Tag: Jboss AS7

How to achieve high availability on Openshift ?

Hi,

High availability is a very important feature for any kind of infrastructure. As the name suggests the services should be available at any given point of time. You can have several parallel instance of an application and can scale up and down depending on the business requirement, without worrying much about the cost. Load is distributed across different servers, and even if one or more of the servers fails, the application is still accessible via the other application instances. HA is crucial for scalable enterprise applications, as you can improve performance by adding more gears (which will be replica of your current one).

Lets create a scaled application and see how High Availability works in Openshift. Follow Below steps :

Step-1: Create a new application. Please note that we are using “-s” here to enable scaling:

$ rhc app create -a myhaproxy -t jbossas-7 -s

Above will create a directory “myhaproxy” at the location from where you ran the command from your terminal.

Now there are two types of scaling : Automatic and Manual. The command mentioned in Step-1 creates an application which is auto-scalable, i.e. the application will be scaled based on the incoming load. However you can also scale your application manually. For eg: if you are anticipating a certain amount of load, or you have limited resources (less number of gears available), or if you want to control the cost manually.

Lets see how can we scale our application manually.

Step-2 : Navigate from the directory “myhaproxy” which got created in Step-1 to :

$ cd myhaproxy/.openshift/markers/

Step-3 : Create a blank file as “disable_auto_scaling” :

$ touch disable_auto_scaling

Step-4 : Now add the changes to git repository, commit the changes and push them to Openshift server :

..

$ cd ../../

$ git add .openshift/markers/disable_auto_scaling

$ git commit -m "disabling auto-scaling"

$ git push

..

Step-3 : Once the auto-scaling is disabled, lets enable manual scaling :

Create an SSH connection to your application :

$ssh UUID@APPNAME-NAMESPACE.rhcloud.com

for eg :

ssh 123a456c09d12345b123a12345cc1234@myhaproxy-mydomain.rhcloud.com

Step-4 : Run below command to enable manual scaling :

$ add gear -a APPNAME -u UUID -n NAMESPACE

for eg :

..

add-gear -a myhaproxy -u 123a456c09d12345b123a12345cc1234 -n mydomain

..

Now manual scaling is enabled. Let’s check if High Availability works. Try to access the application using the url :

myhaproxy-mydomain.rhcloud.com, this gives the welcome page.

Now again ssh to your application using :

ssh 123a456c09d12345b123a12345cc1234@myhaproxy-mydomain.rhcloud.com

Grep for the java process and kill the process id, now our JBoss server is down. If high availability is working, the url should still work.

myhaproxy-mydomain.rhcloud.com, if this gives the welcome page, we are good :). (Preferably try from a different browser)

You can see high availability statistics from the management console, by logging in to

You can also select minimum or maximum number of gears you want to scale up to.

Regards,
Middlewaremagic Team 🙂


Client side Native Management API for monitoring JBossAS7.1.2

Hi,

JBossAS7 is one of the best application server which provides various options to control/manage/monitor the application resources using various options like jboss-cli.sh (CLI scripts) , jboss management console, JSON based monitoring & management using curl/wget, JBoss Native Management APIs …etc

Here in this article we will see how we can manage & monitor JBossAS 7.1.2 using JBoss Native Management APIs, this approach is best for the java developers, as in many production environments it is very convenient to manage the application respources based on java code. The developers wants to mmanage things using java style of programming, So for those develpers JBoss Native Management APIs is much convenient way of managing the JBoss.

More informations on this can be found in the following link: https://docs.jboss.org/author/display/AS7/The+native+management+API

The Source code for the following Demo is available in the github repository:
https://github.com/jaysensharma/MiddlewareMagicDemos/tree/master/NativeManagement_API_JBossAS712

Step1). First of all we will create a directory somewhere in our file system as “/home/jaysensharma/NativeManagement_API_JBossAS712” and then we will create a directory with name “src” inside “/home/jaysensharma/NativeManagement_API_JBossAS712”:

Step2). Now we will use the “org.jboss.as.controller.client.ModelControllerClient” API to establish connection to the JBoss Server/Controller, So create a program as “NativeManagementClient.java” inside “/home/jaysensharma/NativeManagement_API_JBossAS712/src” as following:

import java.net.UnknownHostException;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.NameCallback;
import javax.security.auth.callback.PasswordCallback;
import javax.security.sasl.RealmCallback;
import javax.security.auth.callback.UnsupportedCallbackException;

import org.jboss.as.controller.client.ModelControllerClient;
import org.jboss.as.controller.client.ModelControllerClient.Factory;
import java.net.InetAddress;
import java.io.IOException;
import org.jboss.dmr.ModelNode;
import org.jboss.dmr.Property;


public class NativeManagementClient
{
    //static String host = "10.10.10.96"; // "localhost";
    static String host = "localhost";
    static int port = 9999;
    static String password = "admin";
    static String userid = "admin123";
    static String hostControllerName="master";
    static String serverName="JayServer";
    static boolean standaloneMode=true;     //  If you are running your Servers in Domain Mode then set this to false.
    static ModelControllerClient client = null;

    public static void main (String[] args)
       {
           try {
                 createAndCheckClientConnection();
                 performOperations(client);
               }

           catch (java.io.IOException ex)
               {
                 System.out.println("nn Unable to Connect to the Host: "+host+" or Port:"+port+"tt" + ex.getMessage());
                 //ex.printStackTrace();
               }
           catch (Exception ex)
               {
                 System.out.println("nnSomeThing is Wrong: "+ex.getMessage());
                 //ex.printStackTrace();
               }

           try {
                 if (client != null ) client.close();
               }
           catch (Exception e)
               {
                 System.out.println ("Exception: " + e.getMessage());
                 e.printStackTrace();
               }
        }


    public static void createAndCheckClientConnection() throws IOException
     {
                 // NOTE: For hostname as "localhost" there is no need to pass the username & password  */
                 //client = ModelControllerClient.Factory.create(host, port, null);

                 // If you are running this program remotely then you need to pass the credentials */
                 client = createClient (InetAddress.getByName(host), port, userid, password.toCharArray(), "ManagementRealm" );
                 System.out.println("Got the client: "+client);

                 // Checking whether Client is actually connected to Controller or not by executing dummy ModelNode? */
                 ModelNode op = new ModelNode();
                 op.get("operation").set("read-resource");
                 ModelNode returnVal=client.execute(op);
                 System.out.println("nnrelease-version: " + returnVal.get("result").get("release-version").asString());
                 System.out.println("release-codename: " + returnVal.get("result").get("release-codename").asString());
     }

   public static void performOperations(ModelControllerClient client)
      {
                  if(standaloneMode==true)
                     {
                        // FOR STANDALONE MODE use the "TestStandaloneModel" class as following:
                        TestStandaloneModel testStandaloneModel=new TestStandaloneModel();

                        // Getting Web Subsystem runtime Details */
                        testStandaloneModel.getWebSubsystemRuntimeDetails(client);
                        // Testing Non XA DataSource ExampleDS */
                        testStandaloneModel.testNonXADataSource(client,"ExampleDS");
                        // Monitoring Application Statistics where application name is "Log4jDemo.war" */
                        testStandaloneModel.monitorApplicationStatistics(client,"Log4jDemo.war");
                     }
                  if(standaloneMode==false)
                    {
                        TestDomainModeModel testDomainModeModel= new TestDomainModeModel();
                        // Getting Web Subsystem runtime Details */
                        testDomainModeModel.getWebSubsystemRuntimeDetails(client,hostControllerName,serverName);
                        // Testing Non XA DataSource ExampleDS */
                        testDomainModeModel.testNonXADataSource(client,hostControllerName,serverName,"ExampleDS");
                        // Monitoring Application Statistics where application name is "Log4jDemo.war" */
                        testDomainModeModel.monitorApplicationStatistics(client,hostControllerName,serverName,"Log4jDemo.war");
                    }
      }

     static ModelControllerClient createClient (final InetAddress host, final int port, final String username, final char[] password, final String securityRealmName)
      {
         final CallbackHandler callbackHandler = new CallbackHandler() {
                 public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException
                   {
                       for (Callback current : callbacks) {
                          if (current instanceof NameCallback) {
                             NameCallback ncb = (NameCallback) current;
                             System.out.println("nttncb.setName() = "+new String(password));
                             ncb.setName(new String(password));
                            } else if (current instanceof PasswordCallback) {
                             PasswordCallback pcb = (PasswordCallback) current;
                             System.out.println("nttpcb.setPassword() = "+username);
                             pcb.setPassword(username.toCharArray());
                            } else if (current instanceof RealmCallback) {
                             RealmCallback rcb = (RealmCallback) current;
                             System.out.println("nttrcb.getDefaulttest() = "+rcb.getDefaultText());
                             rcb.setText(securityRealmName);
                            } else {
                             throw new UnsupportedCallbackException(current);
                        }
                    }
               }
             };
          return ModelControllerClient.Factory.create(host, port, callbackHandler);
       }
}

Step3). This step is for accessing JBoss informations in Standalone Mode, The most important part here we will write “TestStandaloneModel.java” program inside the “/home/jaysensharma/NativeManagement_API_JBossAS712/src” using the “org.jboss.dmr.ModelNode” and “ModelControllerClient” in order to access the “web” subsystem, deployment and “DataSource statistics” related informations as following:

import org.jboss.dmr.ModelNode;
import org.jboss.dmr.Property;
import org.jboss.as.controller.client.ModelControllerClient;

public class TestStandaloneModel
  {
   public void getWebSubsystemRuntimeDetails(ModelControllerClient client)
    {
       System.out.println("nnn************************************************");
       System.out.println("Web Subsystem Runtime Details");
       System.out.println("************************************************");
       try{
             ModelNode op = new ModelNode();
             op.get("operation").set("read-resource");
             ModelNode address = op.get("address");
             address.add("subsystem", "web");
             address.add("connector", "http");
             op.get("recursive").set(true);
             op.get("include-runtime").set(true);
             op.get("operations").set(true);

             ModelNode returnVal = client.execute(op);
             String result=returnVal.get("result").toString();
             String path="/subsystem=web/connector=http";
             if(result.equals("undefined"))
                {
                   System.out.println("ntCheck ["+path+"] ** Server may not be Running");
                }
             else
                {
                   System.out.println(returnVal.get("result").toString());
                }
          }
        catch(Exception e)
          {
             e.printStackTrace();
             System.out.println("getWebSubsystemRuntimeDetails Failed: "+e);
          }
    }


   public void testNonXADataSource(ModelControllerClient client,String dataSourceName)
    {
       System.out.println("nnn************************************************");
       System.out.println("DataSource ""+dataSourceName+"" TestResults");
       System.out.println("************************************************");

       try{
             ModelNode op = new ModelNode();
             op.get("operation").set("test-connection-in-pool");
             ModelNode address = op.get("address");
             address.add("subsystem", "datasources");
             address.add("data-source", dataSourceName);
             op.get("operations").set(true);

             ModelNode returnVal = client.execute(op);
             String result=returnVal.get("result").toString();
             String path="/subsystem=datasources/data-source="+dataSourceName;
             if(result.equals("[true]"))
                {
                   System.out.println("ntNon XA DataSource ""+dataSourceName+"" is RUNNING Successfully.");
                }
             else if(result.equals("[false]"))
                {
                   System.out.println("ntNon XA DataSource ""+dataSourceName+"" is TEST FAILED Successfully. Check PATH exist or not? ["+path+"]");
                }
             else if(result.equals("undefined"))
                {
                   System.out.println("ntDataSource ""+dataSourceName+"" might not be deployed, ["+path+"]  ** Server may not be Running"+"Please Check the DataSource ""+dataSourceName+"" name, It may be INCORRECT. ntCheck PATH exist or not? ["+path+"]");
                }
          }
        catch(Exception e)
          {
             e.printStackTrace();
             System.out.println("testNonXADataSource Failed: "+e);
          }
    }


   public void monitorApplicationStatistics(ModelControllerClient client,String applicationName)
    {
       System.out.println("nnn******************************************************");
       System.out.println("Application ""+applicationName+"" RuntimeStatistics");
       System.out.println("******************************************************");
       try{
             ModelNode op = new ModelNode();
             op.get("operation").set("read-resource");
             ModelNode address = op.get("address");
             address.add("deployment", applicationName);
             op.get("recursive").set(true);
             op.get("include-runtime").set(true);
             op.get("include-defaults").set(true);
             op.get("operations").set(true);

             ModelNode returnVal = client.execute(op);
             String result=returnVal.get("result").toString();
             String path="/deployment="+applicationName;
             if(result.equals("undefined"))
                {
                   System.out.println("ntApplication ""+applicationName+ "" might not have deployed. ** Server may not be Running. Check PATH exist or not? ["+path+"]");
                }
             else
                {
                   System.out.println("ntMonitoring ""+applicationName+ """+result);
                }
          }
        catch(Exception e)
          {
             e.printStackTrace();
             System.out.println("testNonXADataSource Failed: "+e);
          }
    }
  }

Step4). This step is for accessing JBoss informations of JBoss instances running in Domain Mode, The most important part here we will write “TestDomainModeModel.java” program inside the “/home/jaysensharma/NativeManagement_API_JBossAS712/src” using the “org.jboss.dmr.ModelNode” and “ModelControllerClient” in order to access the “web” subsystem, deployment and “DataSource statistics” related informations as following:

import org.jboss.dmr.ModelNode;
import org.jboss.dmr.Property;
import org.jboss.as.controller.client.ModelControllerClient;

public class TestDomainModeModel
  {
   public void getWebSubsystemRuntimeDetails(ModelControllerClient client,String hostControllerName,String serverName)
    {
       System.out.println("nnn************************************************");
       System.out.println("Web Subsystem Runtime Details");
       System.out.println("************************************************");
       try{
             ModelNode op = new ModelNode();
             op.get("operation").set("read-resource");
             ModelNode address = op.get("address");
             address.add("host", hostControllerName);
             address.add("server", serverName);
             address.add("subsystem", "web");
             address.add("connector", "http");
             op.get("recursive").set(true);
             op.get("include-runtime").set(true);
             op.get("operations").set(true);

             ModelNode returnVal = client.execute(op);
             String result=returnVal.get("result").toString();
             String path="/host="+hostControllerName+"/server="+serverName+"/subsystem=web/connector=http";
             if(result.equals("undefined"))
                {
                   System.out.println("ntCheck ["+path+"] ** HostController HostController or Server may not be Running");
                }
             else
                {
                   System.out.println(returnVal.get("result").toString());
                }
          }
        catch(Exception e)
          {
             e.printStackTrace();
             System.out.println("getWebSubsystemRuntimeDetails Failed: "+e);
          }
    }


   public void testNonXADataSource(ModelControllerClient client,String hostControllerName,String serverName,String dataSourceName)
    {
       System.out.println("nnn************************************************");
       System.out.println("DataSource ""+dataSourceName+"" TestResults");
       System.out.println("************************************************");

       try{
             ModelNode op = new ModelNode();
             op.get("operation").set("test-connection-in-pool");
             ModelNode address = op.get("address");
             address.add("host", hostControllerName);
             address.add("server", serverName);
             address.add("subsystem", "datasources");
             address.add("data-source", dataSourceName);
             op.get("operations").set(true);

             ModelNode returnVal = client.execute(op);
             String result=returnVal.get("result").toString();
             String path="/host="+hostControllerName+"/server="+serverName+"/subsystem=datasources/data-source="+dataSourceName;
             if(result.equals("[true]"))
                {
                   System.out.println("ntNon XA DataSource ""+dataSourceName+"" is RUNNING Successfully.");
                }
             else if(result.equals("[false]"))
                {
                   System.out.println("ntNon XA DataSource ""+dataSourceName+"" is TEST FAILED Successfully. Check PATH exist or not? ["+path+"]");
                }
             else if(result.equals("undefined"))
                {
                   System.out.println("ntDataSource ""+dataSourceName+"" might not be deployed on this ["+path+"]  ** HostController or Server may not be Running"+"Please Check the DataSource ""+dataSourceName+"" name, It may be INCORRECT. ntCheck PATH exist or not? ["+path+"]");
                }
          }
        catch(Exception e)
          {
             e.printStackTrace();
             System.out.println("testNonXADataSource Failed: "+e);
          }
    }


   public void monitorApplicationStatistics(ModelControllerClient client,String hostControllerName,String serverName,String applicationName)
    {
       System.out.println("nnn******************************************************");
       System.out.println("Application ""+applicationName+"" RuntimeStatistics");
       System.out.println("******************************************************");
       try{
             ModelNode op = new ModelNode();
             op.get("operation").set("read-resource");
             ModelNode address = op.get("address");
             address.add("host", hostControllerName);
             address.add("server", serverName);
             address.add("deployment", applicationName);
             op.get("recursive").set(true);
             op.get("include-runtime").set(true);
             op.get("include-defaults").set(true);
             op.get("operations").set(true);

             ModelNode returnVal = client.execute(op);
             String result=returnVal.get("result").toString();
             String path="/host="+hostControllerName+"/server="+serverName+"/deployment="+applicationName;
             if(result.equals("undefined"))
                {
                   System.out.println("ntApplication ""+applicationName+ "" might not have deployed on this host="+hostControllerName+"/server="+serverName+"  ** HostController or Server may not be Running. Check PATH exist or not? ["+path+"]");
                }
             else
                {
                   System.out.println("ntMonitoring ""+applicationName+ """+result);
                }
          }
        catch(Exception e)
          {
             e.printStackTrace();
             System.out.println("testNonXADataSource Failed: "+e);
          }
    }
  }

Step5). Now the most important part of building & running the Native Management API client which we created, so in order to achieve that we will create a simple ant build script, So Create a “build.xml” file inside the “/home/jaysensharma/NativeManagement_API_JBossAS712” directory as following:

<project name="JBossAS712NativeManagementClient" default="all">
<property name="jboss.home" value="/home/jaysensharma/jboss-as-7.1.2.Final" />
<property name="jboss.module.dir" value="${jboss.home}/modules" />
<property name="basedir" value="." />
<property name="tmp.dir" value="tmp" />
<property name="src.dir" value="src" />
<property name="output.dir" value="build" />
<property name="client.jar.name" value="jbossModelAPIClient.jar" />

        <!-- Following 5 Jars are needed for Client. Client Needs the following Jar to be present in the CLASSPATH including -->
        <path id="jboss.client.classpath">
           <fileset dir="${jboss.module.dir}/org/jboss/as/controller-client/main">
               <include name="jboss-as-controller-client*.jar"/>
           </fileset>
           <fileset dir="${jboss.module.dir}/org/jboss/threads/main">
               <include name="jboss-threads*.jar"/>
           </fileset>
           <fileset dir="${jboss.module.dir}/org/jboss/as/protocol/main">
               <include name="jboss-as-protocol*.jar"/>
           </fileset>

           <fileset dir="${jboss.module.dir}/org/jboss/dmr/main">
               <include name="jboss-dmr*.jar"/>
           </fileset>
           <fileset dir="${jboss.home}/bin/client" >
               <include name="jboss-client.jar" />
           </fileset>
        </path>

        <target name="all" depends="run" />

        <target name="run">
           <delete dir="${tmp.dir}" />
           <mkdir dir="${tmp.dir}" />
           <delete dir="${output.dir}" />
           <mkdir dir="${output.dir}" />
           <javac srcdir="${src.dir}" destdir="${tmp.dir}"  includes="NativeManagementClient.java,TestStandaloneModel.java,TestDomainModeModel.java" classpathref="jboss.client.classpath"/>
           <jar jarfile="${output.dir}/${client.jar.name}" basedir="${tmp.dir}" compress="true" />
           <delete dir="${tmp.dir}"/>
           <java classname="NativeManagementClient" fork="true">
               <classpath>
                  <pathelement location="${output.dir}/${client.jar.name}"/>
                  <path refid="jboss.client.classpath"/>
               </classpath>
           </java>
        </target>

</project>

NOTE: The only change in the above file you need to do is to change the “jboss.home” directory path in the second line of the above script to point to your own JBoss AS7 directory. It requires 5 Jars to be present in the Client’s classpath as mentioned in the above xml file.

Step-6). Now before running your ANT script to build and deploy the above webapplication you should have the ANT as well as JAVA set in the $PATH variable of the Shell / command prompt as following:

For Unix Based OS:
export PATH=/home/jaysensharma/jdk1.6.0_21/bin:/home/jaysensharma/org.apache.ant_1.6.5/bin:$PATH

For Windows Based OS:
set PATH=C:/jdk1.6.0_21/bin;C:/org.apache.ant_1.6.5/bin;%PATH%

Step-7). Now once the PATH is set In the command/Shell prompt you can move inside the directory “/home/jaysensharma/NativeManagement_API_JBossAS712” and then run the ant to build and deploy the EJB based EAR applicationon your JBoss Standalone full profile, by running the command “ant deploy”

[jsenshar@localhost NativeManagement_API_JBossAS712]$ ant
Buildfile: build.xml

run:
    [mkdir] Created dir: /home/jaysensharma/NativeManagement_API_JBossAS712/tmp
   [delete] Deleting directory /home/jaysensharma/NativeManagement_API_JBossAS712/build
    [mkdir] Created dir: /home/jaysensharma/NativeManagement_API_JBossAS712/build
    [javac] Compiling 3 source files to /home/jaysensharma/NativeManagement_API_JBossAS712/tmp
      [jar] Building jar: /home/jaysensharma/NativeManagement_API_JBossAS712/build/jbossModelAPIClient.jar
   [delete] Deleting directory /home/jaysensharma/NativeManagement_API_JBossAS712/tmp
      Got the client: org.jboss.as.controller.client.impl.RemotingModelControllerClient@7f971afc
      Nov 27, 2012 12:06:02 AM org.xnio.Xnio <clinit>
      INFO: XNIO Version 3.0.4.GA-redhat-1
      Nov 27, 2012 12:06:02 AM org.xnio.nio.NioXnio <clinit>
      INFO: XNIO NIO Implementation Version 3.0.4.GA-redhat-1
      Nov 27, 2012 12:06:02 AM org.jboss.remoting3.EndpointImpl <clinit>
      INFO: JBoss Remoting version 3.2.8.GA-redhat-1
     
     
      release-version: 7.1.2.Final-redhat-1
      release-codename: Steropes
     
     
     
      ************************************************
      Web Subsystem Runtime Details
      ************************************************
      {
          "bytesReceived" => "0",
          "bytesSent" => "0",
          "enable-lookups" => false,
          "enabled" => true,
          "errorCount" => "0",
          "executor" => undefined,
          "max-connections" => undefined,
          "max-post-size" => 2097152,
          "max-save-post-size" => 4096,
          "maxTime" => "0",
          "name" => "http",
          "processingTime" => "0",
          "protocol" => "HTTP/1.1",
          "proxy-name" => undefined,
          "proxy-port" => undefined,
          "redirect-port" => 8433,
          "requestCount" => "0",
          "scheme" => "http",
          "secure" => false,
          "socket-binding" => "http",
          "ssl" => undefined,
          "virtual-server" => undefined
      }
     
     
     
      ************************************************
      DataSource "ExampleDS" TestResults
      ************************************************
     
      	Non XA DataSource "ExampleDS" is RUNNING Successfully.
     
     
     
      ******************************************************
      Application "Log4jDemo.war" RuntimeStatistics
      ******************************************************
     
      	Monitoring "Log4jDemo.war"{
          "content" => [{
              "path" => "deployments/Log4jDemo.war",
              "relative-to" => "jboss.server.base.dir",
              "archive" => true
          }],
          "enabled" => true,
          "name" => "Log4jDemo.war",
          "persistent" => false,
          "runtime-name" => "Log4jDemo.war",
          "status" => "OK",
          "subdeployment" => undefined,
          "subsystem" => {"web" => {
              "active-sessions" => 0,
              "context-root" => "/Log4jDemo",
              "duplicated-session-ids" => 0,
              "expired-sessions" => 0,
              "max-active-sessions" => 0,
              "rejected-sessions" => 0,
              "session-avg-alive-time" => 0,
              "session-max-alive-time" => 0,
              "sessions-created" => 0,
              "virtual-host" => "default-host",
              "servlet" => {"servlets.TestServlet" => {
                  "load-time" => 0L,
                  "maxTime" => 9223372036854775807L,
                  "min-time" => 0L,
                  "processingTime" => 0L,
                  "requestCount" => 0,
                  "servlet-class" => "servlets.TestServlet",
                  "servlet-name" => "servlets.TestServlet"
              }}
          }}
      }

all:

BUILD SUCCESSFUL
Total time: 2 seconds

Step-8). If you are running your JBoss in Domain mode then you need to just edit the “NativeManagementClient.java” file, and just change the variable “standaloneMode” value to “false” as following:

static boolean standaloneMode=false;

.
.
Thanks
MiddlewareMagic Team 🙂


SAR dependency alternate approach using @Singleton in JBossAS7.1.2

Hi,

SAR files are called as Service Archives. The extension of SAR files are *.sar which contains a “META-INF/jboss-service.xml” file, this file describes the custom MBeans which has to be exposed at the time of deployment or JBoss Startup. JBoss’s service archive architecture is based on the JMX and the SAR files which are basically JBoss specific can be deployed in the jboss inorder to publish your MBean based services. At the time of JBoss startup these service archive deployer (SARDeployer) instantiates the JBoss service classes and exposes them as manageable beans through JMX.

In previous release of JBoss 5/6 the SAR provided mbeans dependency could be very easily defined using <depends> tag, as following:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE server>
<server>
    <mbean code="custom.mbean.MyServerMonitor" name="service.server.monitor:service=MyMonitor">
         <attribute name="Frequency">5000</attribute>
         <depends>jboss.jca:service=DataSourceBinding,name=MySqlDS</depends>
    </mbean>
</server>

@org.jboss.ejb3.annotation.Service and @org.jboss.ejb3.annotation.Management are no longer supported which could be used to define Services. However in JBossAS7 this approach of defining the dependency is not good and you may see following kind of exceptions at the time of server startup:

JBAS014775:    New missing/unsatisfied dependencies:
      service jboss.mbean.service."jboss.as:subsystem=datasources,data-source=MySqlDS".create (missing) dependents: [service jboss.mbean.service."service.server.monitor:service=MyMonitor".create]
      service jboss.mbean.service."jboss.as:subsystem=datasources,data-source=MySqlDS".start (missing) dependents: [service jboss.mbean.service."service.server.monitor:service=MyMonitor".start]

JBossAS7 is fully EE6 certified application server and it provides a much better approach to create a Service with the help of EJB3.1 specific “javax.ejb.Startup” and “javax.ejb.Singleton” annotations. This kind of service can be made dependent to other services like DataSource. In this example we will see What is the better approach to define a service (without using container specific SAR feature).

The Source code for this demo can be found in the following github link:
https://github.com/jaysensharma/MiddlewareMagicDemos/tree/master/SingletonServiceDemo

Creating DataSource in JBossAS7.1.2

As we are going make our Service dependent on a DataSource, sothat we can see how the dependency goes.

Configuration-1). So here first of all we will create a DataSource by running the following CLI script in batch mode. So create a file with name “createDataSource.cli” somewhere in your filesystem like “/home/jaysensharma/SingletonServiceDemo/createDataSource.cli” as following:

deploy  /home/jaysensharma/SingletonServiceDemo/mysql-connector-java-5.1.13-bin.jar

/subsystem=datasources/data-source="MySqlDS":add(jndi-name="java:jboss/datasources/MySqlDS",driver-name="mysql-connector-java-5.1.13-bin.jar",connection-url="jdbc:mysql://localhost:3306/testDB",user-name="root",password="redhat")

Configuration-2). Now start your “$JBOSS_HOME/bin/jboss-cli.sh” script in order to run the above deploy the mysql driver and create DataSource as following:

./jboss-cli.sh -c --controller=10.10.10.10:9999 --file=/home/jaysensharma/SingletonServiceDemo/createDataSource.cli

Configuration-3). As soon as you will run the cli script as mentioned above you will see that the following kind of datasource is created on your standalone*.xml.

                <datasource jndi-name="java:jboss/datasources/MySqlDS" pool-name="MySqlDS">
                    <connection-url>jdbc:mysql://localhost:3306/testDB</connection-url>
                    <driver>mysql-connector-java-5.1.13-bin.jar</driver>
                    <security>
                        <user-name>root</user-name>
                        <password>redhat</password>
                    </security>
                </datasource>

Creating @Singleton service dependent on the DataSource

Step1). First of all we will create a directory somewhere in our file system as “/home/jaysensharma/SingletonServiceDemo” and then we will create a directory with name “src” inside “/home/jaysensharma/SingletonServiceDemo”:

Step2). Now write a @Startup @Singleton EJB3.1 service using “SingletonServiceBean.java” inside “/home/jaysensharma/SingletonServiceDemo/src” as following:

package sar.dependency.alternative;
import javax.ejb.Startup;
import javax.ejb.Singleton;
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

//commons logging
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

// DataSource related
import javax.sql.DataSource;
import java.sql.Connection;

// Resource Injection related
import javax.annotation.Resource;

@Startup
@Singleton

public class SingletonServiceBean
 {
     private static Log logger = LogFactory.getLog(SingletonServiceBean.class);
     Connection con=null;


     public SingletonServiceBean()
            {
               logger.info("SingletonServiceBean constructor invoked.");
            }


     @Resource(name = "java:jboss/datasources/MySqlDS")
     DataSource ds;
     /* This @PostConstruct annotation is required to tell JBoss to invoke the "performOperations" immediately after the "SingletonServiceBean" creation. */
     @PostConstruct
     public void performOperations()
	    {
               logger.info("SingletonServiceBean performOperations() invoked.");
               try{
                     con=ds.getConnection();
                     logger.info("***** DataSource = "+ds+" . Connection con = "+con+" retrieved from the ConnectionPool.*****");
                  }
               catch(Exception e)
                 {
                     logger.error("Unable to get Connection From DataSource = "+ds+" ERROR: "+e.getMessage());
                     e.printStackTrace();
                 }
	    }


	@PreDestroy
	public void cleanUp() throws Exception {
	  logger.info("cleaning up connections.");
          if(con!=null)
            {
               try{
                     con.close();
                     logger.info("Connection con = "+con+" is successfully returned to the ConnectionPool.");
                  }
               catch(Exception e)
                 {
                     logger.error("Unable to Close Connection con = "+con+" ERROR: "+e.getMessage());
                     e.printStackTrace();
                 }
               finally{
                        try{   con.close(); }
                        catch(Exception ee) { ee.printStackTrace(); }
                      }
            }
	}
 }

Step3). Now the most important part of building / deploying the Singleton Service which we created, so in order to achieve that we will create a simple ant build script, So Create a “build.xml” file inside the “/home/jaysensharma/SingletonServiceDemo” directory as following:

<project name="SingletonStartupService" default="all">
<property name="jboss.home" value="/home/jaysensharma/jboss-as-7.1.2.Final" />
<property name="jboss.module.dir" value="${jboss.home}/modules" />
<property name="basedir" value="." />
<property name="tmp.dir" value="tmp" />
<property name="src.dir" value="src" />
<property name="output.dir" value="build" />
<property name="ear.name" value="TestSingletonService.ear" />
<property name="ejb.jar" value="singletonServiceEJB.jar" />


        <path id="jboss.classpath">
           <fileset dir="${jboss.module.dir}">
               <include name="**/*.jar"/>
           </fileset>
        </path>

        <target name="all" depends="deploy" />

        <target name="build_ear">
           <delete dir="${tmp.dir}" />
           <mkdir dir="${tmp.dir}" />
           <javac srcdir="${src.dir}" destdir="${tmp.dir}"  includes="*.java" classpathref="jboss.classpath"/>

           <jar jarfile="${tmp.dir}/${ejb.jar}" basedir="${tmp.dir}" compress="true" />

           <delete includeEmptyDirs="true">
              <fileset dir="${tmp.dir}/sar"/>
           </delete>
           <mkdir dir="${tmp.dir}/META-INF"/>
           <copy todir="${tmp.dir}/META-INF">
                <fileset dir="${src.dir}/">
                  <include name="application.xml"/>
                </fileset>
           </copy>
           <jar jarfile="${tmp.dir}/${ear.name}" basedir="${tmp.dir}" compress="true" />
           <delete includeEmptyDirs="true">
              <fileset dir="${tmp.dir}/META-INF"/>
           </delete>
           <delete file="${tmp.dir}/${ejb.jar}"/>

           <copy file="${tmp.dir}/${ear.name}" tofile="${output.dir}/${ear.name}"/>
           <delete dir="${tmp.dir}"/>
        </target>


        <target name="deploy" depends="build_ear">
            <echo message="*******************  Deploying the EAR file ${ear.name} *********************" />
            <echo message="********** ${output.dir}/${ear.name} to ${jboss.home}/standalone/deployments **********" />
            <copy todir="${jboss.home}/standalone/deployments/">
                <fileset dir="${output.dir}/">
                  <include name="${ear.name}"/>
                </fileset>
            </copy>
            <echo message="*******************  Deployed Successfully   *********************" />
        </target>

</project>

NOTE: The only change in the above file you need to do is to change the “jboss.home” directory path in the second line of the above script to point to your own JBoss AS7 directory.

Step-4). Now before running your ANT script to build and deploy the above webapplication you should have the ANT as well as JAVA set in the $PATH variable of the Shell / command prompt as following:

For Unix Based OS:
export PATH=/home/jaysensharma/jdk1.6.0_21/bin:/home/jaysensharma/org.apache.ant_1.6.5/bin:$PATH

For Windows Based OS:
set PATH=C:/jdk1.6.0_21/bin;C:/org.apache.ant_1.6.5/bin;%PATH%

Step-5). Now once the PATH is set In the command/Shell prompt you can move inside the directory “/home/jaysensharma/SingletonServiceDemo” and then run the ant to build and deploy the EJB based EAR applicationon your JBoss Standalone full profile, by running the command “ant deploy”

[jaysensharma@localhost SingletonServiceDemo]$ ant
Buildfile: build.xml

build_ear:
    [mkdir] Created dir: /home/jaysensharma/SingletonServiceDemo/tmp
    [javac] Compiling 1 source file to /home/jaysensharma/SingletonServiceDemo/tmp
      [jar] Building jar: /home/jaysensharma/SingletonServiceDemo/tmp/singletonServiceEJB.jar
    [mkdir] Created dir: /home/jaysensharma/SingletonServiceDemo/tmp/META-INF
      [jar] Building jar: /home/jaysensharma/SingletonServiceDemo/tmp/TestSingletonService.ear
   [delete] Deleting: /home/jaysensharma/SingletonServiceDemo/tmp/singletonServiceEJB.jar
     [copy] Copying 1 file to /home/jaysensharma/SingletonServiceDemo/build
   [delete] Deleting directory /home/jaysensharma/SingletonServiceDemo/tmp

deploy:
     [echo] *******************  Deploying the EAR file TestSingletonService.ear *********************
     [echo] ********** build/TestSingletonService.ear to /home/jaysensharma/jboss-as-7.1.2.Final/standalone/deployments **********
     [copy] Copying 1 file to /home/jaysensharma/jboss-as-7.1.2.Final/standalone/deployments
     [echo] *******************  Deployed Successfully   *********************

all:

BUILD SUCCESSFUL
Total time: 1 second

Step-6). As the application is deployed on your JBoss so now try restarting your JBoss and then see whether the Above service us successfully get the DataSource and JDBC Connection or not. If the Dependency is correctly working then after restarting your JBoss you will see the following kind of message on your JBoss console / logs.

22:41:51,569 INFO  [sar.dependency.alternative.SingletonServiceBean] (MSC service thread 1-1) ***** DataSource = org.jboss.jca.adapters.jdbc.WrapperDataSource@43877c42 . Connection con = org.jboss.jca.adapters.jdbc.jdk6.WrappedConnectionJDK6@5424bf0 retrieved from the ConnectionPool.*****

.
.
Thanks
MiddlewareMagic Team 🙂


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