Limit resource utilization on a per-user basis
For fairness, CPU, memory, and I/O (e.g. network and disk) resources should be metered/shaped on a per-user basis. Cgroups have facilities for accounting and limiting resources that should be adequately capable.
This should be done on a per-user rather than per-Chroniton basis, so if user A spins up N Chronitons that fully utilize e.g. CPU, and user B spins up 1 Chroniton that fully utilizes the CPU, user B's Chroniton will get 50% of system CPU, and user A's individual Chronitons will each get 50%/N of system CPU, with 50% total across the set of Chronitons. In non-fully loaded situations, individual users may utilize all spare capacity.
This is easier for CPU utilization, but dynamic memory limits can be more complicated.