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Redpaper WebSphere Application Server V7.0: Technical Overview WebSphere® Application Server is the implementation by IBM® of the Java™ Platform, Enterprise Edition (Java EE) platform. It conforms to the Java EE 5 specification. WebSphere Application Server is available in unique packages that are designed to meet a wide range of customer requirements. At the heart of each package is a WebSphere Application Server that provides the runtime environment for enterprise applications. This discussion centers on the runtime server component of WebSphere Application Server. For more information about topics discussed in this paper, refer to the IBM Redbooks® publication WebSphere Application Server V7: Concepts, Planning and Design, SG24-7708. Arden Agopyan Hermann Huebler Tze Puah Thomas Schulze David Soler Martin Keen © Copyright IBM Corp. 2009. All rights reserved. ibm.com/redbooks 1 WebSphere Application Server packaging WebSphere Application Server comes in several packaging options. In addition to the application server component, each package contains an appropriate combination of complementary products (for example, IBM HTTP Server, Rational® Application Developer Assembly and Deploy, Edge components, and so on). Distributed platforms WebSphere Application Server V7.0 has the following packaging options for distributed platforms, including IBM AIX®, HP-UX, Linux®, Solaris™, and Microsoft® Windows®: � IBM WebSphere Application Server - Express V7.0, referred to as Express For more information about Express, see the following Web page: http://www.ibm.com/software/webservers/appserv/express/ � IBM WebSphere Application Server V7.0, referred to as Base For more information about Base, see the following Web page: http://www.ibm.com/software/webservers/appserv/was/ � IBM WebSphere Application Server Network Deployment V7.0, referred to as Network Deployment For more information about Network Deployment, see the following Web page: http://www.ibm.com/software/webservers/appserv/was/network/ System z For WebSphere Application Server on System z®, IBM WebSphere Application Server for z/OS® V7.0, a full-function version of the Network Deployment product is available. For more information about WebSphere Application Server for z/OS V7.0, see the following Web page: http://www.ibm.com/software/webservers/appserv/zos_os390/ 2 WebSphere Application Server V7.0: Technical Overview System i WebSphere Application Server on System i® has the following packaging options: � IBM WebSphere Application Server V7.0 for IBM i � IBM WebSphere Application Server for Developers V7.0 for IBM i � IBM WebSphere Application Server Network Deployment V7.0 for IBM i � IBM WebSphere Application Server - Express V7.0 for IBM i For more information about WebSphere Application Server on System i, see the following Web page: http://www.ibm.com/servers/eserver/iseries/software/websphere/wsappserver/ Application support WebSphere Application Server V7.0 can run the following types of applications: � Java EE applications � Portlet applications � Session Initiation Protocol (SIP) applications � Business level applications Java EE applications The Java EE specification is the standard for developing, deploying, and running enterprise applications. WebSphere Application Server V7.0 provides full support for the Java EE 5 specification. The Java EE programming model has multiple types of application components: � Enterprise beans � Servlets and JavaServer™ Pages files � Application clients The primary development tool for WebSphere Application Server Java EE 5 applications is Rational Application Developer for WebSphere V7.5. The Rational Application Developer Assembly & Deploy V7.5, shipped with WebSphere Application Server, contains the tools needed to create, test, and deploy Java EE 5 applications. It includes full support for the new features of Java SE 6.0. Applications are packaged as enterprise application archives (EAR files). For information about the Java EE specification, see the following Web page: http://java.sun.com WebSphere Application Server V7.0: Technical Overview 3 Portlet applications The Portlet container in WebSphere Application Server V7.0 provides the runtime environment for JSR 268 compliant portlets. Portlet applications are intended to be combined with other portlets collectively to create a single page of output. The primary development tool for portlets on WebSphere Application Server portlet applications is Rational Application Developer for WebSphere V7.5. You can also use Rational Application Developer Assembly & Deploy V7.5, which is shipped with WebSphere Application Server. Portlets are packaged in WAR files. The portlet runtime does not provide the advanced capabilities of WebSphere Portal, such as portlet aggregation and page layout, personalization and member services, or collaboration features. For more information about JSR 286, see the following Web page: http://jcp.org/en/jsr/detail?id=286 Session Initiation Protocol applications Session Initiation Protocol (SIP) applications are Java programs that use at least one SIP servlet written to the JSR 116 specification. SIP is used to establish, modify, and terminate multimedia IP sessions. SIP negotiates the medium, the transport, and the encoding for the call. After the SIP call has been established, the communication takes place over the specified transport mechanism, independent of SIP. Examples of application types that use SIP include voice over IP, click-to-call, and instant messaging. Rational Application Developer Assembly & Deploy V7.5 provides special tools for developing SIP applications. SIP applications are packaged as SIP archive (SAR) files, and are deployed to the application server using the standard WebSphere Application Server administrative tools. SAR files can also be bundled in a Java EE application archive (EAR file), similar to other Java EE components. For more information about SIP applications, see the following Web pages: � JSR 116 SIP Servlet API 1.0 Specification http://www.jcp.org/aboutJava/communityprocess/final/jsr116/ � JSR 116 http://jcp.org/en/jsr/detail?id=116 � RFT 3261 http://www.ietf.org/rfc/rfc3261.txt 4 WebSphere Application Server V7.0: Technical Overview Business level applications A Business level application is a notion of an application beyond Java EE’s definition. This is a new administration concept that expands the options previously offered by Java EE. This grouping notion for enterprise-level applications includes WebSphere and non-WebSphere artifacts like Service Component Architecture (SCA) packages, libraries, and proxy filters under a single application definition (Figure 1). Every artifact in the group is a composition unit. Figure 1 Business level applications A business level application can be useful when an applicationhas the following characteristics: � Is composed of multiple packages � Applies to the post-deployment side of the application life cycle � Contains additional libraries, or non-Java EE artifacts � Includes artifacts that run on heterogeneous environments that include WebSphere and non-WebSphere runtimes � Is defined in a recursive manner (for example, if an application includes other applications) BLA1 EJB Module Web Module BLA3 BLA2 Java EE Enterprise Application JAR Business Logic Configuration Composition JAX-WS Web Service Module Portlet Module Java Library DB2 Database CICS TransactionJava Library Axis2 PAR JAR EARWAR WebSphere Application Server V7.0: Technical Overview 5 Application server configurations At the heart of each member of the WebSphere Application Server family is an application server. Each family has essentially the same architectural structure. Although the application server structure for the Base and Express platforms is identical, there are differences in licensing terms and platform support. With the Base and Express platforms, you are limited to stand-alone application servers. The Network Deployment platform enables more advanced topologies that provide workload management, scalability, high availability, and central management of multiple application servers. You can also manage multiple Base profiles centrally, but you will not have workload management, scalability, and high availability capabilities. Runtime environments are built by creating profiles. A profile can define a deployment manager, a stand-alone application server, or an empty node to be federated (added) to a cell. Each profile contains files specific to that runtime (such as logs and configuration files). Profiles can be created during and after installation. After the profiles have been created, further configuration and administration is performed using the WebSphere administrative tools. Stand-alone application servers All WebSphere Application Server packages support a single stand-alone server environment. With this configuration, each application server acts as an unique entity. An application server runs one or more applications and provides the services required to run those applications. Each stand-alone server is created by defining an application server profile. See Figure 2. Figure 2 Stand-alone application server configuration System A Application Server Application Server Application Server Integrated Solutions Console Integrated Solutions Console Integrated Solutions Console 6 WebSphere Application Server V7.0: Technical Overview A stand-alone server can be managed from its own administrative console and functions independent from all other application servers. You can also use WebSphere Application Server’s scripting facility, wsadmin, to perform every function that is available in the administrative console application. Multiple stand-alone application servers can exist on a machine, either through independent installations of the WebSphere Application Server product binaries, or by creating multiple application server profiles within one installation. Stand-alone application servers do not provide workload management or failover capabilities. They run isolated from each other. With WebSphere Application Server for z/OS, it is possible to use workload load balancing and response time goals even on a transactional base, as well as a special clustering mechanism, the multi-servant region, with a stand-alone application server. Distributed application servers With the Network Deployment packaging, you can build a distributed server configuration to enable central administration, workload management, and failover. In this environment, you integrate one or more application servers into a cell that is managed by a central administration instance, a deployment manager. The application servers can reside on the same machine as the deployment manager or on multiple separate machines. Administration and management is handled centrally from the administration interfaces by the deployment manager. An example is shown in Figure 3. Figure 3 Distributed application servers with WebSphere Application Server V7.0 System BSystem A Application Server Application Server Integrated Solutions Console Application Server Deployment Manager WebSphere Application Server V7.0: Technical Overview 7 With a distributed server configuration, you can create multiple application servers to run unique sets of applications and manage those applications from a central location. More importantly, you can cluster application servers to allow for workload management and failover capabilities. Applications that are installed in the cluster are replicated across the application servers. When one server fails, another server in the cluster continues processing. Workload is distributed among Web and EJB™ containers in a cluster using a weighted round-robin scheme, or randomly, depending upon your configuration. In z/OS the weighted round-robin mechanism is replaced by the integration of WebSphere Application Server for z/OS in the Workload Manager (WLM), that is an integral part of the operating system. This allows requests to be dispatched to a cluster member according to real-time load and whether or not the member reaches its defined response time goals. It is also possible to replicate sessions saved in an application server of the cluster to other cluster members with the session replication feature of WebSphere Application Server. A distributed server configuration can be created in one of three ways: � Create a deployment manager profile to define the deployment manager. Then, create one or more custom node profiles. The nodes defined by each custom profile can be federated into the cell managed by the deployment manager during profile creation or later, manually. The custom nodes can exist inside the same operating system image as the deployment manager or in another operating system instance. Application servers can then be created using the Integrated Solutions Console or wsadmin scripts. � Create a deployment manager profile to define the deployment manager. Then, create one or more application server profiles and federate these profiles into the cell managed by the deployment manager. This process adds both nodes and application servers into the cell. The application server profiles can exist on the deployment manager system or on multiple separate system or z/OS image. � Create a cell profile. This actually creates two profiles: a deployment manager profile and a federated application server profile. Both reside on the same machine. 8 WebSphere Application Server V7.0: Technical Overview Application servers concepts Regardless of the configuration, WebSphere Application Server is organized based on the concept of cells, nodes, and servers. Although all of these elements are present in each configuration, cells and nodes do not play an important role until you take advantage of the features provided with Network Deployment. These cells, nodes, and servers can be managed by a combination of deployment managers, administrative agents, and job managers. Application servers The application server is the primary runtime component in all configurations and is where an application actually executes. All WebSphere Application Server configurations can have one or more application servers. In the Express and Base configurations, each application server functions as a separate entity. There is no workload distribution or central administration among application servers. With Network Deployment, you can build a distributed server environment consisting of multiple application servers maintained from a central administration point. In a distributed server environment, you can cluster application servers for workload distribution and failover. Nodes, node groups, and node agents This section defines node related concepts. Nodes A node is an administrative grouping of application servers for configuration and operational management within one operating system instance (virtualization allows multiple operating systems on one machine). It is possible to create multiple nodes inside one operating system instance, but a node cannot leave the operating system boundaries. In a stand-alone application server configuration, there is only one node. With Network Deployment, you can configure a distributed server environment consisting of multiple nodes that are managed from one central administration server. See Figure 4 on page 10. WebSphere Application Server V7.0: Technical Overview 9 Figure 4 Node concept in a WebSphere Application Server network deployment configuration Node agents In distributed server configurations, each node has a node agent that works with the deployment manager to manage administration processes. See Figure 4. A node agent is created automatically when you add (federate) a stand-alone node to a cell. It is not included in Base and Express configurations. Node groups A node group is a grouping of nodes within a cell that have similar capabilities. A node group validates that the node is capable of performing certain functions before allowing them. For example, a cluster cannot contain both z/OS nodes and nodes that are not z/OS-based. In this case, you can define multiple node groups: one for the z/OS nodes and one for nodes other than z/OS. A DefaultNodeGroup is automatically created. This node group contains the deployment manager and any new nodes with the same platform type. A node can be a member of more than one node group. On the z/OS platform, a node must be a member of a system complex (sysplex) node group. Nodes in the same sysplex must be in the same sysplex node group. A node can be in one sysplex node group only. System A System B Node02 Application Server Integrated Solutions Console Node03 Application Server Deployment Manager Node01 Application Server Node Agent Node Agent Node Agent 10 WebSphere Application Server V7.0: Technical Overview Cells A cell is a grouping of nodes into a single administrative domain. In the Base and Express configurations, a cell contains one node. That node contains one server. See Figure 5. Figure 5 Cell component in a WebSphere Application Server topology In a Network Deployment environment, a cell can consist of multiple nodes (and node groups), which are all administered from a single point, the deployment manager. See Figure 5. If your cell configuration contains nodes running on the same platform, it is called a homogeneous cell. It is also possible to have a cell made up of nodes on mixed platforms. This is referred to as a heterogeneous cell. WebSphere Application Server V7.0 Network Deployment environment WebSphere Application Server V7.0 stand-alone environment Integrated Solutions Console System BSystem A Cell Node02 Application Server Node03 Application Server Deployment Manager Node01 Application Server Node Agent Node Agent Node Agent System A Integrated Solutions Console Integrated Solutions Console Cell01 Application Server Node01 Cell01 Application Server Node01 WebSphere Application Server V7.0: Technical Overview 11 Deployment managers The deployment manager is the central administration point of a cell, which consists of multiple nodes and node groups in a distributed server configuration. The deployment manager uses the node agent to manage the applications servers within one node. A deployment manager provides management capability for multiple federated nodes and can manage nodes that span multiple systems and platforms. A node can only be managed by a single deployment manager, and must be federated to the cell of that deployment manager. The configuration and application files for all nodes in the cell are centralized into a master configuration repository. This centralized repository is managed by the deployment manager and synchronized with local copies that are held on each of the nodes. See Figure 6. Figure 6 Configuration repositories in a network deployment installation System BSystem A Cell Node02 Application Server Integrated Solutions Console Node03 Application Server Deployment Manager Node01 Application Server Node Agent Node Agent Node Agent Master configuration repository Local configuration Local configuration Local configuration 12 WebSphere Application Server V7.0: Technical Overview Administrative agents An administrative agent is a component that provides enhanced management capabilities for stand-alone (Express and Base) application servers. This is a new concept introduced with WebSphere Application Server V7.0. In previous versions of WebSphere Application Server, each stand-alone server