Cloud Datacenter SDN Monitoring: Experiences and Challenges

Cloud customers require highly reliable and performant leased
datacenter infrastructure to deliver quality service for their users.
It is thus critical for cloud providers to quickly detect and mitigate
infrastructure faults. While much is known about managing faults
that arise in the datacenter physical infrastructure (i.e., network
and server equipment), comparatively little has been published
regarding management of the logical overlay networks frequently
employed to provide strong isolation in multi-tenant datacenters.
We present a first look into the nuances of monitoring these
“virtualized” networks through the lens of a large cloud provider.
We describe challenges to building cloud-based fault monitoring
systems, and use the output of a production system to illuminate
how virtualization impacts multi-tenant datacenter fault management.
We show that interactions between the virtualization, tenant
software, and lower layers of the network fabric both simplify and
complicate different aspects of fault detection and diagnosis efforts.