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Understanding Standby Control and Load Balancing for IBM WebSphere DataPower SOA ApplianceClarissa Brown ([email protected])Daniel Dickerson ([email protected])WebSphere DataPower Support10 August 2010
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Agenda
Standby ControlSelf-Balancing
Load Balancer GroupsIntelligent load distribution
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Standby Group Overview / Configuration
Collection of ethernet interfaces on different appliances that share responsibility for one virtual IP address (VIP)
Basic Requirements:Must be on same network segment
Must be configured with same VIP, group number, and authentication token
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Configuration continued...Restrictions:
Multiple interfaces on an appliance can NOT be defined in the same standby group
MUST be defined with unique priority numbers
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Functionality Operates in active/standby mode
Interface with the highest priority will be the active member
Allows for interface failover to another device
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Eth1 - BoxAIP address: 10.19.0.5/23Priority: 100
Virtual IP address: 10.19.0.1
Eth1 - BoxBIP address: 10.19.0.15/23Priority: 90
Active Passive
Connections
Standby Group Example
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Eth1 - BoxAIP address: 10.19.0.5/23Priority: 100
Virtual IP address: 10.19.0.1
Eth1 - BoxBIP address: 10.19.0.15/23Priority: 90
ActiveDown
Connections
Standby Group Example
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Most Common Problem
Pings or connections to the Virtual IP address (VIP) may timeout or become unresponsive
Problem Symptoms:
Ethernet interfaces switch between Active and Standby state every few seconds
Both interfaces flagged as Active
• Use CLI command 'show standby' to verify active/standby status
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Best Practices to help avoid problem Ensure all basic configuration steps were followed (See DataPower
Administrator's Guide)
Additional configuration tips are recommended:
• Enable Spanning Tree PortFast (or Rapid Spanning Tree) on all switches connected to the DataPower appliances
• Standby group number should be a high value (> 20)
• See Technote 1423478 - Standby Control not working correctly on IBM® WebSphere DataPower SOA Appliance
http://www-01.ibm.com/support/docview.wss?uid=swg21420179
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Self-balancing Overview
Allows two or more DataPower appliances to distribute connections amongst members within a standby group
Requires the Application Optimization (AO) licensed feature
Owner of the VIP (active) is the 'distributor' or 'forwarder' of the connections
If a standby device takes over and becomes active, it becomes the forwarder
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Overview continued... All members in the group learn about all services on each device
Connections are forwarded based on service weights
Service weights can be 0 if the appliance is:running at 100% CPU
lost connectivity (i.e pulled Ethernet cable)
Ports go down
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Enable/Disable Self-Balancing
Must be enabled on ALL devices within the standby group!!
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Self-Balancing Example
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Self-Balanced Service StatusCLI: show self-balanced-status
Local Self-Balanced ServicesCLI: show local-self-balanced-services
Status Examples
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Common Problem All weights are zeroes for services on a standby device
Verify communication between the devices
Verify available resources (cpu, memory)
Ensure all configuration steps recommended for Standby Group are set
Collect packet capture, internal state error report with debug log level, CLI self-balanced status commands
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Agenda
Standby ControlSelf-Balancing
Load Balancer GroupsIntelligent load distribution
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Load Balancer Group Overview / Config
What is a Load Balancer Group for DataPower?
A load balancer group is a server pool that can provide redundancy among a collection of servers.
Used as the remote server to share load across backend servers or as failover support.
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Load Balancer Groups
Load Balancer Algorithms
First alive Hash Least connections Round robin Weighted least connections (AO Only) Weighted round robin
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Load Balancer Groups
Configuration
Under Objects ->
Network ->
Other ->
Load Balancer Group
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Load Balancer Groups
Membership - Static or Dynamic
Static membership
Dynamic membership
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Load Balancer Groups
Adding static members:
Click the Members tab.
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Load Balancer Groups
Health checks
What do health checks accomplish?
What are the 3 Health States?
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Load Balancer Groups
Best practices
Consider the type of traffic
Evaluate tradeoff between speed vs. intelligence
Consider the capacity of the backend
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Load Balancer Groups
Common issues
Health Check failing
Actual Port different than expected
Timeout considerations
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Intelligent load distribution using Option for Application Optimization feature
What is Intelligent Load Distribution?
How do you implement it?
Dynamic Configuration
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Configuration
Install, configure, and start the ODCInfo application on the deployment manager of the WebSphere cell.
Modifying to use workload management
Intelligent load distribution using Option for Application Optimization feature
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Configuration
Weighted least connections
Session AffinityPassiveActive-ConditionalActive
Intelligent load distribution using Option for Application Optimization feature
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Intelligent load distribution using Option for Application Optimization feature
Best practices
Advantages for WebSphere Servers
Advantages for Non-WebSphere servers
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Intelligent load distribution using Option for Application Optimization feature
Common issues
ODCInfo not updating
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Summary
Standby Group & Self-Balancing OverviewConfiguration / Functionality / Example
Common Problem / Solution
Load Balancer Group & Intelligent Load DistributionConcepts / Configuration
Common Issues / Best Practices
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