Project No. 9

1. Project No. 9 Salone Gupta Amartya Dasgupta Syed Eqbal Alam Sneha Maria Joseph Arijit Mitra

2. High Availability??? • A system design that ensures certain degree of operational continuity. • Provides fault tolerance • Provides data reliability Virtual machine migration

3. Virtualization??? • It provides an abstraction layer that allows each physical server to run one or more virtual servers at the same time, decoupling operating systems and applications from the underlying physical server. Benefits: • Maximize resources • Test and development optimization • Reduce business continuity costs • Solve security concerns

4. Goals • Implementation of active and passive servers on a virtual platform • Implementation of a heartbeat mechanism • Implementation of process image transfer for keeping track of data • Implementation of switching mechanism between active and passive servers

5. Client 1 Terminal Server Client Reconnector 3 6 Heartbeat Module 2 5 Physical Machine Physical Machine Active Server • Passive Server Heartbeat Module Heartbeat Module 4 Image Transfer Module Image Transfer Module 7 Virtual Machine Virtual Machine Low Level Architecture

6. Workflow WHEN THE ACTIVE SERVER IS WORKING • The client requests the terminal server. • The terminal server checks the heartbeat signals from the active server. • If the heartbeat signal is ok, the client request is redirected to the active server. • After the request acknowledgement, the active server sends its image and process checkpoint to the passive server at a certain frequency. WHEN THE ACTIVE SERVER FAILS • The terminal server pings the passive server to check its health status and the passive server restarts from the previously received image and process checkpoint. • The terminal server redirects the client to the passive server. • Now the passive server starts behaving as the active server and when the previously failed active server is restored it behaves as a passive server i.e. the roles interchange. • The passive server now sends heartbeat signals to the terminal server to notify its health status. • The passive server sends its image and process checkpoint to the restored active server. On the advent of another failure the steps are repeated and the roles again interchange.

7. Module Description • Image Transfer module – Salone Gupta and Amartya Dasgupta • Creation of image of the server and the process checkpoint associated with a client request • Heartbeat module – Arijit Mitra • Sends or receives a heartbeat signal or ping to notify or to check the health of a server. • Also used to check available passive servers in a passive server cluster. • Client Reconnector – Syed Eqbal and Sneha Joseph • Client connection and redirection to the active and passive servers. • Server Setup – Salone Gupta, Arijit Mitra and Amartya Dasgupta • Setup an active server and a passive server. • Setup a terminal server for client reconnection. • Integration – Team

8. Implementation Plans • Setup of the active, passive and the terminal servers as virtual machines using Xen/Vmware. • Using the heartbeat mechanism, the terminal server checks the status of the other active servers. • Process transfer will be implemented by creating process checkpoints using an open source tool. • On the advent of failure, switching between active and passive servers will controlled by the terminal server.

9. Progress Till Date • Checkpoint creation and restart on single system using an open source tool “BLCR” - Berkeley Lab Checkpoint/Restart • Partial heartbeat implementation

10. Plans Ahead • Deliverables on March 9th,2009 • Virtual server setup • Client connection to the servers

11. References • http://www.ftg.lbl.gov/checkpoint (Berkeley Lab Checkpoint/Restart) • http:// www.ultramonkey.org • http:// www.keepalived.org • Remus virtualization project • http://www.eukhost.com/server-mirroring.php