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=="Starter" Applications (Models)==

Experts at the OpenClovis IDE can brew a complex redundancy model from scratch in just an hour or two. However building a model from scratch is more difficult for a beginner than modifying an existing model. To help new users, the OpenClovis SAFplus Platform provides "starter" models that can be used to begin your model. These are different from the "eval" kit in that the eval kit is made to showcase the features and functionality of the SAFplus Platform and as such are defined to use a very minimal physical (2-3 nodes) layout and simple redundancy model. On the other hand, the "Starter" Models are useful models that you may base your model off of.

The models are located src/examples/ide_workspace (IDE model) and src/examples/ (generated code).

===The "Starter" Application - IP Address Failover - src/examples/virtualIp ===

This starter model implements a commonly-desired feature that is often considered difficult to implement, but becomes very simple on top of the OpenClovis SAFplus Platform infrastructure - IP address failover.

The idea behind IP address failover is to have a "virtual IP" address that can be moved from the active blade to another blade when the active fails. This is an essential component of many highly available network servers.

The Translation into a SAF/OpenClovis model is very simple. Each Virtual IP address is defined as a "Component Service Instance" (CSI), essentially a "work assignment". Each CSI contains the IP Address (e.g. 192.168.1.2) and the physical network interface (e.g. eth0) on which it should be assigned. When the OpenClovis SAFplus Platform "assigns" the CSI to a blade, the software assigns the IP address to the physical network interface using the standard linux "ifconfig" utility. It then issues a "gratituous ARP" to notify the larger network of the IP address change. When the OpenClovis SAFplus Platform "removes" the CSI from a blade, the software removes the IP address from the physical network interface using "ifconfig".

The only custom code needed is the application-specific code needed to bring up an interface and issue the gratituous ARP.

This model can be packaged with the OpenClovis SAFplus Platform or as an application-only deployable bundle (using SAFplus Platform Web Director). To create an application-only bundle, first build SAFplus Platform package normally (i.e. configure; make). Next, go to the "virtualIp/bundle" directory and type "make". An application tarball will be created.

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Senthilk at 04:08, 27 August 2010