Saturday, February 20, 2010

8. Explain Silent Mode of installation in websphere 6.1?
Ans. We have to check or change the options which are given bellow… (for instance given example will work on Linux).
1. silentInstallLicenseAcceptance="true"
2. installType="installNew"
3. feature="samplesSelected"
4. installLocation="/opt/IBM/WebSphere/AppServer"
5. profileType="cell"
6.PROF_enableAdminSecurity="true"
7. PROF_adminUserName="admin"
8. PROF_adminPassword="admin"
9. PROF_samplesPassword="samples"
10. PROF_dmgrProfileName="Dmgr01"
11. PROF_appServerProfileName="AppSrv01"
12. PROF_enableService="true"
13.PROF_serviceUserName="root"
14. PROF_dmgrHost="localhost"
15. PROF_dmgrPort="8879"
16. PROF_dmgrAdminUserName="wasadmin"
17. PROF_dmgrAdminPassword="wasadmin"
18. traceFormat='text'
19. traceLevel='INFO'
  1. If the installation fails, what are the probable reasons? Where do I check?

    a. Confirm the installation failed by finding “INSTCONFFAILED” and EXITCODE=1 messages in /logs/install/install.log file.
    b. If you were enable trace you can find same messages and more info from /logs/install/trace.txt.
    c. Check the command prompt from which the installation panel was launched for error messages.
    d. Look up any error or warning messages in the message reference table by selecting the ″Reference″ view in the information center navigation and expanding the ″Messages″ heading.
    e. Check the profiles logs to find out error messages and proceed according to them
    f. Missing prerequisites
    g. Incorrect response file configuration during a silent install
    h. Errors due to limitations in non-root installations

Q17) What are the differences between Base(Express) and ND(XD)?

Q17) What are the differences between Base,Express and ND(or XD)?
Ans. Base edition and Express editions are almost similar except packaging structure. XD has advanced capabilities to ND to serve and dealing the complexity of huge applications. The differences between Base and ND edition are below
  • Performance wise no difference between Base and Network deployment


Base edition:
1) For small scale applications
2) Cell configuration, Dmgr and Node agent not available
3) It is not supporting the horizontal clustering though we can’t avoid single point of failure.

Net Work Deployment:

  1. More complex and used for large applications
  2. Cell configuartion,Deployement manager and Node agent available
  3. support vertical and Horizonal clustering that means workload management available

Websphere Topics and aproach

WAS ND 6.1 overview
 Introduction and features in V6.1
 Relate WAS to the other IBM products
 About Editions & Versions
Architecture
 Topology of WAS Base & ND
 Base edition Architecture
Linux & Virtual box
 Overview
 Virtual Box installation
 Configure Linux in Virtual Box
 Linux commands
Installation
 Installation overview
 Base edition Installation
 ND Installation
 Silent installation for ND edition
 How Verify the installation
 Probable problems During the Installation
Profile Management
 Different tools to work with a profile
 profile Directory structure
 Backing up a profile
 Restoring a profile
 How to delete a Profile
 Node federation
 profile types
System Management
 Cell, Dmgr, Node, Node Agent, Profile, Server terminology
 Start and Stop the Environment
 Admin console overview
 Synchronization process
Application Deployment
 Types of deployments
 Deploy the sample Application
 Configuration and settings of an application
 Configurations and settings of server
Configuration with External Systems
 JDBC Configuration
o Data providers
o Data sources
o J2c Authentication
 Installing and work with DB2 Database
 Deploy the JDBC Application
 WebSphere MQ Configuration
o Create the Queue and Queue manager
o Configure the Queue and Queue manager
o Install the Application to access the Queue
o Understand the application flow of execution
IBM HTTP Server & Plug-in
 IHS v6.1 overview
 Installation & verification
 Configuration & Log files
 Install plug-in
 Create web server definition
o From the directory (manual)
o From admin console
 Generate & propagate the plug-in through admin console
WSAdmin & Scripting
 Essential of WSAdmin?
 Introduction to MBeans
 WSAdmin Commands
 introduction to Jacl and Jython
Security
 overview
 Managing Users & Groups
 Enabling the Security
 Configure SSL between IHS & WAS
 creation & managing certificates
Workload Management
 Clustering (vertical & Horizontal)
 Virtual Host
 Data Replication Service (DRS)
 Planning & Architecture to achieve HA
 Edge Components
Performance Monitoring & Tuning
 Enable Application Server Performance monitoring
 Dynamic Cache
 Tivoli Performance Viewer (TPV)
 Request Metrics
Problem Determination & troubleshooting
 Logs and trace
 Heap dump & Thread dump
 Hung Thread detection
 Memory leaks diagnostics
 How to send error to IBM
Product updates
 Installing the fix pack
 WAS Best Practices
Interview & Certification stuff
 Sample resumes
 WAS Interview Questions
 Certification Dumps
 Redbooks and other Resources

Friday, February 19, 2010

Websphere interview Questions 3?

Q16) Websphere interview Questions 3?

41. Is the node Agent will create during the node federation?
42. What will happened when you federate a node to Dmgr explain completely?
43. What is the log file for node federation?
44. How do you synchronize changes node level server – cell configuration (Master configuration)?
45. How do you disable auto synchronization from admin console?
46. What is the difference between Configurator/ monitor/ Operator?
47. What will happen when you run synchNode.sh? What are the precautions to run it?
48. If Dmgr having latest files than server files then what will happen when you run synchNode.sh?
49. How do you start your environment? What is the hierarchy
50. What are log files will update, when you start Dmgr/ node Agent/ server
51. What are log files will update, when you stop Dmgr/ node Agent/ server
52. If you give wrong credentials when you start server / node Agent/ Dmgr, then process will start?
53. If you give wrong credentials when you stop server / node Agent/ Dmgr, then process will stop?
54. How do you check the server status?
55. How do you check the node agent / Dmgr status or all servers at node level?
56. How do you restore the profile?
57. Explain it through both restoreConfig.sh?
58. Tell me the command to restore a profile by using manageprofiles.sh?
59. If restoring profile fails then what to do?
60. What is the log file for restore a profile and where it is?

websphere intervew question 2.

Q15)websphere intervew question 2.

31. How do you take the backup?
32. What is the profile backup policy in your company?
33. List various tools to take the backup?
34. Explain it through BackupConfig.sh?
35. Explain by using manageprofiles.sh? (or) What is the command to take the backup?
36. Could you take the backup without stopping the servers?
37. If so explain how it would be?
38. What is the log file responsible for backup a profile and where it would located?
39. What is the tool available to convert unmanaged node to managed node?
40. What is the syntax for addNode.sh?

Websphere Interview Questions?

1. What are different editions available in WAS?
2. What are the differences between Base/Express and ND/XD?
3. How many Types of Profiles are available?
4. What is the difference between Managed node and an unmanaged node?
5. Explain the procedure to install WAS ND
6. How many Modes are available to install WAS?
7. Explain Silent Mode of installation?
8. What are the Steps involved in GUI mode Installation?
9. If the installation fails, what are the probable reasons? Where do I check
10. If it fails even before create an install.log file then where do I check?
11. If it fails to invoke Installation wizard, then what to do? What are the reasons? Did you face it
12. What is the difference between 5.x and 6.x?
13. What is the difference between 6.0 and 6.1?
14. Explain the scenario WAS environment migration from 5.x to 6.x?
15. What are the different type of updates are available?
16. Did you update WAS in silent mode?
17. What is meant by fix pack?
18. How do you apply a fix pack?
19. What is difference between refresh pack and fix pack?
20. What are the log files will create during applying a fix pack / refresh pack?
21. Did you involved in migration 4.x to 5.x or 6.x?
22. What is the procedure to do it?
23. What are the logs will update?
24. What is the difference between Pre Update and Post Update tools / Logs?
25. How many types profile creation are existed?
26. How you create a profile?
27. Explain the steps involved in profile creation (GUI)?
28. What is the Command to create a profile through terminal/command prompt?
29. Where do I find bootstrap port number of particular node?
30. “About this profile.txt” is meant for what?

Q13) How do you check java processes currently running?

Q13) How do you check java processes currently running?
ps –ef grep java

Thursday, February 18, 2010

What is clustering? Advantages?

What is clustering? Advantages?
Sol:
A configuration that may provide better performance with multiple processors
You will notice in this graphic a cluster (or group of server processes) residing on the same physical machine.
Vertical scaling is defining multiple members of the same cluster on the same physical machine. Other components such as the Web server and deployment manager can be on the same machine or on separate machines. Vertical scaling is appropriate in environments with large, under-used machines.
A single Application Server runs in a single JVM process, and cannot always fully utilize the CPU power of a large machine and drive the load up to 85 - 100%. This is particularly true on large multiprocessor machines, because of inherent concurrency limitations within a single Java Virtual Machine (JVM). Vertical scaling provides a straightforward mechanism to create multiple JVM processes, which together can fully utilize all the processing power available.
How does horizontal scaling differ from vertical scaling?

Q12) About log files in WebSphere Application Server?

Q12) About log files in WebSphere Application Server?

SystemOut.log - standard JVM output log
· Indicates if the code running on the Application Server started and stopped successfully.
· Destination and name are configurable.
· Can be used for user messages.
· SystemErr.log - standard JVM error log
· Identifies exceptions thrown by the code running on the Application Server.
· Destination and name are configurable.
· startServer.log and stopServer.log
· Describes the startup and shutdown of the Application Servers.
· activity.log: events that show a history of activities
· Use Log Analyzer to read output from this file.
· Located at: \logs
· http_plugin.log - plug-in trace log
· Errors and data from the Web server plug-in.
· trace.log - output from diagnostic trace.

Q11) Session Persistence in websphere:

Q11) Session Persistence in websphere:

1. Session object cached in memory by server.
2. Session object will be lost if server fails.
3. Two methods to enable persistence and overcome this problem.
· Database.
· Session objects persisted using JDBC data source.
4. DB2 included in WebSphere Application Server package for session persistence.
5. Memory-to-Memory replication.
6. Sessions copied to another server using WebSphere Internal Messaging.
7. Multiple topology models possible:
· Single Replica
· N-way peer-to-peer
· Client/server (Dedicated replication server)
· Can specify when replication performed
· Data transfer between JVMs can be encrypted
· Better performance than database persistence
To support failover, a mechanism is required that enables another server to access the session object if the primary server handling the session fails. WebSphere Application Server V5 supports two methods of persistence:
Database - a database can be configured for session persistence. You can define a JDBC provider and data source and configure this for session persistence in the session manager configuration. Various options are provided to balance performance and recovery in this configuration. Database access is relatively slow, and could slow down activities, but caching helps ease that problem by reducing the number of reads to the database.
Memory to Memory replication is a process whereby in-memory session data can be copied over to another server’s memory. Memory-to-memory replication can use one of three basic topologies - Single replica, peer-to-peer, and client/server. Each has advantages depending on the scenario. When to persist is also configurable - at the end of each request, at a timer interval, or when directed by the application code - which is to say, when the synch() method is called. Memory to memory session replication has all the features that database persistence has (except the database-specific options, like row size) and the traffic can be encrypted. It is available in WebSphere Application Server Network Deployment and editions above this. Session persistence to memory has some performance advantages over database persistence, and scales well

Q10) How to resolve the Unable to stop a server process:

Q10) How to resolve the Unable to stop a server process:

You are trying to stop an application server through the administrative console but are getting failure messages.
Figure shows the result that you would see in the administrative console if you tried to stop an application server that had hung. It takes some time for the stop request to time out.
In this case, the SystemOut.log for the deployment manager will most likely not contain any relevant messages. However, in the SystemOut.log for the node agent, you might see messages similar to those that are shown in Example Node agent error stopping an application server [7/11/05 13:51:54:207 EDT] 0000000d ThreadMonitor W WSVR0605W: Thread "SoapConnectorThreadPool : 6" (00000032) has been active for 607027 milliseconds and may be
hung. There is/are 1 thread(s) in total in the server that may be hung.

In this example, the problem is that the application server is hung and cannot respond to requests. You might also see a situation in which the node agent is
hung, In the case where the node agent is hung, the administrative console will eventually time out after at least 10 minutes. You will see a message in the
deployment manager’s SystemOut.log before the time out. If an application server is hung, you can stop it by killing the Java process
Q8) webshphere - Root causes for HTTP 404 errors:

Based on symptoms that customers report, we can usually narrow the problem down to one of two types:
1) Page cannot be displayed or JSP/JSF error
2) WebGroup/virtual host not defined

STEP 1. Page cannot be displayed or JSP/JSF error
When we have a “Page cannot be displayed” error and the resource is a JSP page, JSF page, or servlet, or the browser is displaying a JSP error, initiate the following actions:
a. Verify that the Web server plug-in is working correctly
b. Verify that the URL that is causing the error is specified correctly
c. Verify that the Web server is responding
d. Verify that the application is running
If in case Step 1 provided hasn’t solve the problem then check the Step 2

STEP 2: WebGroup/virtual host not defined
For a “WebGroup/virtual host not defined” error, take the following actions:
a. Verify that the virtual host configuration is correct
b. Verify that the URL causing the error is specified correctly
c. Verify that the application is running
HTTP 404 errors in websphere:

HTTP 404 errors can have different underlying causes. Some examples of these causes are:
Ø External factors, such as a problem in the Web server
Ø Configuration problems, such as an incorrect Web server plug-in or virtual host configuration
Ø Runtime problems, such as an application or application server not started
Ø User or application problems, such as an incorrectly specified URL

The first thing to check is the integrity of the following system components:

1) Web server à Resolve Web server problems
2) Application server àVerify that App srvr is started
3) Application à Verify that App is started

If these are all working properly or you are not sure which application and server are involved, collecting more information like: Error messages, Logs and try to analyze them.
Ø Errors displayed by the user browser, including the URL that failed
Ø SystemOut log data for the app server
Ø If application is deployed to a cluster, you might need to collect the logs from each active server in the cluster
Ø Web server access and error logs
Q7) How to configure JDBC and datasource in websphere

Configuration:
àAdminConsoleàResourcesàJDBCprovidersà
àSelect the scope (cell level or node level)
àclick new
àselect the Database type (Sybase,oracle,etc)
à select the provider type (oracle jbdc driver)
à select the implementation type (connection pool)
àclick on the driver
àselect the DataSource
àClick on new
àgive a name to the datasource
àoracleDatasourceProperties(URL:jdbc:oracle:thin:@192.168.1.14:1521:XE)
àclick on J2EE Connector Architecture (J2C) authentication data entries
àGive username and password and
àgive the component-managed authentication aliases
àand set the environment variable
àgo to Environmentàwebsphere variablesàclick on the level-àclick on
newàOracle_jdbc_driver_path and give the address of the 14.jar
-àTest the connection
Q6) What is virtual host?
A virtual host is a configuration enabling a single host machine to resemble multiple host machines. It consists of a host alias or aliases, which consist of a host name and a port number. If you specify an asterisk (*) as a host name, all host names and IP addresses that the Web server can receive will be mapped to that virtual host.
There are two virtual hosts defined during installation, default_host and admin_host.
· The default_host virtual host is intended for access to user applications, either through the HTTP transport or through a Web server. At installation time, it is configured as the default virtual host for the server1 application server. It is configured to match requests to ports 80, 9080, and 9443 for any host name.
· The admin_host virtual host is used for access to the WebSphere administrative console. It is configured to match requests to the secure ports 9090 (HTTP transport) and 9043 (Web server) for any host name. When you install an application, you associate a virtual host with each Web module in the application. By associating a virtual host with a Web module, requests that match the host aliases for the virtual host should be processed by servlets/JSPs in this Web module. The Web server plug-in also checks the URI of the request against the URIs for the Web module to determine whether the Web module can handle them or not.

A single virtual host can be associated with multiple Web modules unless each application has unique URIs. If there are same URIs among applications, different virtual hosts must be created and associated with each of the applications.
Q5) Detecting hung threads in J2EE applications
A common error in J2EE applications is a hung thread. A hung thread can result from a simple software defect (such as an infinite loop) or a more complex cause (for example, a resource deadlock). System resources, such as CPU time, might be consumed by this hung transaction when threads run unbounded code paths, such as when the code is running in an infinite loop. Alternately, a system can become unresponsive even though all resources are idle, as in a deadlock scenario. Unless an end user or a monitoring tool reports the problem, the system may remain in this degraded state indefinitely.
The hang detection option for WebSphere Application Server is turned on by default. You can configure a hang detection policy to accommodate your applications and environment so that potential hangs can be reported, providing earlier detection of failing servers. When a hung thread is detected, WebSphere Application Server notifies you so that you can troubleshoot the problem.
Using the hang detection policy, you can specify a time that is too long for a unit of work to complete. The thread monitor checks all managed threads in the system (for example, Web container threads and object request broker (ORB) threads) . Unmanaged threads, which are threads created by applications, are not monitored.
When WebSphere Application Server detects that a thread has been active longer than the time defined by the thread monitor threshold, the application server takes the following actions:
Logs a warning in the WebSphere Application Server System.Out log file that indicates the name of the thread that is hung and how long it has already been active. The following message is written to the log: WSVR0605W: Thread threadname has been active for hangtime and may be hung. There are totalthreads threads in total in the server that may be hung.
where: threadname is the name that appears in a JVM thread dump, hangtime gives an approximation of how long the thread has been active and totalthreads gives an overall assessment of the system threads.
Issues a Java Management Extensions (JMX) notification. This notification enables third-party tools to catch the event and take appropriate action, such as triggering a JVM thread dump of the server, or issuing an electronic page or e-mail. The following JMX notification events are defined in the com.ibm.websphere.management.NotificationConstants class:
TYPE_THREAD_MONITOR_THREAD_HUNG: This event is triggered by the detection of a (potentially) hung thread.
TYPE_THREAD_MONITOR_THREAD_CLEAR: This event is triggered if a thread that was previously reported as hung completes its work.
Triggers changes in the performance monitoring infrastructure (PMI) data counters. These PMI data counters are used by various tools, such as the Tivoli Performance Viewer, to provide a performance analysis.
False Alarms
If the work actually completes, a second set of messages, notifications and PMI events is produced to identify the false alarm. The following message is written to the System.out log: WSVR0606W: Thread threadname was previously reported to be hung but has completed. It was active for approximately hangtime. There are totalthreads threads in total in the server that still may be hung.
where threadname is the name that appears in a JVM thread dump, hangtime gives an approximation of how long the thread has been active and totalthreads gives an overall assessment of the system threads.
Automatic adjustment of the hang time threshold
If the thread monitor determines that too many false alarms are issued (determined by the number of pairs of hang and clear messages), it can automatically adjust the threshold. When this adjustment occurs, the following message is written to the System.out log: WSVR0607W: Too many thread hangs have been falsely reported. The hang threshold is now being set to thresholdtime.
where: thresholdtime is the time (in seconds) in which a thread can be active before it is considered hung.
You can prevent WebSphere Application Server from automatically adjusting the hang time threshold.
Q4) What is a deployment descriptor?

A deployment descriptor (DD) refers to a configuration file for an artifact that is deployed to some container/engine.
In the Java Platform, Enterprise Edition, a deployment descriptor describes how a web application or enterprise application should be deployed. It directs a deployment tool to deploy a module or application with specific container options, security settings and describes specific configuration requirements. XML is used for the syntax of these deployment descriptor files.
For web applications, the deployment descriptor must be called web.xml and must reside in a WEB-INF subdirectory at the web application root.
For Java EE applications, the deployment descriptor must be named application.xml and must be placed directly in the META-INF directory at the top level of the application .ear file.
Q3)How to change administrative console session timeout
Here is the procedure:
Through Unix box:
Edit the /systemApps/adminconsole.ear/deployment.xml file in a text editor.
Locate the xml statement, as shown below:
maxInMemorySessionCount="1000" allowOverflow="true"
writeFrequency="TIME_BASED_WRITE" writeInterval="10"
writeContents="ONLY_UPDATED_ATTRIBUTES" invalidationTimeout="30">
b. Change the invalidationTimeout value to the desired session timeout and save the file.
2. Restart the console.
Through Admin console:
Go to: Server -> Application Server -> Your Server -> Web Container -> Session Management
In Session time out section of the window, you can select No time-out or Set time-out by clicking the appropriate radio button. If you choose to set the time-out, type the desired value in minutes in the box.
Q) How to setup log file rotation from admin console
Here is procedure Application servers > xyzserver > Process Definition > Logging and Tracing > JVM LogsFile Name: ${SERVER_LOG_ROOT}/SystemOut.logFile Formatting Basic (Compatible) Advanced Log File Rotation File Size -> check boxeMaximum Size ->10 MBTime -> check boxe 24 Start Time ->24 Repeat Time ->24 hours Maximum Number of Historical Log Files. Number in range 1 through 50. 2

Q) Order of Start and Stop the Servers?

Q) Order of Start and Stop the Servers?
Stop the Server’s:
1. Stop the Application Server (1st)
2. Stop the Node Agent (2nd)
3. Stop the DMGR (3rd)

Start the Server’s:
1. Start DMGR (1st)
2. Start the Node Agent (2nd)
3. Start the Application Server (3rd)