A key feature of cloud is virtualization, which hides the physical details from users.
Hardware Virtualization
- System virtualization software simulates hardware.
- Supports legacy systems, unusual apps, and multiple OSes.
- Development and deployment environments are the same, avoiding runtime errors.
- Common tools: VMware, Microsoft, XenEnterprise.
- VMs offer:
- Full user control
- Custom OS
- Separation of user environments
- A virtual resource pool is created by virtualization managers.
Virtualization Support in Public Clouds
- AWS: Full VM flexibility.
- GAE (Google App Engine): Limited app-level virtualization.
- Microsoft Azure: Programming-level virtualization (.NET).
- Benefits:
- High availability
- Disaster recovery
- Load leveling
- Rich provisioning
Storage Virtualization for Green Data Centers
- Data centers consume ~3% of U.S. power.
- Green computing is needed.
- Virtualization + server consolidation saves power.
- Fortune 500 companies now adopt energy-efficient policies.
Virtualization for IaaS
Benefits of using VMs in IaaS:
- Server consolidation.
- Run legacy apps without interference.
- Isolated environments increase security.
- Performance isolation improves QoS guarantees.
VM Cloning for Disaster Recovery
Two methods:
- Recover physical machine by another.
- Recover VM using VM cloning.
- Cloning creates backup VMs on remote servers.
- Only one is active; others stay suspended.
- On failure, a snapshot is migrated to the clone.
- Reduces downtime by 60%.
- Live migration is secured, only updating changes.
