  With the rapid growth of cloud computing, a variety of software services have
been deployed in the cloud. To ensure the reliability of cloud services, prior
studies focus on failure instance (disk, node, and switch, etc.) prediction.
Once the output of prediction is positive, mitigation actions are taken to
rapidly resolve the underlying failure. According to our real-world practice in
Microsoft Azure, we find that the prediction accuracy may decrease by about 9%
after retraining the models. Considering that the mitigation actions may result
in uncertain positive instances since they cannot be verified after mitigation,
which may introduce more noise while updating the prediction model. To the best
of our knowledge, we are the first to identify this Uncertain Positive Learning
(UPLearning) issue in the real-world cloud failure prediction scenario. To
tackle this problem, we design an Uncertain Positive Learning Risk Estimator
(Uptake) approach. Using two real-world datasets of disk failure prediction and
conducting node prediction experiments in Microsoft Azure, which is a top-tier
cloud provider that serves millions of users, we demonstrate Uptake can
significantly improve the failure prediction accuracy by 5% on average.
