Sorry i am new in elastic and i didnt find my question, what happen if i only have one node and the size of my indices are small. Can i put 0 shards? i mean i didnt see the reason to put more, because if i put one is like have only a copy of the index?
Which is the minimum number of shards that i can have?
I believe you mean replica shards and, yes, you can specify zero replica shards for an index. It is a dynamic setting so you can set "number_of_replicas": 0 both for an existing index, using the Update Indices Settings) API, and in the Index Templates for new indices.
In your case, with just one node, you can't have replica shards anyway, as they will just end up unassigned so you really should set number_of_replicas to 0.