Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for monitoring performance deviations. In some implementations, a workflow that is configured to monitor performance of an operation of one or more computers is run. In running the workflow, a performance measure for the operation is determined. In running the workflow, a reference performance level for the operation is determined. In running the workflow, it is determined whether the performance measure indicates a deviation from the reference performance level for the operation. In running the workflow, an action specified by the workflow is selectively performed based on whether the performance measure is determined to indicate a deviation from the reference performance level for the operation.