How to configure Hazelcast for session caching using spring while limiting it to a set of nodes?

spring session spring-mvc hazelcast

16,228

Solution 1

Thank you for the suggested answer. However, I think I've solved this using the following configuration. I would appreciate any feedback from anyone about this configuration.

My approach:

1) Establish the instance with a spring configuration. 2) Enhance the instance with a minimally configured hazelcast.xml file with the Web filter configuration. Note that mulitcast and tcp-ip joiners are false.

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" 
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

<!-- The definition of the Root Spring Container shared by all Servlets and Filters -->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/spring/servlet-context.xml,
            /WEB-INF/spring/root-context.xml,
            ....
            /WEB-INF/spring/hazelcastContext.xml
        </param-value>
    </context-param>


<listener>

    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>

</listener>
....

<filter>
    <filter-name>hazelcast-filter</filter-name>
    <filter-class>com.hazelcast.web.WebFilter</filter-class>
    <!--
        Name of the distributed map storing
        your web session objects
    -->
    <init-param>
        <param-name>map-name</param-name>
        <param-value>my-sessions</param-value>
    </init-param>
    <!--
        How is your load-balancer configured?
        stick-session means all requests of a session
        is routed to the node where the session is first created.
        This is excellent for performance.
        If sticky-session is set to false, when a session is updated
        on a node, entry for this session on all other nodes is invalidated.
        You have to know how your load-balancer is configured before
        setting this parameter. Default is true.
    -->
    <init-param>
        <param-name>sticky-session</param-name>
        <param-value>true</param-value>
    </init-param>
    <!--
        Name of session id cookie
    -->
    <init-param>
        <param-name>cookie-name</param-name>
        <param-value>hazelcast.sessionId</param-value>
    </init-param>
    <!--
        Domain of session id cookie. Default is based on incoming request.
    -->
    <init-param>
        <param-name>cookie-domain</param-name>
        <param-value>.mycompany.com</param-value>
    </init-param>
    <!--
        Should cookie only be sent using a secure protocol? Default is false.
    -->
    <init-param>
        <param-name>cookie-secure</param-name>
        <param-value>false</param-value>
    </init-param>
    <!--
        Should HttpOnly attribute be set on cookie ? Default is false.
    -->
    <init-param>
        <param-name>cookie-http-only</param-name>
        <param-value>false</param-value>
    </init-param>
    <!--
        Are you debugging? Default is false.
    -->
    <init-param>
        <param-name>debug</param-name>
        <param-value>true</param-value>
    </init-param>
    <!--
        Configuration xml location;
            * as servlet resource OR
            * as classpath resource OR
            * as URL
        Default is one of hazelcast-default.xml
        or hazelcast.xml in classpath.
    -->

    <init-param>
        <param-name>config-location</param-name>
        <param-value>/WEB-INF/classes/hazelcast.xml</param-value>
    </init-param>

    <!--
        Do you want to use an existing HazelcastInstance?
        Default is null.
    -->`enter code here`
    <init-param>
        <param-name>instance-name</param-name>
        <param-value>myapp</param-value>
    </init-param>
    <!--
        Do you want to connect as a client to an existing cluster?
        Default is false.
    -->
    <init-param>
        <param-name>use-client</param-name>
        <param-value>false</param-value>
    </init-param>
    <!--
        Client configuration location;
            * as servlet resource OR
            * as classpath resource OR
            * as URL
        Default is null.
    -->
    <init-param>
        <param-name>client-config-location</param-name>
        <param-value>/WEB-INF/classes/hazelcast-client.properties</param-value>
    </init-param>
        <!--
            Do you want to shutdown HazelcastInstance during
            web application undeploy process?
            Default is true.
        -->
        <init-param>
            <param-name>shutdown-on-destroy</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>hazelcast-filter</filter-name>
        <url-pattern>/*</url-pattern>
        <dispatcher>FORWARD</dispatcher>
        <dispatcher>INCLUDE</dispatcher>
        <dispatcher>REQUEST</dispatcher>
    </filter-mapping>

...

</web-app>

hazelcast.xml (copied from hazelcast.xml inside jar file)...

<hazelcast xsi:schemaLocation="http://www.hazelcast.com/schema/config hazelcast-config-2.4.xsd"
           xmlns="http://www.hazelcast.com/schema/config"
           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">

...
<network>
    <port auto-increment="true">5701</port>
    <outbound-ports>
        <!--
        Allowed port range when connecting to other nodes.
        0 or * means use system provided port.
        -->
        <ports>0</ports>
    </outbound-ports>
    <join>
        <multicast enabled="false">
            <multicast-group>224.2.2.3</multicast-group>
            <multicast-port>54327</multicast-port>
        </multicast>
        <tcp-ip enabled="false">
            <interface>127.0.0.1</interface>
        </tcp-ip>
 ...
    </join>
 ...
</network>

...  

</hazelcast>

Spring config....

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:hz="http://www.hazelcast.com/schema/spring"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.hazelcast.com/schema/spring
http://www.hazelcast.com/schema/spring/hazelcast-spring-2.4.xsd">


<bean id="hazelcast" class="com.hazelcast.core.Hazelcast" />

<!-- Hazelcast Instance configuration -->
<hz:hazelcast id="myapp">
    <hz:config>
        <!-- Hazelcast Instance Name -->
        <hz:instance-name>${hz.instance.name}</hz:instance-name>
        <!-- Hazelcast Group Name and Password -->
        <hz:group name="${hz.group.name}" password="${hz.group.password}" />
        <!-- Hazelcast Management Center URL -->
        <hz:management-center enabled="${hz.management.center.enabled}" url="${hz.management.center.url}" />
        <!-- Hazelcast Tcp based network configuration -->
        <hz:network port="${hz.network.port}" port-auto-increment="${hz.network.port.auto.increment}">
            <hz:join>
                <hz:multicast enabled="${hz.multicast.enabled}" multicast-group="224.2.2.3" multicast-port="54327" />
                <hz:tcp-ip enabled="${hz.tcp.ip.enabled}">
                    <hz:members>${hz.members}</hz:members>
                </hz:tcp-ip>
            </hz:join>
        </hz:network>
        <!-- Hazelcast Distributed Map configuration -->
        <hz:map name="map" backup-count="${hz.map.backup.count}" max-size="${hz.map.max.size}" eviction-percentage="${hz.map.eviction.percentage}"
            read-backup-data="${hz.map.read.backup.data}" eviction-policy="${hz.map.eviction.policy}" merge-policy="${hz.map.merge.policy}" />
    </hz:config>
</hz:hazelcast>

Property file....

#-- Hazelcast properties.
hz.instance.name = myapp
hz.group.name = CERT
hz.group.password = cert
hz.management.center.enabled = true
hz.management.center.url = http://127.0.0.1:8080/mancenter
hz.network.port = 5701
hz.network.port.auto.increment = true
hz.multicast.enabled = true
hz.tcp.ip.enabled = false
hz.members = 127.0.0.1
hz.executor.service.core.pool.size = 2
hz.executor.service.max.pool.size = 30
hz.executor.service.keep.alive.seconds = 30
hz.map.backup.count=2
hz.map.max.size=0
hz.map.eviction.percentage=30
hz.map.read.backup.data=true
hz.map.cache.value=true
hz.map.eviction.policy=NONE
hz.map.merge.policy=hz.ADD_NEW_ENTRY

Root Context.xml

<beans xmlns="http://www.springframework.org/schema/beans" 
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:hz="http://www.hazelcast.com/schema/spring"
    xmlns:jee="http://www.springframework.org/schema/jee" 
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
    http://www.springframework.org/schema/context 
    http://www.springframework.org/schema/context/spring-context-3.1.xsd
    http://www.springframework.org/schema/jee 
    http://www.springframework.org/schema/jee/spring-jee-3.1.xsd
    http://www.hazelcast.com/schema/spring
    http://www.hazelcast.com/schema/spring/hazelcast-spring-2.4.xsd">


...

    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <jee:jndi-lookup jndi-name="java:comp/env/config_file" />
            </list>
        </property>
    </bean>

...

</beans>

Tomcat Config...

<Host appBase="webapps" autoDeploy="true" name="localhost" unpackWARs="true">
...

    <Context docBase="myapp" path="/myapp" reloadable="true"  source="org.eclipse.jst.j2ee.server:pwc-ws">
                    <Environment description="" name="config_file" override="false" type="java.lang.String" value="file:c:/path/to/config/myapp.properties" />
        </Context>
...

</Host>

Tomcat output (Note: This is a restart scenario of a two node hazelcast group. In this scenario, Node 1 is restarted. The output of Node 2 shows the drop of node 1 from the group and then its return to the group).

Node 1 of Group CERT

Nov 19, 2013 4:27:56 PM com.hazelcast.impl.AddressPicker
INFO: Prefer IPv4 stack is true.
Nov 19, 2013 4:27:56 PM com.hazelcast.impl.AddressPicker
INFO: Picked Address[10.23.43.13]:5701, using socket ServerSocket[addr=/0:0:0:0:0:0:0:0,localport=5701], bind any local is true
Nov 19, 2013 4:27:57 PM com.hazelcast.system
INFO: [10.23.43.13]:5701 [CERT] Hazelcast Community Edition 2.4 (20121017) starting at Address[10.23.43.13]:5701
Nov 19, 2013 4:27:57 PM com.hazelcast.system
INFO: [10.23.43.13]:5701 [CERT] Copyright (C) 2008-2012 Hazelcast.com
Nov 19, 2013 4:27:57 PM com.hazelcast.impl.LifecycleServiceImpl
INFO: [10.23.43.13]:5701 [CERT] Address[10.23.43.13]:5701 is STARTING
Nov 19, 2013 4:27:57 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:27:57 PM com.hazelcast.impl.MulticastJoiner
INFO: [10.23.43.13]:5701 [CERT] Connecting to master node: Address[10.23.43.14]:5701
Nov 19, 2013 4:27:57 PM com.hazelcast.nio.ConnectionManager
INFO: [10.23.43.13]:5701 [CERT] 54106 accepted socket connection from /10.23.43.14:5701
Nov 19, 2013 4:27:57 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:27:57 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:27:58 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:27:58 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:27:59 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:27:59 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:28:00 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:28:00 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:28:01 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:28:01 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:28:02 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:28:02 PM com.hazelcast.impl.Node
INFO: [10.23.43.13]:5701 [CERT] ** setting master address to Address[10.23.43.14]:5701
Nov 19, 2013 4:28:02 PM com.hazelcast.cluster.ClusterManager
INFO: [10.23.43.13]:5701 [CERT]

Members [2] {
        Member [10.23.43.14]:5701
        Member [10.23.43.13]:5701 this
}

Nov 19, 2013 4:28:04 PM com.hazelcast.impl.LifecycleServiceImpl
INFO: [10.23.43.13]:5701 [CERT] Address[10.23.43.13]:5701 is STARTED
Nov 19, 2013 4:28:04 PM com.hazelcast.impl.management.ManagementCenterService
INFO: [10.23.43.13]:5701 [CERT] Hazelcast will connect to Management Center on address:     http://localhost:8080/mancenter/
Nov 19, 2013 4:28:04 PM com.hazelcast.config.UrlXmlConfig
INFO: Configuring Hazelcast from 'jndi:/localhost/pwc-ui/WEB-INF/classes/hazelcast.xml'.
Nov 19, 2013 4:28:04 PM com.hazelcast.web.WebFilter
INFO: sticky:true, debug: true, shutdown-on-destroy: true, map-name: my-sessions
Nov 19, 2013 4:28:05 PM org.apache.catalina.startup.HostConfig deployDescriptor

Node 2 of Group CERT (note the drop and re-add)

Nov 19, 2013 4:27:11 PM com.hazelcast.nio.Connection
INFO: [10.23.43.14]:5701 [CERT] Connection [Address[10.23.43.13]:5701] lost. Reason: java.io.IOException[Connection reset by peer]
Nov 19, 2013 4:27:11 PM com.hazelcast.nio.ReadHandler
WARNING: [10.23.43.14]:5701 [CERT] hz.pwc.IO.thread-1 Closing socket to endpoint Address[10.23.43.13]:5701, Cause:java.io.IOException: Connection reset by peer
Nov 19, 2013 4:27:12 PM com.hazelcast.nio.SocketConnector
INFO: [10.23.43.14]:5701 [CERT] Could not connect to: /10.23.43.13:5701. Reason: ConnectException[Connection refused]
Nov 19, 2013 4:27:13 PM com.hazelcast.nio.SocketConnector
INFO: [10.23.43.14]:5701 [CERT] Could not connect to: /10.23.43.13:5701. Reason: ConnectException[Connection refused]
Nov 19, 2013 4:27:14 PM com.hazelcast.nio.SocketConnector
INFO: [10.23.43.14]:5701 [CERT] Could not connect to: /10.23.43.13:5701. Reason: ConnectException[Connection refused]
Nov 19, 2013 4:27:14 PM com.hazelcast.nio.ConnectionMonitor
WARNING: [10.23.43.14]:5701 [CERT] Removing connection to endpoint Address[10.23.43.13]:5701 Cause => java.net.ConnectException {Connection refused}, Error-Count: 5
Nov 19, 2013 4:27:14 PM com.hazelcast.cluster.ClusterManager
INFO: [10.23.43.14]:5701 [CERT] Removing Address Address[10.23.43.13]:5701
Nov 19, 2013 4:27:14 PM com.hazelcast.impl.PartitionManager
INFO: [10.23.43.14]:5701 [CERT] Starting to send partition replica diffs...true
Nov 19, 2013 4:27:14 PM com.hazelcast.cluster.ClusterManager
INFO: [10.23.43.14]:5701 [CERT]

Members [1] {
        Member [10.23.43.14]:5701 this
}

Nov 19, 2013 4:27:18 PM com.hazelcast.impl.PartitionManager
INFO: [10.23.43.14]:5701 [CERT] Total 0 partition replica diffs have been processed.
Nov 19, 2013 4:27:18 PM com.hazelcast.impl.PartitionManager
INFO: [10.23.43.14]:5701 [CERT] Re-partitioning cluster data... Immediate-Tasks: 0, Scheduled-Tasks: 0
Nov 19, 2013 4:27:57 PM com.hazelcast.nio.SocketAcceptor
INFO: [10.23.43.14]:5701 [CERT] 5701 is accepting socket connection from /10.23.43.13:54106
Nov 19, 2013 4:27:57 PM com.hazelcast.nio.ConnectionManager
INFO: [10.23.43.14]:5701 [CERT] 5701 accepted socket connection from /10.23.43.13:54106
Nov 19, 2013 4:27:57 PM com.hazelcast.web.WebFilter
INFO: Created new session with id: HZ650FDF62693F45A99AC0C30BBD8840B0
Nov 19, 2013 4:27:57 PM com.hazelcast.web.WebFilter
INFO: 195 is sessions.size and originalSessions.size: 195
Nov 19, 2013 4:27:57 PM com.hazelcast.web.WebFilter
INFO: PUTTING SESSION HZ650FDF62693F45A99AC0C30BBD8840B0
Nov 19, 2013 4:28:02 PM com.hazelcast.cluster.ClusterManager
INFO: [10.23.43.14]:5701 [CERT]

Members [2] {
        Member [10.23.43.14]:5701 this
        Member [10.23.43.13]:5701
}

Nov 19, 2013 4:28:02 PM com.hazelcast.impl.PartitionManager
INFO: [10.23.43.14]:5701 [CERT] Re-partitioning cluster data... Immediate-Tasks: 271, Scheduled-Tasks: 0
Nov 19, 2013 4:28:24 PM com.hazelcast.web.WebFilter
INFO: Created new session with id: HZAD50E5F483CC448C9FA7CB66D65848BB
Nov 19, 2013 4:28:24 PM com.hazelcast.web.WebFilter
INFO: 196 is sessions.size and originalSessions.size: 196
Nov 19, 2013 4:28:24 PM com.hazelcast.web.WebFilter
INFO: PUTTING SESSION HZAD50E5F483CC448C9FA7CB66D65848BB
Nov 19, 2013 4:28:24 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
Nov 19, 2013 4:28:24 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
Nov 19, 2013 4:28:24 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
Nov 19, 2013 4:28:24 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
Nov 19, 2013 4:28:50 PM com.hazelcast.web.WebFilter
INFO: Created new session with id: HZC9553A4C330044CA8A0C20549EE23BF0
Nov 19, 2013 4:28:50 PM com.hazelcast.web.WebFilter
INFO: 197 is sessions.size and originalSessions.size: 197
Nov 19, 2013 4:28:50 PM com.hazelcast.web.WebFilter
INFO: PUTTING SESSION HZC9553A4C330044CA8A0C20549EE23BF0
Nov 19, 2013 4:28:50 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
Nov 19, 2013 4:28:50 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
Nov 19, 2013 4:28:50 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
Nov 19, 2013 4:28:50 PM com.hazelcast.web.WebFilter
INFO: Request is instance of RequestWrapper! Continue...
10069.275: [GC [PSYoungGen: 693173K->3458K(695488K)] 877908K->188718K(2093632K), 0.0224650 secs] [Times: user=0.04 sys=0.00, real=0.02 secs]
Nov 19, 2013 4:29:18 PM com.hazelcast.web.WebFilter
INFO: Created new session with id: HZE46365454C2C45F98A7947AC40E404BB
Nov 19, 2013 4:29:18 PM com.hazelcast.web.WebFilter
INFO: 198 is sessions.size and originalSessions.size: 198
Nov 19, 2013 4:29:18 PM com.hazelcast.web.WebFilter
INFO: PUTTING SESSION HZE46365454C2C45F98A7947AC40E404BB

Solution 2

The following only works with Hazelcast 3.2-SNAPSHOT.

Lets start with the single HazelcastInstance that is shared between session replication and the application. You can do it like this:

public class HazelcastInstanceLoader {

    private final static ILogger logger = Logger.getLogger(HazelcastInstanceLoader.class);

    public static HazelcastInstance load(String instanceName) throws Exception {
        String configName = System.getProperty("hazelcast.config");
        if (configName == null) {
            configName = "hazelcast.xml";
        }

        Config config;
        if (configName.startsWith("file:")) {
            String filename = configName.substring("file:".length());
            logger.info("Using hazelcast configuration file: " + filename);
            config = new FileSystemXmlConfig(filename);
        } else {
            logger.info("Using hazelcast classpath resource: " + configName);
            config = new ClasspathXmlConfig(configName);
        }
        config.setInstanceName(instanceName);
        return Hazelcast.getOrCreateHazelcastInstance(config);
    }
}

And now the Spring configuration:

<bean id="hazelcastInstance"
      class="org.springframework.beans.factory.config.MethodInvokingFactoryBean">
    <property name="staticMethod" value="com.hazelcast.webmonitor.HazelcastInstanceLoader.load"/>
    <property name="arguments">
        <list>
            <value>default</value>
        </list>
    </property>
</bean>

So when this is loaded, we have a named HazelcastInstance 'default'.

When I configure the session replication like this:

<filter>
    <filter-name>hazelcast-filter</filter-name>
    <filter-class>com.hazelcast.web.WebFilter</filter-class>
    <init-param>
        <param-name>instance-name</param-name>
        <param-value>default</param-value>
    </init-param>
</filter>

Then the session filter will try to load the hazelcastinstance with that name. Since the 'default' HazelcastInstance already is created because the Spring applicationcontext is loaded, the session filter will use that instance and not create a new one.

If you need to have fully seperate configuration files, just specify a file using the 'hazelcast.conf' system property (see the code of the HazelcastInstanceLoader). Instead of relying on a system property, you could also modify the HazelcastInstanceLoader.load method to accept a 'path' property, which you can inject from Spring.

Setting different groups for different environments is a useful way to make sure that machines in these environments, don't form a group. But if you want to share configuration, and only on the details there are differences (e.g. groupnames), then you can also make use of variables in the xml:

<hazelcast>
    <group>
       <name>${groupname}</name>
       <password>${password}</password>
    </group>
    ...
 </hazelcast>

Does this answer your question?

16,228

Author by

user1250852

Updated on June 14, 2022

Comments

user1250852 almost 2 years
I need to set up Hazelcast session caching using Spring. Using the configuration from the hazelcast docs is simple. However, its insufficient. I need to use a different configuration file for each one of my environments (DEV, QA, PROD). Alternatively (Ideally), I would like to use several properties from a spring bean that would be set during the initialization of the spring container. According to the hazelcast documentation, all I need to do set a group for each of my environments. like so:
```
<hazelcast>
    <group>
       <name>dev</name>
       <password>dev-pass</password>
   </group>
   ...
</hazelcast>
```
As a bonus, I would like the cache to be a single cache used for both sessions and application level objects (Maps, Queues, etc).

Could anyone share an example on how they would do this? Thank you for your help.
user1250852 over 10 years

I'm not sure if it does. I think I have it working like this: 1) I believe the web-filter creates the hazelcast instance first using an instance name from the init-parameter insdie the web.xml. The instance name is "CACHE". 2) Then, Using Spring's PropertyPlaceholderConfigurer I read in a bunch of properties from a property file and modify the same instance except this time i'm assigning a group name (i.e. LOCAL, DEV, CERT, PROD). From the logs, It seems to modifying the 1 instance. I've also verified that it is indeed caching the session. Does this seem wrong?
pveentjer over 10 years

I think will create 2 different cluster members and not a single shared instance between your app and session. Can you provide some logging, I'm especially in parts like this: INFO: [172.18.1.102]:5701 [dev] Members [2] { Member [172.18.1.102]:5701 this Member [172.18.1.102]:5702 } edit Grr.. the layout is messed up.
pveentjer over 10 years

If that works for you than I would go for it. We are using the approach I suggested within Hazelcast management center. So you can use it is you want.
user1250852 over 10 years

Thank you @pventjer. I guess I was hoping if you could tell me if my approach was wrong or not.
user1250852 over 10 years

@pveentjer, I think you are right. Let me investigate this some more.
pveentjer over 10 years

Ok. I hope you are going to post your findings soon :)
pveentjer over 10 years

Do you have an update, so that future questions can be resolved by your question as well? I think (I'm 99.9999% sure) that with your solution, multiple Hazelcast instances are created. My solution makes use of the Hazelcast.getOrCreateHazelcastInstance method I added to prevent duplicate instances from being created.
user1250852 over 10 years

@pveentjer. See above. Note I have a slightly modified version of hazelcast.xml. Let me know what you think. Thanks!
pveentjer over 10 years

I think what happens is that multiple hazelcast instances are being created. Can you show us some of the logging where the cluster is formed?
pveentjer over 10 years

I see you have a 2 node cluster, but they have different ip addresses, so apparently you are not suffering from the 2 hazelcast instances on a single machine (1 for session + 1 for application). That is good to hear. But to me it is unclear how this is done. I added a method specially in hazelcast: Hazelcast.getOrCreateHazelcastInstance especially to have an atomic get or create operation that prevents this issue. Also the session filter I changed so that is has a parameter 'name' to be used in this method. So I'm curious how you did this.