Introduction

Overview

This document is intended to describe the steps required to deploy Joget Workflow Large Enterprise Edition (LEE) in a clustered environment for scalability and redundancy.

Requirements

In order for clustering to work, the Large Enterprise Edition is required. The standard Enterprise Edition will not work due to licensing restrictions. 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 Workflow LEE clustering. The exact steps will depend on the actual products used in each layer.

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 Workflow Clustering Configuration

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

Datasource Configuration

Configure the datasource properties files in the shared directory

1. Copy the files app_datasource.properties and app_datasource-default.properties from the wflow directory of a standard Joget installation 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 Joget WAR files to the application servers and configure the startup properties to point to the shared directory.

1. Deploy the WAR files jw.war and jwdesigner.war from the LEE bundle to each of the application servers, e.g. for Apache Tomcat, copy the files into the tomcat webapps directory
2. Add a Java -wflow.home=shared_directory_path option in the application server startup e.g. for Apache Tomcat, modify the JAVA_OPTS line
   
   

export JAVA_OPTS="-XX:MaxPermSize=128m -Xmx1024M -Dwflow.home=/shared_directory_path"

License Activation

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

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:

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/14.04/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-8.0.20.tar.gz /opt/joget/

Start each application server

sudo cd /opt/joget/apache-tomcat-8.0.20
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-8.0.20/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-8.0.20
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-8.0.20/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-8.0-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@mycompany.com
 	ErrorLog /var/www/jwsite/logs/error.log
    CustomLog /var/www/jwsite/logs/access.log combined
	DirectoryIndex index.html index.htm 
	<Proxy balancer://cluster>
		BalancerMember http://server1:8080 route=node01
		BalancerMember http://server2:8080 route=node02
		Order deny,allow
		Allow from all
	</Proxy> 
	ProxyPreserveHost On
	ProxyPass /jw balancer://cluster/jw stickysession=JSESSIONID
	ProxyPassReverse /jw balancer://cluster/jw
</VirtualHost>

Enable the new site and restart Apache

sudo a2ensite jwsite
sudo service apache2 reload

Deploy and Configure Joget Workflow LEE

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