Three Reasons Why You Need Volcano

Volcano is a Kubernetes native batch scheduling system. This open-source project is optimized for compute-intensive workloads, and is especially useful in sectors such as AI, big data, genomics, and rendering. Mainstream computing frameworks in these sectors can easily connect to Volcano to integrate high-performance job scheduling, heterogeneous chip management, and job management.

The default scheduler of Kubernetes schedules containers one by one. This can waste resources and result in resource bottlenecks, causing containers to deadlock in scenarios where a group of containers need to be scheduled all at the same time, for example, in AI training jobs or big data applications.

Suppose an AI application consisting of 2 ps containers and 4 worker containers needs to be scheduled onto limited resources. When the default scheduler tries to schedule the last worker container, if there are no resources available, the scheduling fails. The job hangs as the application cannot run without that last worker container. Meanwhile, resources occupied by the already scheduled containers produce nothing.

This is where Volcano comes in. It ensures that a gang of related containers can be scheduled at the same time. If for any reason it is not possible to deploy all of the containers in a gang, Volcano will not schedule that gang. In practice, it is not uncommon for us to deploy a set of internally dependent containers onto limited resources. Volcano is vital in these cases as gang scheduling eliminates potential deadlocks resulting by insufficient resources. Volcano significantly improves resource utilization for heavily loaded clusters.

Leave a Comment