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WebLogic Server High Availability Concepts

Gokhan Gungor

Oracle ISV Migration Center Consultant

gokhan.gungor@oracle.com

@gokhangungor1

Partner Hub - ISV Migration Center Team

• Who we Are ISV Migration Center Team is a team of senior technical consultants based in

Eastern and Central Europe and represents Oracle's technical investment for partners.

• Mission Statement Enable partners to rapidly and successfully adopt and implement

Oracle latest technology

• What do we Offer Whether you are selling Oracle technology, building business solutions,

including hosted Internet solutions or providing system integration and implementation

services for Oracle technology, IMC Team can help you succeed.

• How can we assist We offer a wide range of free services for partners such as one2one

assistance, webinars, seminars and hands-on workshops.

ISV Migration Center blog: http://blogs.oracle.com/imc

• http://twitter.com/oracleimc

• http://www.youtube.com/oracleimcteam

• http://www.slideshare.net/oracle_imc_team/

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WebLogic HA Agenda

• WebLogic High Availability Overview

• WebLogic Server Clusters

• Failover and Replication in a Cluster

• Load Balancing

• Demo

• Q&A

Data Failure

Human Error

Hardware

Failure

Site Disaster Software Failure

UNPLANNED DOWNTIME

Failures & Solutions

Backup & Recovery

Clusters

Node Manager

Cluster wide JNDI

Service Migration

WAN Clusters

Disaster Recovery

Clusters

Server Migration

Clusterware Integration

WLS High Availability

Deploy and Re-deploy

Applications

Transformations, scalability

and topology extensions

Upgrades

Configuration

Changes

PLANNED DOWNTIME

Operations & Solutions

Hot Deployment

Side By Side Deployment

•Online Configuration

Changes and warnings

•Batching

changes/Deferred

Activation

•Cluster wide JNDI

•Dynamic Clusters

•Cloning

WLS High Availability

Rolling

cluster upgrade

WebLogic Typical High Availability

Topology

WLS Cluster

WLS Cluster

WLS Cluster Oracle DB

Oracle DB Apache

Server or OHS

Apache

Server or OHS

Node Mgr

Node Mgr Node Mgr

Administration Server

FW-1 LB-1

FW-2

DMZ Intranet

Internet

Node Mgr Desktop

X

X

X

X

WLS Concepts

WLS

Domain

Admin Server

Node Manager

Managed Server

Cluster

Config.xml

Migratable Service

Admin Console

Admin Console

Domain

• What is it? • a logically related group of

WebLogic Server instances that you manage from a single set of configuration artifacts.

• What’s in a domain? • Servers

• Clusters of servers

• Rules: • All WebLogic Server instances

within the same domain must be at the same major and minor version.

config.xml

Server

• What is it?

• A configured instance to host

applications and resources

• WebApps, Enterprise Apps,

Web Services, …

• JMS, JDBC, Diagnostics, …

• What types of servers are

there?

• Administration Server

• Managed Server

JNDI

JMS Queue

JDBC Pool

Administration Server

• What is it? • Configuration controller for the entire domain

• What else does it do? • Hosts the Administration Console

• Enables you to start and stop servers from a central location

• Enables you to migrate servers and services within the domain

• Enables you to deploy applications within the domain

• Guidelines: • There must be exactly one* Administration

Server in domain

• Administration Server controls only one domain.

Admin Server

Managed Servers

config.xml

Admin Console

13

Managed Server

• What is it? • A running instance that hosts

applications and resources needed by those applications - The real work horses in a WebLogic domain

• Each Managed Server is independent of all other Managed Servers in the domain (unless they are in a cluster, defined later)

• You can have as many Managed Servers in a domain as you need

• Individual Managed Servers are typically added for capacity and application isolation

JNDI

JMS Queue

JDBC Pool

Cluster

• A group of Managed Servers running

simultaneously and working together

to provide increased scalability and

reliability

• Scalability: through parallelism

• Reliability/Availability: through

replication and redundancy

• Appears as a single instance to most

clients.

• Enables some advanced features

• Whole Server Migration

• Service Migration, and clustered JMS

destinations.

Cluster 1

Cluster 2

Admin Svr

Introduction What is WebLogic Cluster ?

• Multiple WLS instances running simultaneously and

working together.

• Cluster is part of a WLS domain. A domain can have

multiple clusters.

• Cluster members can run in same machine or be

located on different machines.

• Rolling upgrade of cluster members is supported.

• Clients view a cluster as a single WLS instance.

Introduction Key Benefits of Clustering

• Scalability

• Load Balance

• Even distribution of jobs

• Multiple copies of an object that can do a particular job must

be available

• High-Availability

• Failover

• When a object processing a job becomes unavailable, a copy

of the object elsewhere takes over and finishes the job

Cluster Communication Use of IP Multicast / Unicast

• Each cluster member instance uses multicast or Unicast for • Cluster heartbeats

• Broadcast regular "heartbeat" messages to advertise its availability.

• Maintains list of live cluster members when “heartbeat” is received from a member.

• Cluster-wide JNDI updates

• Announce the availability of clustered objects that are deployed or removed locally.

• Updates local JNDI after receiving announcements for clustered objects from peers.

#1 #2

Session State Replication JSPs and Servlets

Browser

Web

Servers

Servlet

Engines

B A B

C

B C

A

Cluster

Web Cluster WebServer with proxy plug-in

WLS instance

Proxy plugin

WebServer

WebServer

Proxy plugin

WLS instance

WLS instance

•iPlanet/SunOne •Apache •IIS •WLS with HttpCLusterServlet

Cluster

Web Cluster External Load Balancer

WLS instance

Load Balancer

WLS instance

WLS instance

•BigIP from F5 •Alteon from Nortel •Cisco

WLS Clustering Clusterable objects

• Clusterable objects include

• EJB

• JSP

• Servlets

• JDBC

• JMS

Cluster Master Not a Single Point of Failure

• Cluster Master is responsible for monitoring all

servers’ liveness

• What happens when the cluster master fails?

• All servers compete to be the new cluster master

• New cluster master is determined as the server that can write

the cluster master record in the database (DB leasing) or with

the earliest start time (consensus leasing)

• Lease data is available either through replication in memory

or in a database

NM

NM

NM

NM

HA – Failure Scenario with Whole Server Migration

Server 2

Server 4 Server 3

Server 1 Server 4

Node managers start the servers in the cluster

The server with the earliest start time becomes the cluster master

Servers send heartbeats to the cluster master to renew their leases, and the cluster master sends lease table data to other servers in the cluster.

This host fails and then loses its lease to run Server 4.

All hosts compete to get the lease to run Server 4. The cluster master grants the lease to this server and calls the node manager to start the server.

HA with Side by Side Deployment Zero Application Downtime

Newer version of application deployed side-by-side with older version in same JVM

Clients already connected continued to be served by older version

New clients connect to newer version

• Test versions before opening up to users

• Rollback to previous versions • Automatic retirement –

graceful or timeout

Managed WebLogic Server

Single Java VM

Application Version

One

Existing External Client

Connections

New External Client Connections

When Activated

Application Version

Two

Internal Client Connections

Test First in Administrative Mode

Oracle RAC - Multi Data Source

Configuration

Cluster Implementation Roadmap

• Install WebLogic Server

• Create a Clustered Domain

• Configure Node Manager

• Configure Load Balancing (Proxy Plug-Ins)

• Configure Replication Groups

• Configure Clustered JDBC / JMS Resources

• Package Applications for Deployment

• Deploy Applications

• Configure In-Memory HTTP Replication

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attention to a quote from a prominent

customer, executive, or thought leader

in regards to a particular topic.”

• Name • Title, Company Name

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