Create and configure ODRs
The on demand router (ODR) is an intelligent HTTP and SIP proxy server used as a point of entry into an Intelligent Management environment. An ODR is a gateway through which HTTP requests and SIP messages flow to back-end application servers. We can configure the ODR to determine how it handles failure scenarios and how it tunes certain work requests.
As an alternative gateway into Intelligent Management, WAS ND v9 supports a subset of ODR functions in an Apache or IBM HTTP web server plug-in.
The ODR can queue requests for less important applications, allowing requests from more important applications to be handled more quickly or to protect back-end application servers from being overloaded. The ODR is aware of the current location of a dynamic cluster instance so that requests can be routed to the correct endpoint. The ODR can also dynamically adjust the amount of traffic sent to each individual server instance based on process utilization and response times. The ODR performs Weighted Least Outstanding Request (WLOR) load balancing for selecting a server within a cluster when there is no affinity or when affinity is broken.
By default, the ODR binds to ports 80 and 443 for listening on HTTP and HTTPS, which requires running the ODR as a root user. To run the ODR as a non-root user, change the PROXY listening ports to values greater than 1024.
By default, if no rules are specified in the ODR Routing policy HTTP rules section, all the requested contexts are accepted and are routed to the backend application servers within the cell.
The ODR is aware of the dynamic state of the cell, so that if one server in the cell fails, the requests are routed to another server. When the ODR is notified that the application has initialized on the restarted server, the ODR routes requests to that server again.
The ODR does not route any requests to the application on the application server until the application completes starting or initializing. If the application is started on other application servers, then the requests are routed to them. If the application is not started on any other servers, then the ODR still does not route to the starting-in-progress application server. Instead, a 503 message is returned.
The configuration of the ODR in the DMZ is not supported.
SIP is not supported on the z/OS operating system.
The SIP ODR is stabilized, and is currently not recommended. Use the SIP proxy server instead.
- Create ODRs
- Configure ODRs
- How to configure Intelligent Routing Feature in Websphere Application Server
- Intelligent Management: on demand router system and custom properties
- Configure an ODR to dynamically update the web server plug-in configuration
- Enable cell affinity - ODR
- Use the binary trace facility
- Tune the on demand router (ODR)
- Configure ODR custom logs
- Configure SSL offload for all HTTPS traffic
- Configure SSL offload for partial HTTPS traffic
- Integrate the SIP on demand router with Load Balancer
- Define a service policy
- Intelligent Management: rules for ODR routing policy administrative tasks
- Intelligent Management: rules for ODR service policy administrative tasks
- Intelligent Management: service policy custom properties
- BBSON bulletin board
- Topology Configurations for Multi-Cell Routing
- Generate the plug-in configuration in a high availability environment
- Segregate HTTP traffic by ODR clusters
- Configure passive HTTP session affinity in the on demand router
- Configure the ODR for multi-cluster failover and load balancing routing
- Configure ODR OutOfMemory prevention
- Intelligent Management: controlling the generation of plugin-cfg.xml
- Configure a Web server as a trusted proxy server
- Routing requests directly from a web server to a back-end application server
Web server Tasks :
Intelligent Management for IHS Web Servers Configure Intelligent Management for web servers
Overview of request flow prioritization Set up Intelligent Management for dynamic operations Define routing policies for generic server clusters Define service policies for generic server clusters Add middleware servers to configurations Create dynamic clusters createodr.jacl script Proxy server settings SIP proxy server Propagating plugin-cfg.xml to web servers propagatePluginCfg.py script