websphere application server interview questions and answer

Thursday 25 October 2012

Technical Questions

1. Are you responsible for production support?

A) Yes

As per on call support, we have dedicate mobile and laptop every week, they will change. And Prioritize, change at every week on 24x7 basis.
2. Breifly explain about the topology of production environment?

In my production environment we are having 200 applications running across 70 RHEL boxes in 20 WebSphere cells.

Each cell has 3 nodes under dmgr, all nodes are established in horizontal cluster (different RHEL boxes), All clusters will have 3 jvms run across the RHEL boxes.

Resources: 8 onsite + 8 off shore

Role hierarchy: Business head -> IT MGR -> Middleware mgr -> off-shore team lead ->

My role is Level-1 and 2.

We are did a migration from 5.1 to 6.0/6.1, in my environment, 5.1 will be completely migrated this year end. We are using paid support from IBM 5.1(3 cells) as free support stopped by IBM.

3. Which environment you are using?

A) Soloaris 6.1/8.x , RHEL Linux: 5.1
4. How many servers and how many applications?

A) Discussed
5. which kind of applications?

A) Client Business:

1. Mortgage, 2.Trading applications
6. Applications are running on clusters?

Yes.
7. How do you verify that you are using Horizontal clusters not a vertical cluster?

A) if u have all the servers in same machine(Host) ,than its vertical ,if cluster servers are installed in different machine than its horizontal.

-OR-

Go to WAS console => select Nodes in left side => in the right side of the console you can see how many nodes make's your CELL, and also the hostname of the boxes in which the node exists.
if you see all the nodes from different hostnames then its Horizontal clustering if you see same hostname here then its Vertical clustering

8. your cluster contains how many nodes?

A) 3 nodes
9. Both nodes are running on dmgr. Dmgr is on both nodes?

A) All my production Dmgr in a single box. Nodes will be across different boxes.

Note: if in case failure of DMGR node, then how do we handle the issue?

In that case we need to wait till that problem gets resolved, for any configuration changes in the console. Generally start and stop server activities will do in application server node.
10. Is it necessary to have dmgr on both nodes?

A) NO, Single dmgr.
11. Do you have dmgr as standalone?

A) We can, but No use.
12. Can we create more than one server in standalone-environement?

A) Never worked on stand alone environment.
13. can we have more than one application in a single server?

A) many
14. I want to depoly the application in any one of the node but not cluster?

A) Node is a server
15. What kind of database you are using?

A) Oracle 10g
16. What kind of security mode you are using or JDBC connection?

A) J2C Authentication
17. What type of driver you are using? Type 4 driver

Type 1 driver: JDBC-ODBC Bridge

This driver called as JDBC-ODBC bridge.The Java Statements converts to JDBC statements.JDBC statements calls ODBC by using JDBC-ODBC bridge. ODBC drivers convert into the requirements of databases.

Java--->JDBCStat-->JDBC-ODBC bridge-->ODBC-->Databases.

Type 2 driver: Native-API/partly Java driver

This driver is called as Native Driver where it requires the some native code to connect to the databases.

Type 3 Driver: Net-protocol/all-Java driver

This driver is called as Protocal driver where

Java-->JDBC statements-->SQLStatements--> databases.

Type 4 Driver: This driver directly converts the java statements to SQl Statements which require to databases. It wont convert to JDBC statement.

18. The application should be authenticate before interacting with database?

A) It will happened, we are creating uid, pwd that will work
19. what is meant by connection pooling?

A) a connection pool is a cache of database connections maintained by the database so that the connections can be reused when the database receives future requests for data. Connection pools are used to enhance the performance of executing commands on a database. Opening and maintaining a database connection for each user, especially requests made to a dynamic database-drivenwebsite application, is costly and wastes resources. In connection pooling, after a connection is created, it is placed in the pool and it is used over again so that a new connection does not have to be established. If all the connections are being used, a new connection is made and is added to the pool. Connection pooling also cuts down on the amount of time a user must wait to establish a connection to the database.
20. what are the different methods to deploy application?

A)
21. for ear file is context root is necessary?

A) Hostname:9089/appname - context root Yes.
22. I updated the new application but the user is getting the old applicaion only?

A) need to Restart, synch
23. what are the options you have to improve performance?

A) Connection pool, Thread pool of web container, EJB container, web server parameter, jdbc connection pool

Tuning Application server

Tuning JVM, Tuning Applications, Tuning Database, Tuning JMS, Tuning security, Tuning operating systems, Tuning Web servers

Connection pool perameters:

$AdminControl getAttribute $objectname surgeCreationInterval

$AdminControl setAttribute $objectname surgeCreationInterval 30

$AdminControl getAttribute $objectname surgeThreshold

$AdminControl setAttribute $objectname surgeThreshold 15

24. to sepcify the weight of a cluster member in which file i have to modify?

A) have to modify in Plugin file
25. I am getting server 500 erro, what will be the reason?

A) Internal server error (server to db middleware)
26. How do enable GC?

In the Administrative Console, expand Servers and then click on Application Servers.

. Click on the server that is encountering the¬ "OutOfMemory" condition.

. On the Configuration tab, under Server¬ Infrastructure, expand Java and Process

Management, and click Process Definition.

. Under the Additional Properties section, click Java Virtual¬ Machine.

. Select the Verbose garbage collection check box.¬

. Click¬ Apply.

. At the top of the Administrative Client, click Save to apply changes¬ to the master

configuration.

. Stop and restart the Application Server

The verbose garbage collection output is written to either native_stderr.log or

native_stdout.log for the Application Server

verbosegc – Tells you what is being done, whether heap size is at min or max.

27. Ho to check GC is active or not, if you don't have?

A) We can check in logs.
28. can you tell me about profiles?

A) WebSphere application binary, profile sharing binaries of existing instance,
29. what is the use of virtual host?

A) Configuration that lets a single host machine resemble multiple host machines. Each virtual

host has a logical name and a list of one or more domain name system (DNS) aliases by which

it is known.
30. Is webserver & application server should be installed in a single machine or different machines?

A) We can do it, but in production different machines.

Webserver OS tuned in different way, app. server different way, normally these web servers in DMZ - Demilitarized Zone.

31. Difference between managed node and unmanaged node?

A) Managed have node agent, unmanaged not. Unmanaged node we not control from console.
32. How to check application servers are running/not?

A) Ps -grep
33. How to check WAS is running or not through PS?

A) Ps -grep

WAS Edge Components

These are the some of the WAS Edge Components.

WAS Edge Components

Caching Proxy
Proxy Server
Load Balancer
Network Dispatcher Component
Content Based Routing (CBR)
Site Selector Component

What is JDBC, Jdbc Provider and Data Source and JNDI

1. What is JDBC ?

JDBC is an API (Application Program Interfaces) , that is useful to write a java program to connect any database, and retrieve the data for the database and utilize the data in the java program.
Making a connection to a database
Creating SQL or MYSQL Statement
Execute that Sql or MySql queries in the database

We have 2 types of Jdbc drivers in WAS, Those are type 2(think) and type 4(thin/native protocol)
type 2 driver require the database client software on the client node to connect to the database server
type 4 driver connect directly to the database server

2. What is Data Source ?

Data Source allow to you to manage a pool of connection to a database
Data Source is handle to which database you want to connect , it is a communication between database and
client or end-user

3. What is Connection Pool ?

Connection pool is a place where a set of connection are kept and are used in different programs without creating connection to the database, after using the connection he can send back that connection to the connection pool

4. What is Jdbc Provider ?

It is a database provided by the vendor which database we have to use like mysql , oracle etc..
This details given by the client or vendor

5.What is JNDI ?

Java Naming Directory Interface Service is used to register the resource hosted by server's
JNDI gives unique name for every server
It is implements on the top of CORBA (Common Request Broker Architecture)

Monday 15 October 2012

Secure Soket Layer Architecture

SSL WebSphere

The SSL configuration for WebSphere provides the authentication between the WEB Server (IBM IHS 2.0.47.1) and the WebSphere JVM. The configuration uses Self Signed Certificates with a Five Year (1825 days) operational limit. No Keys are purchased to provide this security as no customer facing interaction is involved, hence certificates are self signed.

The principle sections of the setup are:-

ServerKey.jks - Holds the WebSphere Server Certificate

ServerTrust.jks - Holds the Server Key, Client Key and the Plugin Key

allowing WebSphere to trust client connections (SAS,

SOAP) and the WEB Server via the WEB Plugin.

ClientKey.jks - Holds the Client Certificate for SAS & SOAP /

WebServices Authentication.

ClientTrust.jks - Holds the Server Key and Client Key allowing the

SAS & SOAP Web Services to trust the WebSphere

JVM.

PluginKey.kdb - Holds the Plugin Certificate and the Server Key to

enable the Web Server to trust the WebSphere JVM.

PluginKey.sth - Holds the Access password for the PluginKey.kdb

Sunday 14 October 2012

IBM Hyderabad Interview Questions

Part-V : IBM Hyderabad

1)Tellme About yourself?

A) Worked as a Websphere administrator. Was responsible for deploying, configuring,

tuning, clustering, and troubleshooting WebSphere related issues.
2)Configuration of WebServer with AppServer?

A) This configuration available in httpd.conf file of a web server, in this file we will configure virtual hosts and domains etc .
3) Role of Plugin-Cfg.xml?
A) When ever request comes to Webserver it identifies the app. server configuration in this configuration file.

4) Tell me about RemoteConfiguration?
5) How do you deploy an application in AdminConsole?
6) How do you deploy an EAR file in admin console?
7) What is meant by default bindings?

A) It will bind the resources to connect….at time of startup
8)What are precompiled jsps?
9) Are you comfortable with MQ?

A) I have a little bit knowledge.
10)Tell me about MQConfiguration with WAS?

A) We will configure from console, resources -> JMS -> Queues-> integrating with MQ.
11) Tell me the command to find RAM size in AIX/Unix?
A) prtconf only for AIX

12)Command to find diskfree space?

A) Df –k or m
13) how do you provide Custom security?

A) Developer will give the authorization from an application(may be uid/pwd from Oracle DB)
14)Suppose if u enable customsecurity after opening the admin console in the rightside suppose if you got only 2 options instead of 3 then what to do?

A) question not clear
15)How much you are comfortable with scripting(JACL/JYTHON)?

A) I have little bit knowledge.

Set $

puts "About to dump threads for this jvm..."

$AdminControl invoke $jvm dumpThreads

puts "... done"

------------

Invoke the generateHeapDump operation on a JVM MBean, for example,

Finding JVM objectName:

set objectName [$AdminControl queryNames

WebSphere:type=JVM,process=<servername>,node=<nodename>,*]

Invoking the generateHeapDump operation on JVM MBean:

$AdminControl invoke $objectName generateHeapDump

Ex: wsadmin -f test.py a b c

test.py content:

import sys

first = sys.argv[0]

second = sys.argv[1]

third = sys.argv[2]

arglen = len(sys.argv)

16)In Jython script how to invoke a variable which was defined in another jython script?

Using MBeans

Calling scripts using another script

Use the execfile command to call a Jython script from another Jython script. For example:

Create a script called test1.py that contains the following:

execfile('c:/temp/script/testFunctions.py')

print printName('Cathy', 'Smith')

Create a script called testFunctions.py that contains the following:

def printName(first, last):

name = first + ' ' + last

return name

Then pass the following path as a script argument:

wsadmin -lang jython -f 'c:/temp/script/test1.py’

Wells Fargo in WAS

Part - IV : WebSphere Interview Questions

1) What are your daily day to day Activates?

A) We have ticketing tools, We have 2 Type of tickets:

1. Change request : scheduled activities like new resources creation, JVM settings, Configuration of the application and development teams raised tickets

2. Incident request : production support or monitoring like up gradation.

We have a dev team; if they found any issues they will raise a ticket.

We have a production support team, and Monitoring team, if they come across some thing abnormal then they will raise a production support tickets.

We are having WAS 5.1 and 6.1, so daily we are having configuration setups for migration, and building the similar environment as 5.1 in 6.1In different boxes as new environment.

Right now I don’t have chance to write new scripts. How to check thread dump in jacl

How do you check the health of the appserver? Is there any tool is avialable with you?
A) We have monitoring tools, at the time issue only, TPV (Tivoli Performance Viewer)/Willy Introscope, and normally it is disabled, at the time of performance issue only we will do monitoring.

2 kinds of monitoring: 1. Availability, 2. performance monitoring 24/7 or not.

L1 team using SiteScope: SiteScope WebSphere Performance Servlet Monitor to monitor the server statistics of IBM WebSphere Server (versions 3.0x, 3.5, 3.5.x, and 4.0) via a WebSphere Performance Servlet. The error and warning thresholds for the monitor can be set on as many as ten performance statistics.

3) Can u configure multpile apache webservers?

A) we can configure in httpd.conf file.
4) Is it possible to configure 10 domain names in apache? if yes? How?
A) we can use virtual hosts.

5) How do you perform heap dump and thread dump?

A) Kill -3 <>
Heap dump relate to jvm memory usage,

Thread dump relate jvm thread usage

6) Is kill -3,kill a process or create a thread dump? explain!

A) kill -3 is used create thread dump.
7) Did u work with any tools which helps you to see the heap dump or thread dump?

A) Heap dump jmap, IBM heap analyzer tool, thread dump using IBM thread analyzer /samurai

8) How to configure security and LDAP?

A) Global security,

Security availability: 1. OS security 2. LDAP (3^rd party security) 3. Custom security(Application from DB)

9) What are 202 errors?

Accepted.
10) In ls -lrt, what t stands for and r stands for l stands for?

-l shows you huge amounts of information (permissions, owners, size, and when last modified.)

-r reverses the order of how the files are displayed.

-t shows you the files in modification time
11) How to check a particular port is working or not in unix?

A) netstat -a | grep 80

Barclays Interview In Websphere

Part-III : WAS INTERVIEW QUESTION

1. What is session affinity?

A) Is nothing but a persistence.

Most servers use the term “Session Affinity” to indicate that with in a cluster of servers, requests from the same client always get routed back to same server. This eliminates the need to replicate session data like HTTP session or Stateful session Beans.

2. JVM which has been clustered, the server is in production?

A) 1. Memory to memory replication 2. Database persistence

Heartbeat mechanism work in a cluster, member of the cluster identifies that the other server is not responding it checks 3 times for every 60 seconds, if not responded then it takes the configuration using memory replication process then completes request.
3. What is fix pack?

A) Patches to fix a particular issue for a particular in environment only not other.
4. What is patch?

A) It is like independent to every body, bug fix of WAS. WAS 6.1.0.17
5. What is migration? How can you migrate from one version to another version?
A) discussed

5. How can you disable the security without admin console?

A) we can disable in Security.xml, but we can’t enable.
6. Complete configureation steps for SSL?

A) We have to install ibm http server, by using ikeyman tool we can create and use SSL certificates.
7. How to configure session management?

A) we can configure though console, either in application/deployment descriptor.
8. How can you provide security authentication for web server?

A) eTrust SiteMinder tool
9. How to know webserver version?

A) we can find in Logfile.
10. How to identify old and new context roots?

A) in Httpd.conf file we can see commented(old) and uncommented(new) data.
11. Difference between v5 & v6.

1. Multiple Profile creations with a single installation (All profiles share same WebSphere binaries)

2. Introduction of Service Integration Bus (SIB) for messaging

3. Has default JMS providers

4. Supports mixed version nodes in a v6 ND Cell

5. Has some extra add-ons in the Admin console navigation tree

6. JACL has been deprecated in 6.1

12. What is the difference between WAS and WL?

1. In weblogic u cant do clustering accros the domain,but in Websphere u can.

2. In weblogic all the configurations are stored in a single file called Config.xml ,but in Websphere its stored in a directory structure called CELL

3. In weblogic u can start the managed server without a Adminserver(using MSI-config.xml),in websphere u can not start a node with out Dmgr.

4. In websphere u can add webserver as a unmanaged node where as u cannnt do that in weblogic.
13. How many types of installation are there?

A) GUI, using Response file (silent mode), command line .
14. JACL scripting? Alredy discussed
15. If the performance, of the appliacation goes down? what will u do?

A) Performance Information should collect from monitoring tool
16. what is the difference between L1, L2, L3?

l1- is basic level (monitoring, basic configuration)

l2 -back up who are senior staff (trouble shooting)

l3 –architechts (designing / architect/ requirement(ram/box))

17. the uesr submitted the request, when that request is on processing in the middle the server crashes then what happens?

It will lost.

IBM Interview-2 Websphere Application Server

Part-II : IBM INTERVIEW QUESTIONS