Virtual machine management in data centers is more and more complex due to the increasing total number of virtual machines. Virtual machine resources and scheduled policies (e.g., consolidation) define the virtual machine placement. This placement is difficult to compute for large infrastructures. Administrators maintain a correct placement by performing actions (e.g., migrate virtual machines, power off servers, etc.) and some time using autonomic schedulers. The authors propose btrScript: a safe autonomic system for virtual machine management that includes actions and placement rules. Actions are imperative operations to reconfigure the data center and declarative rules specify the virtual machine placement.