This week we’re attending the Interop conference in New York to present our integrated solution with Citrix Netscaler and XenServer. The solution enables GigaSpaces XAP applications to utilize the Netscaler load balancer AND XenServer infrastructure to dynamically and automatically scale applications (e.g. a standard JEE web app) based on real time application load.
The following screen cast demonstrates how a standard JEE web application (in this case the Spring framework PetClinic demo application) is dynamically scaled on the Citrix SoftLayer cloud.
It runs on a number of virtual hosts which in turn run the Netscaler load balancer, the Web container and the MySql database.
The demo shows how the web application automatically scales out when the load increases. The scale out process includes the following stages:
- The system identifies that the average load has crossed a certain threshold.
- The system dynamically starts a new Xen virtual machine to host a new instance of the web application. This VM includes the GigaSpaces Agent component which enables XAP to dynamically start new JVM to host another web application instance.
- A new web application instance is provisioned to the newly started JVM
- The Netscaler load balancer configuration is automatically updated to reflect the new web container and route traffic to it
- The average load goes back to normal since the traffic is not evenly balanced across the old and new web container.
The demo also shows how the system automatically recovers from a forced virtual machine failure by re-instantiating the virtual machine and the GigaSpaces components on it, and then re-provisioning the missing web application instance onto it.