>Is is the cluster that is conscious? Or the individual machines, or the chips, or the algorithm, or something else?

The bound informational dynamic that supervenes on the activity of the individual units in the cluster. What people typically miss is that the algorithm when engaged in a computing substrate is not just inert symbols, but an active, potent causal/dynamical structure. Information flows as modulated signals to and from each component and these signals are integrated such that the characteristic property of the aggregate signal is maintained. This binding of signals by the active interplay of component signals from the distributed components realizes the singular identity. If there is consciousness here, it is in this construct.