An example of a non-transitory computer-readable medium to store machine-readable instructions to be executed by a processor. The instructions may cause the processor to create a first knowledge graph to represent a computer system at a first time. The first knowledge graph may include a first set of entries to represent a first set of components of the computer system. The instructions may cause the processor to create a second knowledge graph to represent the computer system at a second time after the first time. The instructions may cause the processor to compare the second knowledge graph with the first knowledge graph and perform a corrective action based on the comparison.