Designing a scalable network overlay for Kubernetes multi-cluster topologies

Nowadays, more and more organizations leverage Kubernetes as a way to deploy containerized applications. In addition, they tend to own different clusters in order to increase their geographical reachability or avoid the vendor lock-in, in case of public clouds. Given that, an efficient management of multi-cluster should be crucial in companies. This thesis analyzes the limitations of Liqo when supporting this very important use case. Liqo is an open-source project that enables the creation of multi-cluster environments by making clusters able to offload workloads on ‘peered’ clusters. However, the current version experiences different issues when deploying applications living on more than two clusters: the first deals with the network architecture that does not provide a way of communication between ‘Spoke’ clusters while the second is about how Pods (i.e. Endpoints) are advertised in such clusters. The thesis proposes a new design based on an Hub and Spoke topology coupled with a new logic in the control-plane used to advertise Pods. The result allows Pods in Spoke clusters to talk one to another and Endpoints to be advertised in different ways according to (1) when they are run and (2) where they are going to be advertised.