Arista CloudEOS provides optimized routing and security functionality by connecting different enterprise branches, DCs and head office across different geographical regions, zones and sites.  It uses traffic engineering to leverage the best paths across a bunch of dynamic Path Selection( DPS ) tunnels which are used to carry the overlay data traffic. It uses the concept of AVT( Adaptive Virtual Topology) to map any given VRF traffic into a specific subsets of traffic each of which is treated uniformly for the routing/security perspective. 

Cloud HA feature provides active active redundancy between two vEOS router instances running in Cloud such as AWS and

When MLAG peer link goes down, the secondary peer assumes the primary peer is down/dead, and takes over the primary