Hi , 

To setup high availability for Odoo , it should be nothing different setting it up as any other web server ,but you have to decide ,

what architecture ,

1. web application  + db on same server .

2. web application and db on separate server 

for configuration 1 above , it need at least 4 servers , 2 for load balancer and 2 for web application (odoo) + db (postgres)

for configuration 2 , it needs at least 6 servers , we split the web application (odoo) and db (postgres) into a separate server .

for details of how to do this , there are many good article around , such as How to create a high availability server at Digital Ocean ? And as for the Postgres , you have decide what kind of replication model u desire for you can basically find most of the available postgres replication/clustering wiki.

Hope this give you a good starting point.

Regards,

Kalmen

Hello Kalmen

Thanks a lot for you answer

I wil check the information as you mention

The problem that I have is the carrier service  of internet in the customer area is very bad and for that reason my customer want to install a local server in HA but the price is high vs the solution in the cloud.

Best Regards

Jesus Velazquez