ABSTRACT Nowadays, more and more IT services are being hosted on cloud systems, which render cloud systems to grow into a huge complex with millions of physical servers, multi‐layer software stacks and the processing of cloud service requests across many servers and software layers. It is highly demanded for cloud service providers to have the capability of getting the knowledge on cloud service behaviour directly from the service execution instead of from people's expertise. This paper studies the problem of tracing cloud service's processing of requests across components in cloud environments and proposes cloud tracing mechanisms for this purpose. We also developed model‐based studies of our proposed mechanisms for analysing certain designs of the mechanisms. The implementation of the proposed cloud tracing is deployed onto the environments of OpenStack, Kubernetes and Hadoop, and the experiments on these environments demonstrate that our mechanisms effectively trace cloud service behaviour and generate a single complete request execution path, while without our mechanisms the cloud tracing either fails to work or results in thousands of path segments. Our mechanisms have a low performance overhead (2.3%) in the experiments.

IT services are now popularly hosted in cloud systems. In order to enhance the availability of cloud services, an emerging approach for detecting failures of cloud components is to monitor Key Performance Indicators (KPIs) of the components and apply Neural Network based AI technologies to detect KPI anomalies. Multivariate Time Series Anomaly Detection (TSAD) models have been designed for this purpose. However, when applying such models directly to real-world cloud systems the anomaly detection performance is not as good. This is because the number of KPIs in real cloud systems is typically much more than the number of KPIs in the datasets used for model evaluation, and the larger number of KPIs bring about a performance loss of the models’ anomaly detection. Therefore, selecting KPIs properly is essential for applying multivariant KPI data for any practical anomaly detection. This paper studies this performance loss issue when TSAD models are applied onto real-world cloud systems, and proposes fKPISelect, a mechanism of automated KPI selection based on fault injection. We implemented fKPISelect, deployed it to a real cloud system, and created a real-world KPI dataset. We conducted extensive experiments, and the experimental results show the effectiveness and practicality of fKPISelect: it improves the F1 score of anomaly detection from 0.68 to 0.91 for real-world KPI data.

Cloud computing is growingly popular for hosting IT services, and is also growing into a huge complex with millions of physical servers, multi-layer software stacks and the processing of cloud service requests across many servers and software layers. It is highly demanded for cloud service providers to have the capability of getting the knowledge on cloud service behavior directly from the service execution instead of from people's expertise. This paper studies the problem of tracing cloud services' processing of requests across components in cloud environments, and proposes cloud tracing mechanisms for this purpose. The implementation of the proposed cloud tracing is deployed onto an OpenStack cloud environment, and the experiments performed on the cloud environment shows that our mechanisms effectively trace cloud service behavior and generate a single complete request execution path, while without our mechanisms the cloud tracing either could not work or results in thousands of path segments. Our mechanisms' performance overhead is low (2.3%).

The cloud environment is becoming more and more sophisticated as more and more services are running there. Although maintaining the availability of the cloud environment is crucial for cloud service providers (CSPs), the complexity and dynamicity of the cloud network provide difficulties. In this paper, we proposed a mechanism for extracting network knowledge and monitoring network status in the cloud container platform. We deployed our mechanism on OpenShift, a popular cloud container platform, to show its capabilities.