I have consulted the official document but I haven’t found the minimal hardware requirements ( number of node , cpu core , memory , disk io ) for a production environment with or without high availability .
So this is my question .
Thanks for any answer
Hi @c.tamietto 
Welcome to the OpenNebula Forum! 
One of the advantages of OpenNebula is that it uses very few resources to run, so you can really run it almost anywhere! (In fact I run it locally on a Raspberry Pi for my personal home server 
).
In case you need some guidelines, you can refer to this documentation page where the hardware requirements for deploying a VM on AWS to host the OpenNebula server are discussed.
Best,
Victor.