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Tuesday 28 April 2015

13.a. WebLogic Security: SSL Configuration by Java keytool for Admin Console HTTPS

You can use SSL Listen port enabled Admin console  could be configured. but the Demo Certificates can be applicable only in the development domains. In the domain directory in the security sub directory you could get DemoTrust.jks, DemoIdentity.jks files once you enabled SSL for a WebLogic server.

What are the tools to generate private and public keys?
If you machine installed with JDK then you can use Java Development Kit have default tool keytool will be used.

Alternative to keytool you can also use the OpenSource tool openSSL.

WebLogic domain SSL configurations 1-way SSL, 2way SSL


What is SSL? Why you need SSL?
Secure Socket Layer protocol. which will be combined with other protocol to provide secure communication. Secure means the data that you sender and receiver should be protected. When outside world try to trap or open that then it is unreadable format.

Can I have different identity alias  names and trust alias?
Yes, you could have different alias names. When you deal with digital certificates you need to provide root alias, intermediate cert also different. But when you import the signed certificate it should be using same alias used when keygen was created.


What is JAAS?
Unlike many other Java Specifications, this is also Java Authorization Authentication Service specification. Know about who are connecting to your application this API gives lot of features. Identifying and what customer doing during his online shopping this would give the some kind of input for feature investments. Which is implemented successfully in many Application Servers. WebLogic allows you to configure SSL communication for web application and for RMI based t3s protocol is supported.

Where Can I buy Digital Certificates?

Certificates can be sold from Certificate Authority CA is the acronym. The digital sign request you can only do when you have created a private key in a keystore and generated a root certificate. And then submit the keystore  Some of the best CA are listed below:
  • VeriSign
  • eTrust
  • entrust
  • geotrust
What is Digital Certificate?
There are multiple ways to get digital certificate for your web[WebLogic] server side certificates. Some of the file extensions used in WebLogic admin consoles are here:
  • JKS - Java Key Store
  • JCEKS - Java Cert Key Store
  • KSS - Oracle Wallet
Root Certificate means --
Intermediate Certificate means --

After receiving the certificate authority mail from CA. They will provide you the three levels of authentication. In the Windows platform using the  Base64 X.509 stores single cert file at a time. The regular Encrypted file formats are:
  • pem
  • crt
  • cer

What is Self-Signed Certificate means?

How do I get Self signed Certificate? or What are the command sequence for Certificate generation?

Step1: Creating identity and Trust key store using JKS
Command 1 :
 keytool -genkey -alias vtkey  -keyalg RSA -keysize 1024 -validity 365 -keypass welcome1 -keystore identity.jks -storepass welcome1 



Note : List of keytool commands which are changed in java 1.6 :
  • -export, renamed to -exportcert
  • -genkey, renamed to -genkeypair
  • -import, renamed to -importcert
All previous commands are still supported in this release ( keytool in java 1.6, 1.7, 1.8 and 9 ) and will continue to be supported in future releases.

Step2: Generating Certificate signing certificate and send it to certificate signing authority

Command 2 :
keytool  -export -alias vtkey  -file root.cer -keystore identity.jks -storepass welcome1



Command 3 : importing certifacte authority issued certificate
keytool -import -alias vtkey  -file root.cer -keystore trust.jks -storepass welcome1


To see the contents of the keystore use the following command :
Command :
keytool -list -v -keystore identity.jks -storepass welcome1


To see the contents of an individual certificate ( like root.cer in our case ).
Command :
keytool -printcert -file root.cer


Copy the keystore files into the WebLogic $DOMAIN_HOME location :

Below are the steps to configure Custom Identity and Custom Trust with Weblogic Server :

Step 1 : Login to Weblogic Admin console --> Environment --> Servers -->
< server_name_where_ssl_has_to_be_configured > --> Configuration -> General --> SSL Listen Port Enabled ( Check )

Note : The default SSL Listen Port would be 7002, change it if required.


Step 2 : Click on Keystores tab under " Configuration " tab :



Step 2a : Click on the drop down menu next to Keystores and sleect " Custom Identity and Custom Trust " Step 2b : Now fill in the following information :
---Identity---
Custom Identity Keystore : < location_of_identity_keystore_that_you_have_created>

NOTE : By default WLS will look for this keystore file in domain_home location.

Custom Identity Keystore Type : jks
Custom Identity Keystore Passphrase: < This_would_be_your_storepass >

---Trust---
Custom Trust Keystore : < location_of_trust_keystore_that_you_have_created>
NOTE : By default WLS will look for this keystore file in domain_home location.
Custom Trust Keystore Type : jks
Custom Trust Keystore Passphrase: < This_would_be_your_storepass >

Step 2c : Now save the changes and click on " SSL " tab :
Private Key Alias: < This_would_be_your_certificate_alias >
Private Key Passphrase: < This_would_be_your_keypass >



Step 3 : Save the changes and click on the " >Advanced " field under the " SSL " tab :
  Set the " Hostname Verification: " to None ( from the drop down menu ).
Note : We need to select the hostname verification as None if the CN of the certificate is not the same as the hostname of the machine where WLS is installed.

Now access your Weblogic Admin console over https URL : " https://localhost:7002/console "



Click on the Advanced link and click on 'Proceed' link. This is due that we have not used the digital signature of a Certification Authority.


How to know that it is self-signed or real certificate?
All self-signed certified urls will be shows "Not Secure" as shown above. When you use the real certificates that is Certifying Authority provided certificate used then the accessing HTTPs URL without prompting loads the webpage.


References:

Monday 13 April 2015

01.c Using the WebLogic Administration Console effectively

Administration Console

The Oracle WebLogic Server Administration Console is a Web browser-based, graphical user interface that you use to manage a WebLogic domain.

WebLogic 12c Admin Console components

Change Center


WebLogic Domain running in Production Mode, the Change Center will be available with two dynamic buttons. This keeps track of who does what and locks when an Administrator performs a session. The console gets locked for that user and can only be changed unless the session has been activated or released. This mechanism prevents other users logging in to the console and doing configuration changes before you are finished.

Domain Structure


you can find a navigation tree called the Domain Structure. In here, you can access all configurable resources within the WebLogic Server, such as:

  • WebLogic Environment contains Server: such as Administration Server, Managed Servers, and Clusters
  • Services: such as JDBC and JMS 
  • Deployments: install, update, deletion of Applications, resource adapters, and Libraries 
  • Security: Providers, Encryption keys, and wallets 
  • Diagnostics and Logging choice for each sub system

System Status

The System Status panel reports on the number of information, error, and warning messages that have been logged. You can view these messages in the server log files, which you can access from the Administration Console at Diagnostics | Log Files.

Breadcrumbs


In the task-bar, you can track your previous navigation using the Breadcrumbs, so you can jump back two or three steps before.

WebLogic Admin Console disable and enable


The admin console can be disabled and enabled. We can disable it using admin console advanced attributes and for enable back We need to use WLST. The context path of the admin console may be changed, to represent which environment it is for example project_DEV or project_FT instead of console. The administration console may be extended with a jar which can be included in DOMAIN_HOME/console-ext directory. If the domain's administration port is enabled, access to the administration console must be made only through that port. Remember that we cannot access with regular port.

One instance of WebLogic Server in each domain is configured as an Administration Server. The Administration Server provides a central point for managing a WebLogic Server domain. All other WebLogic Server instances in a domain are called Managed Servers. In a domain with only a single WebLogic Server instance, that server functions both as Administration Server and Managed Server. The Administration Server hosts the Administration Console, which is a Web application accessible from any supported Web browser with network access to the Administration Server. Managed Servers host applications.

Console Disable or Enable
Steps to disable access to the Administration Console
Admin Console disable from Admin console
WebLogic 12c Admin Console Disabling

  1. After you login to admin console click Lock & Edit if you are in production startup mode. 
  2. In the left pane of the Admin Console, under Domain Structure, select your domain name. 
  3. In the right pane on the work area, Configuration > General, and click 'Advanced' at the bottom of the page. 
  4. You can see by default value is checked for the Console Enabled attribute. 
  5. Finally, Click Save button. 
  6. In production domain, to activate these changes, click Activate Changes button in the change center. 
  7. Restart the Admin server required to see this!!!
Now I've restarted the Admin Server and tried to open the Admin console but it was showing me ERROR 404!!! (as expected)
Admin Console disabled - 404 
Now goto the PuTTY/terminal open your WLST prompt
1. connect to your admin server
2. edit the session change consoleEnable attribute to true which was false!
3. save the changes 

wls:/offline> connect('weblogic','welcome1','t3://183.82.51.70:65001')
Connecting to t3://183.82.51.70:65001 with userid weblogic ...
Successfully connected to Admin Server "devAdmin" that belongs to domain "devDomain".

Warning: An insecure protocol was used to connect to the
server. To ensure on-the-wire security, the SSL port or
Admin port should be used instead.


wls:/devDomain/serverConfig> edit()
Location changed to edit tree. This is a writable tree with
DomainMBean as the root. To make changes you will need to start
an edit session via startEdit().

For more help, use help('edit')
You already have an edit session in progress and hence WLST will
continue with your edit session.

wls:/devDomain/edit !> startEdit()
Starting an edit session ...
Started edit session, please be sure to save and activate your
changes once you are done.
wls:/devDomain/edit !> ls('a')
-rw-   AdminServerName                              devAdmin
-rw-   AdministrationMBeanAuditingEnabled           false
-rw-   AdministrationPort                           9002
-rw-   AdministrationPortEnabled                    false
-rw-   AdministrationProtocol                       t3s
-rw-   ArchiveConfigurationCount                    0
-rw-   ClusterConstraintsEnabled                    false
-rw-   ConfigBackupEnabled                          false
-rw-   ConfigurationAuditType                       none
-rw-   ConfigurationVersion                         12.1.3.0.0
-rw-   ConsoleContextPath                           console
-rw-   ConsoleEnabled                               false
-rw-   ConsoleExtensionDirectory                    console-ext
-rw-   DomainVersion                                12.1.3.0.0
-r--   DynamicallyCreated                           false
-rw-   ExalogicOptimizationsEnabled                 false
-rw-   GuardianEnabled                              false
-r--   Id                                           0
-rw-   InternalAppsDeployOnDemandEnabled            true
-rw-   JavaServiceConsoleEnabled                    false
-rw-   JavaServiceEnabled                           false
-r--   LastModificationTime                         0
-rw-   Name                                         devDomain
-rw-   Notes                                        null
-rw-   Parent                                       null
-rw-   ProductionModeEnabled                        false
-r--   RootDirectory                                /home/wlsadmin/wlsdomains/devDomain
-rw-   ServerMigrationHistorySize                   -1
-rw-   ServiceMigrationHistorySize                  -1
-r--   Type                                         Domain
wls:/devDomain/edit !> cmo.setConsoleEnabled(true)
wls:/devDomain/edit !> save()
Saving all your changes ...
Saved all your changes successfully.
wls:/devDomain/edit !> activate()
Activating all your changes, this may take a while ...
The edit lock associated with this edit session is released
once the activation is completed.

The following non-dynamic attribute(s) have been changed on MBeans
that require server re-start:
MBean Changed : com.bea:Name=devDomain,Type=Domain
Attributes changed : ConsoleEnabled

Activation completed
wls:/devDomain/edit> disconnect()
Disconnected from weblogic server: devAdmin
wls:/offline> 

[wlsadmin@AdminSrv devDomain]$ jps
7360 Server
7595 Jps
 
[wlsadmin@AdminSrv devDomain]$ kill 7360
 
startAdmin.sh
Admin console accessable in the browser!!! When there is most crutial changes are expected in the WebLogic domain some of the financial or banking projects uses this as best practice. While process will be before and after changes would be takes place only using WLST.

Friday 10 April 2015

01.a. Installation of WebLogic Server 12c on Unix and Linux platforms


The beginning of the WebLogic Administration practical work with installation of WebLogic software. Before you began, you must aware per-requisites for installation and also how you can proceed for the installation.  This blog post is specially for newbies who just began learning WebLogic.

Determining supported configurations for WebLogic Server


Software requirements
There are many Java vendors according to your platform you need to select specific Java. every WebLogic release version is publishing a certificate matrix which will tell you what platform versions it support and which JDK version you need to use for WebLogic installation.
  • Sun/Oracle HotSpot JDK
  • Oracle JRockit
  • IBM JVM
  • HP JDK
Example Certificate Matrix Reference
WebLogic 12.1.3 certificate matrix

Hardware Requirements
  • 512 MB RAM
  • 20 GB HDD
  • CPU 300 MHz
  • i3 or above processors Amd

Installation modes

WebLogic server 12c can be installed in two ways
  • Silent mode installation
  • GUI mode installation

WebLogic 12.1.3 silent mode installation on Ubuntu

1. What is silent mode installation? And why?
This is the initial setup required to learn WebLogic Administrator. If you unable to do silently you are unfit for the production environment setup. Silent-mode installation allows us to define an installation configuration only once and then use the configuration to duplicate the installation on many machines. During installation in silent mode, the installation program reads the inputs for desired settings up configuration from an silent response file that you must prepare before beginning the installation. The installation program does not display any configuration options during the installation process. Silent-mode installation works on both Windows and Linux and UNIX systems also.

WebLogic 12c silent mode installation

Major Benefits
  • Less time of execution of the installation process 
  • Cloud-ready platforms use this method most often
  • This process can be used in configuration tools such as chef, puppet etc 
  •  Easy to install in multiple machines/Production environments
  •  No need of X11 or Mouse clicks!!
Java Installation
Step 1: JDK installation

You can download JDK from Oracle Technical Network (OTN)  Link
 We have two choices to install JDK on a Linux platform:
1. Common for any Linux platform: tar.gz file
tar -zxvf /u01/app/software/jdk*.gz

 

2. To install WebLogic Server in silent mode installation first we have to install JDK in the Ubuntu.The alternative in the Ubuntu box as follows:
  1. sudo add-apt-repository ppa:webupd8team/java
  2. sudo apt-get update
  3. sudo apt-get install oracle-java7-installer
Step 2: Setup the Environment variables in file called .bash_profile, assume that your login shell is bash. Modify the JAVA_HOME, MW_HOME according to your installations.

export JAVA_HOME=/usr/lib/jvm/java-7-oracle
export PATH=$PATH:$JAVA_HOME/bin
export MW_HOME=/u01/app/oracle/fmw/oraclehome
export WL_HOME=$MW_HOME/wlserver
export CLASSPATH=$WL_HOME/server/lib/weblogic.jar:.

alias wlst="$MW_HOME/oracle_common/common/bin/wlst.sh"
Step 3:Download WebLogic server 12.1.3 Generic file from download link.

Steps involved in silent mode installation

Step 4: Create a directory “silent” and copy the wls.jar file to this directory. mkdir silent
Step 5: Go to the silent directory by using cd silent/
Step 6: Create a file oraInst.loc file in silent directory as follows as: vi oraInst.loc And insert inventory location and installation group as follow as
Inventory_loc=/u01/app/oracle/silent/oraInventory/
Inst_group=oinstall
Step 7: Create a response file and insert below things in the response file
[ENGINE]
Response File Version=1.0.0.0.0
[GENERIC]
ORACLE_HOME=/u01/app/oracle/fmw
INSTALL_TYPE=WebLogic Server
DECLINE_SECURITY_UPDATES=true
SECURITY_UPDATES_VIA_MYORACLESUPPORT=false

You could edit the ORACLE_HOME as you change versions and also

There could be multiple options for INSTALLATION_TYPE:

  1. WebLogic Server
  2. Coherence
  3. Complete with Examples
  4. Fusion Middleware Infrastructure [Infrastructure domains]
  5. Fusion Middleware Infrastructure with Examples [for Restricted JRF, EM domains]




Step 7: Go to the wls.jar location ie in the silent directory and insert the following command

java -jar /u01/app/software/fmw_12*_wls.jar \
-silent -invPtrLoc /u01/app/oracle/silent/oraInst.loc \
-responseFile /u01/app/oracle/silent/responsefile.rsp


Step 8: Check WebLogic server is installed in mention location or not

Conclusion 


 Easy once you worked on this procedure you can work on SOA, OSB, ADF and any Oracle Fusion Middleware products.
The above work is for 12.1.3 version which is an older version of 12c!

WebLogic 12.2.1.x installation in silent mode

The latest version of 12c is 12.2.1.0.0 lets enjoy the new features of WebLogic on Vagrant box here I have executed the installer without matching the certificate matrix. So two of them are not satisfied

  1. Ubuntu Linux
  2. JDK 1.8.0_51 is expected provided 1.8.0_45 

WHAT IS NOT INCLUDED IN THE QUICK INSTALLER?


- Native JNI libraries for unsupported platforms.
- Samples, non-English console help (can be added by using the WLS supplemental Quick Install)
- Oracle Configuration Manager (OCM) is not included in the Quick installer
- SCA is not included in the Quick Installer
[Source extracted from README.txt file]


To install the Quick installer use the following command:
 java -jar fmw_12.2.1.3.0_wls_quick.jar ORACLE_HOME=/u01/app/oracle/fmw

The output of Quick install command:




To install the generic installer use the following command:
oracle@mydev:/u01/app/software$ java -jar fmw_12*_wls.jar -silent -invPtrLoc /home/oracle/silent/oraInst.loc -response /home/oracle/silent/responsefile.rsp
Launcher log file is /tmp/OraInstall2015-10-30_01-30-57AM/launcher2015-10-30_01-30-57AM.log.
Option "-response" is deprecated; use "-responseFile" instead.
Extracting files................................
Starting Oracle Universal Installer

Checking if CPU speed is above 300 MHz.   Actual 2592.418 MHz    Passed
Checking swap space: must be greater than 512 MB.   Actual 767 MB    Passed
Checking if this platform requires a 64-bit JVM.   Actual 64    Passed (64-bit not required)
Checking temp space: must be greater than 300 MB.   Actual 72517 MB    Passed


Preparing to launch the Oracle Universal Installer from /tmp/OraInstall2015-10-30_01-30-57AM
Log: /tmp/OraInstall2015-10-30_01-30-57AM/install2015-10-30_01-30-57AM.log
Copyright (c) 1996, 2015, Oracle and/or its affiliates. All rights reserved.
Reading response file..
Skipping Software Updates
SEVERE:OUI-10054:Unable to modify the group ownership of the OUI inventory to the requested group name "vagrant". Either the specified group doesnt exist, or the current userid does not belong to that group. If the group exists, you may run the shell script {1} as root to change the group name after installation is complete.
Starting check : CertifiedVersions
sh: 1: /bin/rpm: not found
Check complete. The overall result of this check is: Not executed <<<<
Warning: Check:CertifiedVersions completed with warnings.


Starting check : CheckJDKVersion
Problem: This JDK version was not certified at the time it was made generally available. It may have been certified following general availability.

Recommendation: Check the Supported System Configurations Guide (http://www.oracle.com/technetwork/middleware/ias/downloads/fusion-certification-100350.html) for further details. Press "Next" if you wish to continue.

Expected result: 1.8.0_51
Actual result: 1.8.0_45
Warning: Check:CheckJDKVersion completed with warnings.


Validations are enabled for this session.
Verifying data
Copying Files

...............................................................  38% Done.
...............................................................  76% Done.
.....
Installation in progress (Friday, October 30, 2015 1:32:39 AM UTC)
                                                            79% Done.
Install successful

Linking in progress (Friday, October 30, 2015 1:33:07 AM UTC)
Link successful

Setup in progress (Friday, October 30, 2015 1:33:07 AM UTC)
Setup successful

Saving inventory (Friday, October 30, 2015 1:33:08 AM UTC)
Saving inventory complete

End of install phases.(Friday, October 30, 2015 1:33:08 AM UTC)
Percent Complete : 100

The installation of Oracle Fusion Middleware 12c WebLogic Server and Coherence 12.2.1.0.0 completed successfully.
Logs successfully copied to /home/oracle/oraInventory/logs.
oracle@mydev:/u01/app/software$


 Troubleshoot installation issues


Issue 1: Qucick installation time got the following error
oracle@localhost:~$ java -jar fmw_12.2.1.3.0_wls_quick.jar ORACLE_HOME=/u01/app/oracle/fmw
Error: Unable to access jarfile fmw_12.2.1.3.0_wls_quick.jar

Fix: Check the the path where the "fmw_12.2.1.3.0_wls_quick.jar" available, navigate to the path or provide absolute path.

 * Quiz time


When installing Oracle Weblogic Server 11g with the graphical installer, which three statements are true?
A. You must choose either a typical or a custom installation.
B. You install under Microsoft Windows because the graphical installer is available only for Window C. You may create a new middleware home directory or choose an existing one.
D. You must register for critical security updates.
E. You may install a JDK or choose one that was previously installed.

01.b. WebLogic Evolution


WebLogic Evolution

WebLogic 12c

-WebLogic Current version is 12c it will be in the market up to 2019.
-WebLogic 12c supports the cloud facility.
-WebLogic Server 12c versions
         WebLogic Server 12c Release 3 (12.1.3)
         WebLogic Server 12c Release 2 (12.1.2)
         WebLogic Server 12c Release 1 (12.1.1)

WebLogic 11g

 -WebLogic 11g supports grid computing system. There was a big confusion version numbers for WebLogic 11g.
 -Version from 10.3.1 to 10.3.6 is said to be WebLogic 11g

      • WebLogic Server 11gR1 PS5 (10.3.6)
      • WebLogic Server 11gR1 PS4 (10.3.5)
      • WebLogic Server 11gR1 PS3 (10.3.4)
      • WebLogic Server 11gR1 PS2 (10.3.3)
      • WebLogic Server 11gR1 PS1 (10.3.2)
      • WebLogic Server 11g (10.3.1)

WebLogic 10g -This version of WebLogic is delta period one, which does not have much market share in the enterprise applications. Oracle acquired WebLogic and started merging best features of Oracle Internet Application server (iAS). WebLogic 10g provided concept of JMS module and subdeployments.
      • WebLogic Server 10.3
      • WebLogic Server 10.0

WebLogic 9.2 with MPx


-From this version onwards WebLogic taken over by Oracle company from BEA.
-In 9.x there is option to update an application that is deployed from the admin console. No need to un-install and redeploy
-Side by side deployment is possible in 9x
  • WebLogic Server 9.2
  • WebLogic Server 9.1
  • WebLogic Server 9.0

WebLogic 8x

-It is said to most successful version of Enterprise Application Servers. This version introduced the cross platform communication with SOA (Service oriented architecture) was initiated in this version.
  • WebLogic Server 8.1
( <8x versions are not much using in the current projects)
WebLogic Server 7.0
WebLogic Server 6.1
WebLogic Server 6.0
WebLogic Server 5.1  -First version supporting hot deployment for applications (via command line)WebLogic Server 4.0
WebLogic Tengah 3.1
WebLogic Tengah 3.0.1
WebLogic Tengah 3.0
WebLogic Tengah

WebLogic 12c New features

WebLogic 12c has around 200 new features as mentioned below.
  • Fast swap deployment
  • Maven Plugins
  • Supporting JDK1,6 and above versions
  • SOA web services Ready platform
  • Elastic Cloud



01 WebLogic Overview

What is WebLogic ?

WebLogic is a JEE(Java Enterprise Edition) application server which supports several protocols and services. WebLogic server provides two types of services like static content and dynamic content.
Define WebLogic
What is WebLogic


Dynamic content: Dynamic content requires processing by an application server such as Tomcat, and typically invokes backend services via the SDK. For example, logging on calls the logon.do method, which invokes the Central Management Server (CMS) for the user authorization process? Similarly, viewWebiReport.do engages a Web Intelligence Report Server in order to render a report. -WebLogic Server implements J2EE component technologies and services. J2EE component technologies include servlets, JSP Pages, and Enterprise JavaBeans. J2EE services include access to standard network protocols, database systems, and messaging systems. To build a WebLogic Server application, you must create and assemble components, using the service APIs when necessary.

Components are executed in the WebLogic Server Web container or EJB container. Containers provide the life cycle support and services defined by the J2EE specifications so that the components you build do not have to handle underlying details. Web components provide the presentation logic for browser-based J2EE applications. EJB components encapsulate business objects and processes. Web applications and EJBs are built on J2EE application services, such as JDBC, JMS (Java Messaging Service), and JTA (Java Transaction API).

Static content: Static content are files that don't change based on user input, and they consist of things like JavaScript, Cascading Style Sheets, Images, and HTML files. They comprise the structural components of SAP BI web applications such as BI Launch Pad and the Central Management Console (CMC).

Differences between Webserver and Application Server

upate soon....
WebLogic Server Terminology

WebLogic Domain
WebLogic Domain is the basic administrative unit of WebLogic server. AdminServer, managed servers are defined with in the domain. You must first have a domain to define a WebLogic server cluster. Every domain has one Administration server and 0 or many managed servers could be optional.

Server
A server is a running instance of an application (software) capable of accepting requests from the client and giving responses accordingly. Servers can run on any computer including dedicated computers, which individually are also often referred to as "the server".

Machine
A Machine is the logical representation of the computer that hosts the one or more WebLogic Server instances. WebLogic server uses configured machine names to determine the optimum server  in a cluster to which certain tasks ,such as HTTP session replication ,are delegated. The Administration Server uses the machine definition in conjunction with Node manager to start remote servers.

Cluster
A WebLogic Server cluster consists of multiple WebLogic Server  instances running simultaneously and working together to provide increased scalability and reliability. A cluster appears to clients to be a single WebLogic Server instance. The server instances that constitute a cluster can run on the same machine, or be located on different machines. We can increase a cluster’s capacity by adding additional server instances to the cluster on an existing machine, or We  can add machines to the cluster to host the incremental server instances. Each server instance in a cluster must run the same version of WebLogic Server.


WebLogic Books

  • Oracle WebLogic Server 12c: Administration Handbook
  • WebLogic Diagnostic Framework
  • Advanced WebLogic Server Automation
  • Oracle SOA Suite 11g Administrator's Handbook

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