Oracle9i Application Server Migrating from Oracle Application Server Release 1 (v1.0.2.2) Part Number A83709-07 |
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This chapter provides a general discussion of the Oracle9i Application Server characteristics in comparison to those of Oracle Application Server. It includes a mapping of Oracle Application Server components to their equivalent functionality in Oracle9i Application Server. The topics include:
Oracle9i Application Server is a middle-tier application server designed to enable scalability of web and database-centric applications beyond the limits of a single database instance. It offers:
The table below shows Oracle Application Server components and their corresponding functionality in Oracle9i Application Server.
This section discusses enterprise services, characteristics of a web site of concern to administrators and developers. It describes scalability, availability, fault tolerance, load balancing, and administration in Oracle Application Server and how they will work after you migrate your site to Oracle9i Application Server.
Oracle Application Server consists of the HTTP layer, the server layer, and the application layer. The HTTP listener layer is made up of the HTTP server and the dispatcher. The Server layer provides a common set of components for managing these applications. These components include load balancing, logging, automatic failure recovery, security, directory, and transaction components. The application layer is made up 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 will be serviced by that instance, otherwise a new instance will be created.
Similarly in Oracle9i Application Server, the Oracle HTTP Server and mod_jserv run in the same process. Apache JServ is a pure Java servlet engine and runs in a separate process. The Apache Web Server uses mod_jserv to route requests to an Apache JServ process, much like the dispatcher in Oracle Application Server.
Oracle Application Server can be deployed in single or multi-node environments. Similarly, the Oracle HTTP Server and Apache JServ can be configured for single or multi-node environments.
In Oracle Application Server, each listener can accommodate 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.
On UNIX platforms, Oracle HTTP Server creates a pool of child processes ready to handle incoming client requests, on start-up. As the requests are processed and the load increases, the server spawn new processes for subsequent requests. The initial and maximum size of the pool, and the min/max number of spare server processes, is configured with the StartServers
, MaxClients
, MinSpareServers
and MaxSpareServers
directives respectively.
On Windows NT, 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 HTTP Server to run multiple instances on the same host, each of them using a different IP address/TCP port combination, or on different hosts.
In Oracle Application Server, as the number of requests increases, the system creates new cartridge servers and new instances in them.
In Oracle HTTP Server, mod_jserv receives requests from the server and routes them to Apache JServ, the servlet engine.
Apache Jserv runs all servlets within servlet zones. Some of the advantages are: better security, the ability to run multiple JVMs, and support for multiple virtual hosts.
When a component such as a listener or a cartridge server fails, Oracle Application Server detects the failure and restarts the failed component, restoring any preserved state information when possible.
In Oracle HTTP Server, if there is more than one server host, or more than one JServ host, and one of them stops, the system will still work as long as there is one server and one JServ running. A last known status is maintained for every JServ, and any Oracle HTTP Server instance can route a request to any Apache JServ.
In Apache, the administrator is responsible for restarting any failed Apache Web Server or Apache Jserv instances.
Oracle Application Server allocates system resources and prioritizes requests based on two types of load balancing methods: priority-based and min/max.
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 min/max mode, you set the number of instances, threads and client parameters for each cartridge at the cartridge level.
In Oracle HTTP Server, you define the number of JServ hosts, host weight, and a logical set of these hosts in your configuration file. The system assigns incoming requests to JServ instances. If a JServ instance fails, requests are redirected to the other members of the logical set.
Oracle Application Server provides GUI tools and built-in support for administering and monitoring your site, listeners, and applications. The configuration data from the OAS Manager tool is stored in various configuration files.
In Oracle HTTP Server, you perform site administration and maintenance by editing the Apache server and Apache JServ configuration files. The difference from Oracle Application Server in the number and type of configuration files is significant.
Oracle Application Server supports a number of different security schemes for both user and host authentication, SSL, and the Oracle Wallet Manager.
In Oracle9i Application Server, Apache JServ can run behind a firewall (the AJP protocol uses only one TCP port). It uses ACL (allowing AJP requests only from hosts with ACL) and supports SSL.
Oracle9i Application Server includes a tool to migrate Oracle Application Server private key files into OpenSSL PEM format private key files. The full path to the tool is ORACLE_HOME
/Apache/Apache/bin/pconvert
(UNIX) ordrive
:\Oracle\iSuites\Apache\Apache\bin\pconvert.exe
(Windows).
The syntax for running pconvert
is
pconvert -s oas_private_key_file -d ias_private_key_file
The following steps guide you through the process of converting an Oracle Application Server private key to a Oracle9i Application Server private key.
prompt> pconvert -s oaskey.der -d iaskey.pem Thank you! Your OAS private key has been converted to OPENSSL private key!
opensll
tool with the rsa
argument. The full path to the tool is ORACLE_HOME
/Apache/open_ssl/bin/openssl
(UNIX) ordrive
:\Oracle\iSuites\Apache\open_ssl\bin\openssl.exe
(Windows).
prompt> openssl rsa -in iaskey.pem -des3 -out iaskey_enc.pem read RSA key writing RSA key Enter PEM pass phrase: (input not shown) Verifying password - Enter PEM pass phrase: (input not shown)
ssl.key
directory. The full path of the directory is ORACLE_HOME
/Apache/Apache/conf/ssl.key/
(UNIX) ordrive
:\Oracle\iSuites\Apache\Apache\conf\ssl.key\
(Windows).
ssl.crt
directory. The full path of the directory is ORACLE_HOME
/Apache/Apache/conf/ssl.crt/
(UNIX) ordrive
:\Oracle\iSuites\Apache\Apache\conf\ssl.crt\
(Windows).
SSLCertificateFile
parameter to the full path and filename of the Oracle Application Server certificate file from step 4. For example:
(UNIX) SSLCertificateFile ORACLE_HOME/Apache/Apache/conf/ssl.crt/oascert.crt (Windows) SSLCertificateFile \conf\ssl.crt\oascert.crt
SSLCertificateKeyFile
to the full path and filename of the converted private key file from step 3.
(UNIX) SSLCertificateKeyFile ORACLE_HOME/Apache/Apache/conf/ssl.key/iaskey.pem (Windows) SSLCertificateKeyFile \conf\ssl.key\iaskey.pem
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