UNDERSTANDING WEBLOGIC DOMAIN

Agenda• Domain• Overview of Weblogic Server Domain• Admin Server• Managed Server• Resources and Services• Standalone v/s Clustered Managed Servers• Nodemanager• Clusters

Domain

• A domain consists of one or more WebLogic Server instances which are managed by a Admin Server

• A domain can contain:1. Admin Server2. Managed Server3. Cluster4. Resources and Services etc. .

• Modes of Domain1. Development Mode2. Production Mode

• Common Domain Types1. Domain with Managed Servers2. Standalone Server Domain

Overview of Weblogic Domains

Admin Server

Resources and Services

Resources and Services

Resources and Services

Managed Server

Managed Server

Managed Server

Resources and Services

Managed Server

Managed Server

Managed Server

Cluster

Admin Server

Roles of Admin Server:• Act as a central control entity to configure

the entire domain. That is, helping in configuring Managed servers, clusters etc..

• The Administration Server serves as a central location from which we manage and monitor all resources in a domain.

• It maintains the domain's configuration artifacts and distributes configurations to Managed Servers.

Managed Servers

Admin Server

config.xml

What happens if Admin Server Fails ?• No Configuration changes can be made• Does not affect the operation of Managed Servers in the

domain• Managed Servers and Clusters configured will continue to

run• Load Balancing and Fail Over remains Available

Managed Server

In a domain, server instances other than the Administration Server are referred to as Managed Servers

Functionality of Managed Server:•Helps in hosting Applications.•One or More Managed servers can be grouped to form clusters.

Resources and Services

A domain contains resources and services needed by Managed Servers and applications deployed in the domain

Examples:Application components, such as Web Applications, J2EE Connectors and Enterprise ApplicationsJDBC connection poolsJMS servers etc..

Standalone v/s Clustered Managed Servers

Stand Alone MS Clustered MS

No Load Balancing or Fail Over Mechanisms

Load Balancing and Fail Over Mechanisms are present

Not Scalable, reliable and Highly Available

Scalable, reliable and highly available

Commonly used in hosting small apps Used in all Production Environments

Server Life Cycle

Nodemanager

• NodeManager is a java utility that helps to perform common operational task on Managed Server.

• Runs as a separate process from weblogic server.• Useful in production environments where the managed

servers are distributed across multiple machines

Nodemanager capabilities

• Node Manager enables you to perform these tasks:

1. Start and stop remote Managed Servers.2. Monitor the health of Managed Servers and automatically

kill server instances whose health state is "failed".3. Automatically restart Managed Servers that have the

"failed" health state, or have shut down unexpectedly due to a system crash or reboot.

Start Managed Server

Shutdown Managed ServerStop a managed server.Shutdown a failed managed server

Restart Managed ServerNumber of attemptsTime-Span.

What happens if Nodemanager fails?

• Do not shut down the managed server which the node manager was monitoring.

• Node manager must be restarted either by the operating system or manually

CLUSTER

Cluster• Multiple Weblogic server instances running simultaneously

to provide scalability and reliability• Cluster capacity can be increased dynamically by adding

additional server instances to cluster

Cluster 1

Cluster 2

Admin Server

Cluster Scaling

• Horizontal Scaling• Vertical Scaling

Benefits Of Clustering

• Reliable• Scalability• High-Availability

Key Capabilities of a Cluster

• Application Failover• Load Balancing

Application Failover Failover means “an application component doing a particular “job”—

some set of processing tasks—becomes unavailable for any reason”

Copy of failed object

Failed Object

Copy

Available?

YES (mandatory)

Information should be made available to all other objects and program that handles failover.Location and operational status of all object

Object taking over an interrupted job knows how much of the job was completed before the first object failed

Picking up from where it had failed

Load Balancing

For load balancing to occur:• There must be multiple copies of an object that can do a particular job.• Information about the location and operational status of all objects

must be available.

• Load balancing is the even distribution of jobs and associated communications across resources in the environment

Load Balancer

Application Instance 1

Application Instance 2

Application Instance 3

Domain

Admin Server

Differences

Resources

Overview

Nodemanager

Managed Server Cluster

Summary