Date post: | 16-Jul-2015 |
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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