Browsing by Author "Li, Hong-Wei"

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Application Dependency Tracing for Message Oriented Middleware
(2014)
Wu, Li-Juin
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Li, Hong-Wei
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Cheng, Yu-Jui
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Wu, Yu-Sung
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Lin, Houcheng
Software defined infrastructure greatly reduces the deployment cost of distributed applications. Many distributed applications employ message oriented middleware (MOM) for the integration of heterogeneous components and to achieve scalability and fault tolerance. The structure of a distributed application can be very complex. In addition, the asynchronous message delivery model of MOM further complicates the runtime behavior of a distributed application. To diagnose a faulty distributed application, one often needs to determine the dependences of its messages, and by extension, the dependences of its components. We propose Message Tracer to identify the message dependencies of a MOM-based distributed application. Message Tracer sniffs the network traffic of MOM and uses knowledge of message broker protocols to establish the dependencies. Message Tracer makes no assumption on the application threading model and incurs negligible performance overhead. Message Tracer correctly identified 95% of the dependencies for the common use cases and 75% of the dependencies when the system was under extreme stress.
Application Execution Time Prediction for Effective CPU Provisioning in Virtualization Environment
(2017-11-01)
Li, Hong-Wei
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Wu, Yu-Sung
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Chen, Yi-Yung
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Wang, Chieh-Min
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Huang, Yen-Nun
Provisioning of hardware resources through virtual machines (VMs) has been widely used for supporting server consolidation and infrastructure-as-a-cloud computing. We propose NICBLE to support accurate CPU resource provisioning for application workload running on VMs. While CPU is essential for any application workload, not every workload requires the same level of CPU resource. The VM tenants may also have different expectations of application performance and preferences. NICBLE models the execution of an application workload and employs a simulation-based algorithm to predict the impact on application execution time for a hypothetical VM configuration change on the number of CPUs. One may use NICBLE to reason about whether changing the number of CPUs will significantly affect the application performance. We built the NICBLE prototype on top of the Xen hypervisor [1]. NICBLE does not require modification to the guest systems. The performance overhead on the guest system is negligible. Our evaluation indicates that NICBLE is able to provide accurate prediction with an average error rate of less than 15 percent for non-adaptive application workload.
HIT: Hybrid-mode Information Flow Tracking with Taint Semantics Extraction and Replay
(2018-01-01)
Hung, Yu-Hsin
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Li, Hong-Wei
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Wu, Yu-Sung
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Jheng, Bing-Jhong
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Huang, Yen-Nun
Due to increasing complexity in security attacks, it is no longer sufficient to rely on generic network-level and system-level events for attack detection. We propose the hybrid-mode information flow tracking (HIT) system to reveal application-level events by integrating static information analysis (IFA) and dynamic information flow tracking (DIFT) into the applications. Preliminary results indicate the effectiveness of the approach in detecting sensitive data leakage with a modest performance overhead.
Towards Consistent Software Defined Networking with Logic Programming
(2015)
Lui, Eric
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Wu, Yu-Sung
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Ngai, Patrick
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Lin, Tung-Yueh
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Li, Hong-Wei
Software Defined Networking (SDN) allows the construction of virtual networks on top of a datacenter network infrastructure. However, the flexibility also increases the chance of inconsistencies in the network configurations caused by component failures, software bugs, or human errors. The inconsistencies may result in service outage or security policy violation. We propose a model-based verification system to check the consistency of a virtual network. The system models the requirements as logic constraints and extracts the configuration states of a virtual network. The configuration states are checked against the logic constraints by using a SMT solver[1]. The prototype system successfully detects various inconsistencies injected to the testbed and incurs reasonable amount of overheads.