Now all data loading happens in the TopoViz component as well as
computation of resource proportions.
Allocation selection state is also managed centrally uses a dedicated
structure indexed by group key (job id and task group name). This way
allocations don't need to be scanned at the node level, which is O(n) at
the best (assuming no ember overhead on recomputes).
- Plot all datacenters
- For each datacenter, plot all nodes
- For each node, plot all allocations by memory and cpu
- For empty nodes, highlight the emptiness
- When hovering over allocations, give them visual focus
