Live migration

Definition

Live migration refers to the process of moving a running virtual machine (VM) from one physical host to another without disconnecting the client or shutting down the VM. This technique allows for workload balancing, maintenance of hardware, and minimizing downtime while maintaining service availability. Live migration is essential for optimizing resource utilization in environments that rely on hypervisors and virtual machine monitors.

5 Must Know Facts For Your Next Test

1. Live migration minimizes downtime by allowing VMs to continue running while they are being transferred, which is critical for high availability applications.
2. The process typically involves transferring the VM's memory, disk state, and network connections to ensure continuity during the migration.
3. Different techniques exist for live migration, including pre-copy, post-copy, and adaptive methods, each with its own advantages and drawbacks.
4. Live migration can improve load balancing by redistributing workloads across multiple physical hosts in response to changing demands.
5. The successful execution of live migration requires careful management of network bandwidth and storage I/O to ensure performance is not negatively impacted during the transfer.

Review Questions

• How does live migration contribute to workload balancing in a virtualized environment?
  • Live migration allows for dynamic redistribution of virtual machines across different physical hosts based on resource usage and performance metrics. By moving VMs that are consuming too many resources or underperforming to less-loaded hosts, system administrators can optimize resource allocation and enhance overall system performance. This capability ensures that the physical infrastructure operates efficiently and meets application demands without causing downtime.
• Discuss the technical requirements and challenges associated with implementing live migration in hypervisors.
  • Implementing live migration requires robust network infrastructure to handle data transfer between hosts without interrupting service. Key challenges include ensuring adequate bandwidth during migration, maintaining VM state consistency, and addressing potential performance degradation during the process. Administrators must also configure storage access appropriately since disk I/O must be managed seamlessly while the VM continues operations to prevent data loss or corruption.
• Evaluate the impact of live migration on the overall reliability and availability of virtualized services in data centers.
  • Live migration significantly enhances the reliability and availability of virtualized services by allowing maintenance activities without service interruption. It empowers IT teams to perform hardware upgrades or troubleshoot issues on physical hosts without taking VMs offline. This capability not only increases uptime but also supports compliance with service level agreements (SLAs) that demand high availability, making data centers more resilient to hardware failures or peak usage scenarios.

Related terms

Hypervisor: A hypervisor is software that creates and runs virtual machines, allowing multiple operating systems to share a single hardware host.

Virtual Machine Monitor (VMM): A Virtual Machine Monitor is a specialized type of hypervisor that manages virtual machines and allocates resources to them.

Snapshot: A snapshot is a saved state of a virtual machine at a specific point in time, enabling users to revert back to that state if needed.