1. A managing server system comprising: at least one communication device to communicate with plural managed nodes that comprise non-transitory computer-readable storage media encoded with plural test executables for running on the respective plural managed nodes for checking configuration data of the respective managed nodes, the configuration data indicating for each respective managed node of the plural managed nodes, a hardware configuration for the respective managed node, an external storage unit accessible by the respective managed node, and software installed on or software accessible by the respective managed node; and at least one processor to: command the test executables to execute concurrently on the plural managed nodes, collect test results returned by the test executables in response to the commanding, the test results including the configuration data of the plural managed nodes, determine based on the test results whether a first managed node of the plural managed nodes is a suitable fail-over target for an application that was executing on a second managed node of the plural managed nodes; and in response to the determining indicating that the first managed node is a suitable fail-over target for the application, cause execution of an instance of the application on the first managed node responsive to detecting failure of the second managed node.