Date post: | 13-May-2015 |
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Technology |
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WebLogic Server High Availability Concepts
Gokhan Gungor
Oracle ISV Migration Center Consultant
@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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customer, executive, or thought leader
in regards to a particular topic.”
• Name • Title, Company Name
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