Live migration is a crucial feature in virtualization that allows you to move running virtual machines (VMs) from one physical host to another without any noticeable downtime. This process ensures high availability, load balancing, and efficient resource utilization. In this comprehensive guide, we’ll walk you through the process of performing live migration using the virsh command-line tool and the libvirt virtualization API.
Prerequisites
Before diving into the live migration process, ensure that you have the following prerequisites in place:
- Virtualization Environment: Set up a virtualization environment using a hypervisor such as KVM (Kernel-based Virtual Machine).
- Multiple Hosts: Have at least two physical hosts within the same network that are part of your virtualization cluster.
- Shared Storage: Utilize shared storage accessible by both hosts. This can be achieved using technologies like NFS, iSCSI, or shared network file systems.
Step 1: Verify Compatibility and Configuration
Start by confirming that your hardware, hypervisor versions, and network configuration support live migration. Ensure that both hosts have the same CPU architecture and feature sets. Check if the hosts are part of the same network and can communicate with each other.
Step 2: Prepare Shared Storage
For successful live migration, the VM’s disk images should be accessible from both hosts. Set up shared storage and ensure proper permissions and access rights to the storage resources.
Sub-Step: Export VM Definition
Export the VM definition from the source host using virsh dumpxml and save it to a file. This XML file will contain all the necessary configuration settings of the VM.
Step 3: Perform Live Migration
Execute the live migration process using the virsh migrate command. Specify the target host, transport method, and other relevant options.
Sub-Step: Monitor the Migration
Use virsh or other monitoring tools to keep an eye on the live migration progress. You can track the status of the migration and any potential errors.
Step 4: Verify Successful Migration
After the migration is complete, ensure that the VM is up and running on the target host. Validate network connectivity, resource allocation, and overall VM functionality.
Step 5: Clean Up
Once you’ve confirmed the successful migration, you can clean up any temporary files or configurations created during the migration process.
Conclusion
Live migration is a powerful tool for maintaining the availability and efficiency of your virtualized infrastructure. By following this step-by-step guide, you’ve learned how to perform live migration using the virsh command-line tool and libvirt API. Remember that live migration involves careful planning, compatibility checks, and monitoring to ensure a smooth transition of your virtual machines between hosts.
