How to use cluster.routing.allocation.allow_rebalance?

Hi,
I am trying to ensure that re-allocation of shards are prevented whenever one of the nodes in the cluster goes down. Based on the documentation I read online, I use the following settings on the cluster

"persistent": {
"cluster.routing.allocation.enable": "none",
"cluster.routing.allocation.disable_allocation":"true"
}

However, this prevents new indices from being allocated as well. This is not OK for me and so my requirement is to be able to do both the following things -

  1. Be able to create indices dynamically.
  2. Prevent re-allocation of shards when a node in the cluster goes down.

Based on the documentation, I understood that setting cluster.routing.allocation.allow_rebalance to "indices_all_active" will do both the things. But this didn't happen. Hence, my understanding is clearly wrong. So what does it mean to set allow_rebalance to indices_all_active ? When going over the mailing list, I also found the concept of "dynamic settings". I assume this means that there are some values that I can set when the cluster is live and some settings that I can only set in the configuration file, which will be set on restarting elastic search. Is allow_rebalance one such setting?
Please correct me if I am on the wrong path altogether.

I see that I have raised multiple questions in one thread. However, all of them are a related use case to me. Can you please advice me on these.

Thanks,