IBM WebSphere Application Server (Clustering) Concept, Components. Content is adopted from IBM RedBook

1. © 2010 IBM Corporation
WebSphere
WebSphere Application Server
Clustering
Eryan Ariobowo – WebSphere Technical Specialist
Jan 2012

2. © 2010 IBM Corporation
Application Server
 The platform on which Java language-based applications run.
 It provides services that can be used by business applications, such as database
connectivity, threading, and workload management.
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3. © 2010 IBM Corporation
Application Server Architecture
 Internal architecture of WebSphere Application Server, and packaging structure
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Available in ND platform only.
Base and Express doesn’t have this capability

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Application Server Architecture V8.5
 Internal architecture of WebSphere Application Server, and packaging structure
Base & Express Network Deployment

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Server
 Server is a regular Java process responsible for serving J2EE requests (eg.: serving
JSP/JSF pages, serving EJB calls, consuming JMS queues, etc).
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Stand-Alone Application Servers
 each application server acts as a unique entity (functions independent from all others)
 each can be managed from its own administrative console
 stand-alone servers can be managed from a central point by using administrative agents
and a job manager
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Administrative Agent (Admin Agent)
 An additional administration component
(available since V7)
 A single interface to administer multiple
unfederated/stand-alone application server
(Express & Base) nodes in different
environments
 Multiple application servers in the same machine
can be administer by one administrative agent.
 The administrative agent and application servers
must be on the same machine
 A node can be registered with the administrative
agent or federate the node with a deployment
manager, but you cannot do both
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Distributed Application Servers
 a distributed server configuration
– built by the Network Deployment packaging
– enable central administration, workload management, and failover
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Node, Node Agent
 Node
– An administrative grouping of
application servers for
configuration and operational
management within one operating
system instance
– Multiple nodes can be created inside
one operating system instance
 Node Agent
– Process responsible for spawning
and killing server processes and also
responsible for configuration
synchronization between the
Deployment Manager and the Node.
– Created automatically when you add
(federate) a stand-alone application
server node to a cell
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Stand-alone environment
Distributed environment

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Node Group
 A collection of nodes within a cell that have similar capabilities in terms of
installed software, available resources, and configuration
 Used to define a boundary for server cluster formation
 DefaultNodeGroup
– contains the deployment manager and any new nodes with the same platform
type
– created automatically.
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11. © 2010 IBM Corporation
Profiles
 Runtime environments are built by creating profiles.
 Product files
– a set of read-only static files or product binary files that are shared by any instances
of the WebSphere Application Server product.
 Configuration files (profiles)
– a set of user-customizable data files. This file set includes WebSphere configuration,
installed applications, resource adapters, properties, log files, and so on.
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Profiles
 Each profile is stored in a unique directory path
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Profile Types
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Product WebSphere profiles available
WebSphere Application Server
Express ► Application server profiles (stand-alone)
► Management profile with an administrative agent server
WebSphere Application Server
(Base)
WebSphere Application Server
Network Deployment (ND)
► Management profile with a deployment manager server
► Management profile with an administrative agent server
► Management profile with job manager server
► Application server profiles (stand-alone)
► Cell profile
► Custom profile
► Secure proxy profile

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Profile Types
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Single aplication server profile
• consists of one cell, one node, and one server
• has a dedicated administrative console
Deployment Manager profiles
• A cell for the administrative domain
• A node for the deployment manager
• A deployment manager with an administrative console
• No application servers
Cell profile
• Combination of two profiles: a deployment manager profile & an application server profile
• Deployment manager and application server reside on the same system
Administrative Agent profile
• created on the same node as the stand-alone servers
• can manage only servers on that node
Job Manager profile
• queue jobs to application servers in a flexible management environment

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Profiles
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node1
server1
dmgrNode
dmgr
dmgrCell dmgr profile
nodeagent1
server2
node2
nodeagent2
profile2
adminconsole
addnode
profile1
adminconsole
 Note: Node of WAS Base/Express can be added to a Deployment Manager

16. © 2010 IBM Corporation
Cell
 A grouping of nodes into a single administrative domain.
 A cell can consist of multiple nodes and node groups.
 In the Base and Express configurations:
– contains one node and that node contains one server
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Cell in Stand-alone & Network Deployment Environment
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Cell in ND Environment – Deployment Manager
 A Cell is a virtual unit that is built of a Deployment Manager and one or more nodes.
 The Deployment Manager is a process (in fact it is an special WAS instance) responsible
for
– Managing the installation and maintenance of Applications
– Connection Pools and other resources related to a J2EE environment
– Centralizing user repositories for application
– Centralizing WAS authentication and authorization.
 Can contains nodes that are running on mixed platform (heterogeneous cell)
Node 1 Node 2 Node 2 Node 2
Deployment
Manager

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Integrated Solutions Console (administrative console)
 connects to
– a running stand-alone server OR
– a deployment manager (in a distributed environment)
 In WAS > V7, it also connects to an administrative agent and a job manager
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20. © 2010 IBM Corporation
Cluster
 virtual units that groups Servers
 servers is managed together
 resources added to the Cluster are propagated to every Server that makes up the cluster
 Provide highly available
– because requests are automatically routed to the running servers in the event of a failure
 A cell can include no clusters, one cluster, or multiple clusters
 Cluster members cannot span cells.
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A cluster is a group of application servers that collaborate for the purposes of
workload balancing and failover.

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Example Configuration
Cell, DeploymentManager, Node, NodeAgent, Server, Cluster
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Cluster
 Cluster support following types of servers
– Application server clusters
a logical collection of application server processes that provides workload balancing and
high availability. It is a grouping of application servers that run an identical set of
applications managed so that they behave as a single application server (parallel
processing).
– Proxy server clusters
consists of a group of proxy servers that can route requests and traffic to applications in
a cell
– Generic server clusters
allows you to configure external servers (non-IBM application servers or a pre-V6
WebSphere Application Server) into a logical cluster that can be used by the proxy
server to route requests
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Vertical & Horizontal Clustering (Scaling)
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Vertical Horizontal

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Mixed Clustering (Horizontal & Vertical)
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Mixed-node version in a cluster
 WAS V7 can contains nodes &
server from WAS V5.1, V6.0,
V6.1 ,and V7.0
 WAS V8 can contains nodes &
server from WAS V6, V6.1, V7,
and V8
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Job Manager
 Allows the management of multiple WAS domains (multiple deployment managers and
administrative agents) through a single administration interface.
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Web Server
 Web servers are independent products i.e. IBM HTTP Server (HIS)
 Managed Node
– Can be defined to and managed by the administration process through Deployment
Manager
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Web Servers
 Unmanaged Node
– Manually transfer the web server plug-in configuration file to the web server on an
unmanaged node
– Still can be administered from the Integrated Solutions Console; push/upload the plug-in
configuration file to web server from admin console through HTTP
• does not require a node agent
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29. © 2010 IBM Corporation
Web server plug-in
 Used to route requests to one of multiple application servers
 Uses the plug-in configuration file (plugin-cfg.xml) to determine if a request should be
handled by the web server or forwarded to an application server
 Request transmitted to application server can be HTTP or HTTP Secured (HTTPS).
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Edge Components
 Caching Proxy
– Reverse Caching Proxy
– Forward Caching Proxy
 Load Balancer
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31. © 2010 IBM Corporation
Edge Components: Caching Proxy
 Intercepts requests from the client, retrieves the requested information from the content-
hosting systems (usually local cache), and delivers that information back to the client
 Cacheable content examples:
– static Web pages
– JavaServer Pages files that contain dynamically generated, but infrequently changing,
information
 Cache storage
– physical storage device that uses raw disk caching (writes directly without using the
operating system's read and write protocols)
Use htcformat command for preparing storage device for a disk cache
– system memory
 Cache index
– uses system memory space to hold an index of the cache
– reduces the processing time to find cached files.
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