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Introduction to Oracle Application Server 10g

This chapter provides a general discussion of the Oracle Application Server 10g characteristics in comparison to those of Oracle Application Server. It includes a mapping of Oracle Application Server components to their equivalent functionality in Oracle Application Server 10g.

Topics discussed are:

• What is Oracle Application Server 10g?

• Oracle Application Server Component Migration Options

• Enterprise Services Migration

What is Oracle Application Server 10g?

Oracle Application Server 10g provides full support for the Java 2 Platform Enterprise Edition (J2EE), XML, and emerging Web services standards. With Oracle Application Server 10g, you can simplify information access for your customers and trading partners by delivering enterprise portals, which can be customized and accessed from a network browser or wireless devices. It allows you to redefine your business processes, and integrate your applications and data sources with those from your customers or partners. You can deliver tailored customer experiences via real-time personalization, and assess and correlate Web site traffic patterns using Oracle Application Server 10g integrated business intelligence services.

You can also implement a centralized management, security, and directory framework to manage and monitor all of your distributed systems and diverse user communities. Oracle Application Server 10g allows you to save on Web site infrastructure by deploying your fast, scalable Internet applications through built-in Web caching, load balancing and clustering capabilities.

See Also: Oracle Application Server 10g Concepts

Oracle Application Server Component Migration Options

Table 1-1 presents Oracle Application Server components and their corresponding functionality in Oracle Application Server 10g, as well as the chapter in this guide that contains detailed information regarding specific components. During the migration process, you must migrate Oracle Application Server components to their closest corresponding components in Oracle Application Server 10g.

Table 1-1 Comparison of Application Server Components  

Oracle Application Server Component	Closest Oracle Application Server 10g Equivalent Component	Reference
JWeb application	Oracle Application Server Containers for J2EE (OC4J) application	Chapter 2
JServlet application	OC4J application	Chapter 2
LiveHTML application	Apache SSI and JavaServer Page (JSP) applications	Chapter 3
Perl application	mod_perl application	Chapter 3
CWeb application	Custom Apache Modules, Common Gateway Interface (CGI), FastCGI, Java Native Interface (JNI)	Chapter 3
PL/SQL application	mod_plsql application	Chapter 3
ECO/Java application	OC4J application	Chapter 4
EJB application	OC4J application	Chapter 4
JCORBA application	OC4J application	Chapter 4

Enterprise Services Migration

This section discusses enterprise services and characteristics of a Web site of concern to administrators and developers. The following topics are discussed:

• Overview

• Scalability

• Availability and Fault Tolerance

• Load Balancing

• Administration

• Security

• Third Party Web Server Support

This section also describes whether migrating your Web site from Oracle Application Server to Oracle Application Server 10g affects these characteristics.

Overview

Oracle Application Server consists of three layers, the HTTP listener layer, the server layer, and the applications layer. The HTTP listener layer consists of listeners, adapter interface, and dispatchers. The server layer provides a common set of components for managing applications. These components include load balancing, logging, automatic failure recovery, security, directory and transaction management components. The application layer consists of applications, cartridges, and cartridge servers. When a request arrives, the dispatcher routes the request to the application server layer, and if a cartridge instance is available, the request is serviced by that instance. Otherwise, a new instance is created.

See Also: Oracle Application Server Overview and Glossary

In Oracle Application Server 10g, Oracle HTTP Server handles load balancing, routing servlet requests to OC4J through mod_oc4j, single sign-on authentication and security context propagation through mod_osso and SSL. OC4J consists of pure J2EE containers for running JSPs, servlets, and EJBs, and provides J2EE container services. Both the Oracle HTTP Server and OC4J perform the same functions as three layers in Oracle Application Server.

Scalability

You can deploy Oracle Application Server in single or multiple host environments. You can configure Oracle HTTP Server and OC4J for single or clustered host environments.

Oracle HTTP Server

In Oracle Application Server, each listener accommodates a maximum number of concurrent connections. This number varies based on operating system restrictions. To distribute the request load on a site, you can create multiple listeners, each listening on a different TCP port.

For Oracle Application Server 10g on UNIX, Oracle HTTP Server creates a pool of child processes ready to handle incoming client requests during the startup. As the requests load increases, the server spawns new processes for subsequent requests. The initial and maximum size of the pool, and the minimum or maximum number of spare server processes is configured with the StartServers, MaxClients, MinSpareServers and MaxSpareServers directives, respectively.

For Oracle Application Server 10g on Windows, Oracle HTTP Server runs as a multi-threaded process. The number of simultaneous connections is configured with the ThreadsPerChild directive, which is analogous to both the StartServers and MaxClients directives for UNIX.

You can configure Oracle Application Server through the Node Manager. For Oracle Application Server 10g, you can configure Oracle HTTP Server using Oracle Enterprise Manager Application Server Control, or by manually editing the httpd.conf file, which is located at:

• UNIX: ORACLE_HOME/Apache/Apache/conf/httpd.conf

• Windows: ORACLE_HOME\Apache\Apache\conf\httpd.conf

  See Also: Oracle HTTP Server Administrator's Guide Oracle Application Server 10g Administrator's Guide

OC4J

In Oracle Application Server, as the number of requests increases, the system creates new cartridge servers and new instances.

In Oracle Application Server 10g, Oracle HTTP Server's mod_oc4j receives requests from the server and routes them to the OC4J servlet container.

See Also: Oracle Application Server Containers for J2EE User's Guide for OC4J information. Chapter 2, "Migrating JWeb Applications to OC4J" Chapter 4, "Migrating EJB, ECO/Java and JCORBA Applications"

Availability and Fault Tolerance

When a component, such as a listener or a cartridge server fails, Oracle Application Server detects the failure and restarts the failed component. It restores any preserved state information, when possible.

In Oracle HTTP Server, if there is more than one HTTP server host, or more than one OC4J host, when one of the hosts stops, the system will still function as long as one HTTP server and one OC4J are running, provided that J2EE components have been deployed against the cluster of OC4J instances. Any Oracle HTTP Server instance can route a request to any OC4J instance. Maintaining routing information in cookies eliminates single point of failure.

Load Balancing

Oracle Application Server allocates system resources and prioritizes requests based on two types of load balancing methods, priority-based method and minimum or maximum-based method.

In priority mode, the system manages and allocates resources automatically, based on the priority level you set for your applications and cartridges. The number of processes, threads, and instances is automatically determined based on the request load and priority level of the application and components.

In minimum or maximum mode, you set the number of instances, threads and client parameters for each cartridge at the cartridge level.

In Oracle HTTP Server, you can define the number of hosts, and a logical set of these hosts in your configuration file. The system assigns incoming requests to OC4J instances.

Administration

Oracle Application Server provides GUI tools and built-in support for administering and monitoring your site, listeners, and applications. The configuration data from the Oracle Application Server Manager tool is stored in various configuration files.

In Oracle HTTP Server, you can perform site administration and maintenance using Oracle Enterprise Manager, or through a set of configuration files. Table 1-2 presents configuration files for the Oracle Application Server HTTP listener and Oracle HTTP Server.

See Also: Oracle HTTP Server Administrator's Guide Oracle Application Server 10g Administrator's Guide.

Table 1-2 Configuration Files Comparison

Oracle Application Server HTTP Listener	Oracle Application Server 10g Oracle HTTP Server
owl.cfg: list of registered listeners and their configuration settings	httpd.conf: primary (or sole) server-wide configuration file (You can choose to maintain file location and translation information in srm.conf, and security information in access.conf, or to maintain all directives in one file.)
site.app: site configuration file	(no equivalent)
svlistenerName.cfg: listener configuration file	(no equivalent)
wrb.app: process and cartridge configuration file	(no equivalent)
resources.ora: configuration file for the ORB	(no equivalent)

Security

You must convert the certificate from Oracle Application Server to Oracle Application Server 10g. The section below provides the required instructions.

Migrating Certificates

Protecting your site with SSL is one of the security measures you can take. If you have done so and want to migrate your SSL certificate to Oracle Application Server 10g, you must convert it.

Oracle Application Server 10g contains two migration tools, pconvert and ssl2ossl (UNIX) or osslconvert (Windows). Perform following steps to migrate from the Oracle Application Server certificate to an Oracle Application Server 10g certificate or wallet.

1. Convert Oracle Application Server private key to an Oracle Application Server 10g private key using the conversion tool, pconvert, which is located at:
   • UNIX: ORACLE_HOME/Apache/Apache/bin/pconvert

   • Windows: ORACLE_HOME\Apache\Apache\bin\pconvert.exe

   The syntax for running pconvert is:

   pconvert -s oas_private_key_file -d ias_private_key_file
   
   

   For example:

   prompt> pconvert -s privkey.der -d iaskey.pem
   
   

2. Generate an Oracle Application Server 10g wallet file using the Oracle Application Server certificate file and the ias_private_key file that you obtained from step 1 with the conversion tool, ssl2ossl or osslconvert. The full paths to the tools are:
   • UNIX: ORACLE_HOME/Apache/Apache/bin/ssl2ossl

   • Windows: ORACLE_HOME\Apache\Apache\bin\osslconvert.exe

   The syntax for running ssl2ossl on UNIX is:

        ssl2ossl -cert oas_certificate_file
                 -key ias_private_key_file
                 -wltpass password_for_wallet
                 -certpass password_for_oas_certificate_file
                 -chain oas_certificate_chain_file
                 -capath oas_certificate_authority_path
                 -cafile oas_certificate_authority_file
                 -wallet wallet_full_path
                 -ssowallet yes/no
                 -validate yes/no
   
   

   The syntax for running osslconvert on Windows is:

        osslconvert.exe -cert oas_certificate_file
                        -key ias_private_key_file
                        -wltpass password_for_wallet
                        -certpass password_for_oas_certificate_file
                        -chain oas_certificate_chain_file
                        -capath oas_certificate_authority_path
                        -cafile oas_certificate_authority_file
                        -wallet wallet_full_path
                        -ssowallet yes/no
                        -validate yes/no
   
   

Table 1-3 summarizes the parameters and their associated requirements for the ssl2ossl or osslconvert conversion tool.

Table 1-3 Summary of ssl2ossl or osslconvert Tool Parameters  

Parameter	Description	Requirement
cert	Oracle Application Server certificate file	required
key	ias_private_key_file from step 1	required
certpass	password for the certificate	optional
wltpass	password for the wallet	optional
chain	Oracle Application Server certificate chain file	optional, but of chain, capath, or cafile, at least one of these parameters are required.
capath	Oracle Application Server certificate authority path	optional, but of chain, capath, or cafile, at least one of these parameters are required.
cafile	Oracle Application Server certificate authority file	optional, but of chain, capath, or cafile, at least one of these parameters are required.
wallet	full path of your wallet file	optional, but the default path is ORACLE_HOME/Apache/Apache/conf/ssl.wlt/0
ssowallet	with a value of either yes or no	optional, the default value is no
validate	with a value of either yes or no.If yes, then the tool will not generate a wallet. If no, the tool will generate a wallet.	optional, the default value is no.

Third Party Web Server Support

Oracle Application Server 10g uses Oracle HTTP Server, and Oracle Application Server uses HTTP Server as their Web listeners. However, many companies only use Microsoft Internet Information Services (IIS), or SUN One as their corporate standard Web server.

Both Oracle Application Server and Oracle Application Server 10g support third party Web servers, such as IIS and Sun ONE.