mWarp: Accelerating Intra-Host Live Container Migration via Memory Warping

Live container migration allows containers to roam from one server to another to achieve agility goals like load balancing, tackling machine failures, scaling in/out and reallocating resources. However, migrating a container is also costly mainly due to memory state migration — a large number of memory pages need to be copied from the source server to the destination server. In this paper, we propose a fast and live container migration approach, mWarp, in an intra-host scenario, where both the source and destination virtual machine (VM) servers reside on the same physical host. Instead of copying a container's memory, mWarp relocates the ownership of the container's physical memory pages from the source VM to the destination VM with a highly-efficient memory remapping mechanism. As relocation of memory ownership is light-weight, mWarp leads to fast and live container migration with less service disruption to applications running in containers being migrated. We implement mWarp upon a well-known live container migration tool (CRIU) with key kernel/hypervisor-level support. The evaluation with both micro benchmarks and real-world applications shows that mWarp greatly reduces the total container migration time and downtime (e.g., by an order of magnitude) with significantly improved application-level performance (e.g., by 20%).