As the number of companies moving application workloads into public and private clouds mushrooms, live migration becomes a key issue.
The OpenStack Innovation Center (OSIC) benchmark tested live migration to find the best way to move forward with non-impacting cloud maintenance. The team — Ala Raddaoui, Alexandra Settle, John Garbutt and Sarafraj Singh — deployed two 22-node OpenStack clouds using OpenStack-Ansible to test two types of live migration. The tests show that live migration works, both with and without the use of shared storage. You can read details about the test methods and results in a 14-page report they prepared.
“You can use it to avoid the downtime needing to reboot a host for maintenance,” the team states in the report. They recommend that if you decide to empty a host, one live migration at a time works best as it takes shorter time to live migrate the VM and has less impact on VM downtime. The team recommends trying to use shared storage where possible and setting the progress timeout to zero if you’re using a release prior to Newton.
“It’s worth noting we do not have a graph for the number of failed live-migrations, because there were none during these test runs,” the report states. “Initial test runs uncovered some bugs that were fixed upstream in the Ocata branch and backported where applicable. After the bugs were addressed, no failures were found.”
You can download the complete report here: High Availability of Live Migration