An analysis of the performance of block live migration in Openstack

Since our servers have been set up for live migration with Openstack Icehouse, we wondered how live migration would perform. We measured the duration of the migration process, VM downtime duration and the amount of data transfered via the ethernet during a live migration. All tests were performed across 5 different VM flavors to examine the impact of the flavor. Another point we were curious about is how  higher memory load of VMs can impact migration performance. Here, we present the results of our experiments which show how live mgration works in these different scenarios.

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Setting up Live Migration in Openstack Icehouse [Juno]

[Update 8.12.2014] Since OpenStack’s Juno release hasn’t introduced any changes regarding live migration, Juno users should be able to follow this tutorial as well as the Icehouse users. If you experience any issues let us know. The same setup can be used for newer versions of QEMU and Libvirt as well. Currently we are using QEMU 2.1.5 with Libvirt 1.2.11.

The Green IT theme here in ICCLab is working on monitoring and reducing datacenter energy consumption by leveraging Openstack’s live migration feature. We’ve already experimented a little with live migration in the Havana release (mostly with no luck), but since live migration is touted as one of the new stable features in the Icehouse release, we decided to investigate how it has evolved. This blogpost, largely based on official Openstack documentation, provides step-by-step walkthrough of how to setup and perform virtual machine live migration with servers running the Openstack Icehouse release and KVM/QEMU hypervisor with libvirt.

Virtual machine (VM) live migration is a process, where a VM instance, comprising of its states, memory and emulated devices, is moved from one hypervisor to another with ideally no downtime. It can come handy in many situations such as basic system maintenance, VM consolidation and more complex load management systems designed to reduce data center energy consumption. Continue reading