

Test read-write permissions to confirm that the directory sharing works.

echo test123 > /opt/joget/shared/wflow/test.txt

Create a Shared Database

Install MySQL ( https://help.ubuntu.com/18.04/serverguide/mysql.html)

sudo apt-get install mysql-server

Create a database called jwedb accessible to the application servers.

mysql -u root

Run the following MySQL commands to create a blank database

create database jwedb;
quit

Populate the newly created database with the Joget database schema

mysql -uroot jwedb < /path/to/jwdb-mysql.sql

Configure database permissions

mysql -u root

Run the following MySQL commands to grant permissions to user joget and password joget

grant all privileges on jwedb.* to 'joget'@'%' identified by 'joget';
flush privileges;
quit

Configure MySQL to listen to database connections from remote hosts. Edit the my.cnf file with your favourite editor

sudo vim /etc/mysql/my.cnf

Comment away the bind-address directive by adding a # in front of the line

#bind-address = 127.0.0.1

Restart MySQL

sudo service mysql restart

In the application server, test a remote connection to the database server database_host

mysql -h database_host -u joget -p



Deploy Application Servers

Install Apache Tomcat on each of the application servers. In each application server, run the following to extract tomcat into /opt/joget:

sudo mkdir -p /opt/joget/
sudo tar xvfz apache-tomcat-8.5.41.tar.gz /opt/joget/

Start each application server

sudo cd /opt/joget/apache-tomcat-8.5.41
sudo ./bin/catalina.sh start

Open a web browser and access each server to confirm that http://server:8080/jw



Configure Application Server Session Replication

Configure Tomcat for clustering by editing apache-tomcat-8.5.41/conf/server.xml. Add jvmRoute="node01" to the Engine tag and uncomment the Cluster tag.

<Engine name="Catalina" defaultHost="localhost" jvmRoute="node01">
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>

Configure local domain IP. Verify that the local server name resolves to the IP and not 127.0.1.1. Assuming the server name is server1 and the IP is 192.168.1.10, edit /etc/hosts and set:

192.168.1.10 server1

Verify multicast is enabled between the application servers by running ifconfig and look for MULTICAST. Try http://blogs.agilefaqs.com/2009/11/08/enabling-multicast-on-your-macos-unix/ if there are issues.

Restart the Tomcat servers.

sudo cd /opt/joget/apache-tomcat-8.5.41
sudo ./bin/catalina.sh stop
sudo ./bin/catalina.sh start

Verify session replication working between the application servers. The catalina.out log file in apache-tomcat-8.5.41/logs should show something similar to:

INFO: Starting clustering manager at localhost#/jw
Jan 17, 2016 11:21:32 AM org.apache.catalina.ha.session.DeltaManager getAllClusterSessions
INFO: Manager [localhost#/jw], requesting session state from org.apache.catalina.tribes.membership.MemberImpl[tcp://{127, 0, 0, 1}:4001,{127, 0, 0, 1},4001, alive=55733886, securePort=-1, UDP Port=-1, id={-57 118 -98 -98 110 -38 64 -68 -74 -25 -29 101 46 103 5 -48 }, payload={}, command={}, domain={}, ]. This operation will timeout if no session state has been received within 60 seconds.
Jan 17, 2016 11:21:32 AM org.apache.catalina.ha.session.DeltaManager waitForSendAllSessions
INFO: Manager [localhost#/jw]; session state send at 1/17/16 11:21 AM received in 104 ms.

More information on Tomcat clustering is at http://tomcat.apache.org/tomcat-8.5-doc/cluster-howto.html


Configure Load Balancer

In the load balancer server, install Apache HTTP Server 

sudo apt-get install apache2

Install proxy and balancer modules

sudo a2enmod headers proxy proxy_balancer proxy_http

If you are running Apache 2.4, you will need to also enable the following module.

sudo a2enmod lbmethod_byrequests


Configure a new site with the proxy and balancer modules. Create a new file in /etc/apache2/sites-available, named jwsite

sudo vim /etc/apache2/sites-available/jwsite.conf

Add the contents

NameVirtualHost *
<VirtualHost *>
	DocumentRoot "/var/www/jwsite" 
	ServerName localhost
	ServerAdmin support@example.com
 	ErrorLog /var/log/apache2/jwsite-error.log
    CustomLog /var/log/apache2/jwsite-access.log combined
	DirectoryIndex index.html index.htm 
	<Proxy balancer://wscluster>
		BalancerMember ws://server1:8080 route=node01
		BalancerMember ws://server2:8080 route=node02
		Order deny,allow
		Allow from all
	</Proxy>
	ProxyPass /jw/web/applog balancer://wscluster/jw/web/applog stickysession=JSESSIONID|jsessionid
	ProxyPassReverse /jw/web/applog balancer://wscluster/jw/web/applog
	<Proxy balancer://cluster>
		BalancerMember http://server1:8080 route=node01
		BalancerMember http://server2:8080 route=node02
		Order deny,allow
		Allow from all
	</Proxy> 
	ProxyPass /jw balancer://cluster/jw stickysession=JSESSIONID|jsessionid
	ProxyPassReverse /jw balancer://cluster/jw
	ProxyPreserveHost On
</VirtualHost>

Enable the new site and restart Apache

sudo a2ensite jwsite
sudo service apache2 reload



Deploy and Configure Joget LEE

Deploy and configure Joget LEE as described earlier in 2.2 Joget Clustering Configuration


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