Tuesday, 20 May 2014

Answers for WebSphere Application Server Interview Questions Part-1 (WebSphere Jungle)

                               Based on my knowledge i share answers.I collected some answers from many resources. If any correction,please comment it.I will modify it. Share your answers for these questions in different way. I will add those answers with your name in my blog. Help for WebSphere Beginners. 

1.What is Server?
  System that respond to requests across  network to provide a  service.This type of systems are called "Servers".
      When we use browser to request for Google page by typing URL(Uniform Resource Locator)in browser like Then request goes to Google server.Google server means it is also one system which has software and  hardware to respond requests. Then.Then we get respond from Google server.

2.What is Client?
  System that receive the response across network to get a service. This type of systems are called "Client"systems.
       We are only clients for servers. First we make request to server then we will receive the response from server.

3.What is Web Server?
    Web Servers are systems that helps to serve web content like websites.
        Normally websites are served(static pages).

4.What is Application Server?
    Application servers are systems that help to serve web content like websites.But here new terminology will come that is business logic.
    So,Application servers are systems that help to serve web content which related to business logic.
     Here everyone gets doubt.what is business logic. Actually programs are divided into 3 types(normally).1. user interface 2. business logic 3.database. Let us take one example. We are using ATM. When we reach ATM we see one system . here programmer writes logic for that system. It is  called user interface. Once we do any transaction, request will go to servers.Here comes web server and application servers. Now we assume, request comes  to application server. Here programmer writes code for receiving requests from user and responds to  the user. Application server will connect to the database and response to that user. If we want mini statement which data came from Database. It will retrieve based on your request in application server.So, logic runs under application server. But this logic can't implement under web server(some reasons only).

5.What is the need of Web Server?
     Basically static HTML pages(websites) are served fast by web server.If u don't want any logic,more security, we will go through web servers.

6.What is the need of Application Server?
     I already explained about Application server need.

7.Some examples for Web Server and  Application Server?
  web server
            Apache, IHS(IBM HTTP Server), IIS etc....
  Application Server
            IBM WebSphere Application Server, Web logic

8.What is the difference between Web Server and Application Server?
   Web server serves static content.Application server serves business logical program.

9.What is WebSphere?
   WebSphere is brand name of different products in IBM like WebSphere Application Server, WebSphere Message broker,WebSphere Process Server, WebSphere MQ....

10.What is WebSphere Application Server?
   WebSphere Application Server(WAS) is IBM run time environment for java Enterprise Edition/J2EE applications like Enterprise applications,Web Module Applications,EJB,JMS,Web Services....
 key features
     So flexible for Administration
     IBM support
     More application runs on WAS
     Monitoring Tool (PMI) (Plug-in and play)
     No of Containers.

11.What is cell?
    A cell is a group of nodes in a single administration domain.
    A cell is a virtual unit that is built of a deployment manager and one or more nodes.

12.What is Deployment Manage(dmgr)?
    A deployment manager provides management capability for multiple federated nodes.A deployment manager can manage nodes that span multiple systems and platforms.(From IBM).
    The deployment manager is a process responsible for managing the installation and maintenance of applications,Connection Pools and other resources related to a J2EE environment. It is also responsible for centralizing user repositories for application and also for WebSphere authentication and authorization.
     A deployment manager is a server that manages or administrate the operations for a logical group or other servers.

13.What is Node?
     A node is an administrative grouping of application servers for configuration and operational management within one operation system instances.
     The node is another virtual unit that is built of node agent and one or more server instances.
     Node is a logical grouping of managed servers.

14.What is Node Agent?
     The Node Agent is the process responsible for spawning server process and also responsible for configuration synchronization between the deployment manager and  the node.
     In distributed server configurations, each node has a node gent that works with the deployment manager to manage administration process.
     A node agent's purpose is to pass information between the deployment and the application server.

15.What is Cluster?
     A cluster is a group of servers that are managed together.
          In case of WAS, It is a logical grouping of application server process, running the same set of enterprise applications and the weighted workload capacity that is associated with these servers.

16.What is Horizontal Clustering?
     Horizontal clustering, sometimes referred to as scaling out, is adding physical machines to increase the performance or capability of a cluster pool.
     Here we are creating all the cluster members under different boxes. If any one of the cluster member is down or completely machine gets crashes at the time also end users can access application from other cluster member which is running on other host.

17.What is Vertical Clustering?
     Vertical clustering, sometimes referred to as scaling up, is adding WebSphere Application Server instances to the same machine.
     Here we are creating all the cluster members under same box. If any one of the cluster member is down request will be routed to another cluster members.

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