Agree responsibility before configuration begins
The decision should account for server capacity, database administration, backup, patching, monitoring, certificate management, recovery objectives and support access—not only where the application files reside.
Write down what each side owns
Hybrid can design implementation responsibilities around the customer’s approved infrastructure boundary. The customer retains responsibility for items assigned to its environment unless the contract states otherwise.
Before commitment: This website explains the approach. The accepted project documents define infrastructure ownership, service levels, security requirements, migration depth, integrations, support and acceptance criteria.