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IaaS clouds have attracted much attention, and OpenStack has become a de facto standard software for building open-source IaaS clouds. However, the performance and scalability of OpenStack services still have room for improvement. This study focused on the admission control of API requests to improve performance. We revealed the basic effect of admission control by setting the concurrent connection...
Online data-intensive services parallelize query execution across distributed software components. Interactive response time is a priority, so online query executions return answers without waiting for slow running components to finish. However, data from these slow components could lead to better answers. We propose Ubora, an approach to measure the effect of slow running components on the quality...
Service providers must guarantee high quality of service (QoS) for each web application in a data center and simultaneously achieve optimal utilization of their infrastructure. Meeting the Service Level Objectives (SLOs), such as response time in a dynamic environment with a dense load and varying capacity, and simultaneously minimizing the energy consumption of the data center is an open research...
In this paper, a dynamic control method for two-stage queueing systems with process queue time (PQT) constraints is presented. This queueing system consists of an upstream batch process machine and a downstream single process machine. The waiting time of each job in the downstream queue is constrained by an upper limit. Violation of this upper limit causes scrap of the job. A batch machine poses a...
Exploiting the benefits of virtualization, web services are consolidated in large data centers. Managing the performance of such complex systems is a critical problem. Providers must offer applications with high quality of service (QoS) and performance and simultaneously achieve optimal utilization of their infrastructure. Meeting their Service Level Objectives (SLOs), such as response time in a dynamic...
Multi-step ahead response time prediction of CPU constrained computing systems is vital for admission control, overload protection and optimization of resource allocation in these systems. CPU constrained computing systems such as web servers can be modeled as single server queuing systems. These systems are stochastic and nonlinear. Thus, a well-designed nonlinear prediction scheme would be able...
Managing workload for large scale web applications is a fundamental task for satisfactory quality of service, low management and operation cost. In this paper, we present SCOPS, a system of distributed workload management to achieve service differentiation and overload protection in such large scale deployment. Our system splits the workload management logic into distributed components on each back-end...
Managing the performance of virtualized web applications is a critical problem for service providers. Meeting their Service Level Objectives (SLOs), such as response time, in a dynamic environment(dense load, variable capacity), is a challenging task. In this paper, we propose an autonomous scheme for admission control in cloud services aiming at preventing overloading, guaranteeing target response...
This paper discusses our experience in building SPIRE, an autonomic system for service provision. The architecture consists of a set of hosted Web Services subject to QoS constraints, and a certain number of servers used to run session-based traffic. Customers pay for having their jobs run, but require in turn certain quality guarantees: there are different SLAs specifying charges for running jobs...
In previous work we motivated the need for using the OSGi Framework with the RTSJ to develop real-time systems. We found a number of issues with using these technologies together. One of the issues we discovered was unbounded dynamism caused by the absence of admission control. Components can be uninstalled, installed and updated without regulation. This means that it is impossible to guarantee resources...
In three-tiered web applications, some form of admission control is required to ensure that throughput and response times are not significantly harmed during periods of heavy load. We propose Q-Cop, a prototype system for improving admission control decisions that considers a combination of the load on the system, the number of simultaneous queries being executed, the actual mix of queries being executed,...
In this paper, we present Arctic, an adaptive reinforcement learning control technique for Web intrusion check. A rule-based model is designed to describe the requirement of vulnerability detection. The whole validation rule set is divided into multiple sections, and each can be enabled in either in-line control mode or off-line monitoring mode based on the observation and analysis of user behaviors,...
The system capacity available to a multi-tier Web based application is often a dynamic quantity. Most static threshold-based overload control mechanisms are best suited to situations where the system's capacity is constant or the bottleneck resource is known. However, with varying capacity, the admission control mechanism needs to adapt dynamically. We propose and implement an adaptive admission control...
SIP flow management should respect the specific characteristics of SIP protocol applied in multimedia or telecom services for meeting stringent quality of service (QoS) requirement. The specific characteristics include explicit session structure for correlating a series of SIP messages, stringent response time required by real-time applications, extra overhead imposed by SIP message retransmission,...
Parallel transactional systems are systems that execute transaction tasks in multiple servers, with load-balancing. We consider time constraints on those tasks and the fact that the tasks run in milliseconds means that fast admission control should be used. We propose such an admission control approach. Although there are scheduler designs building and maintaining complete deadline feasible schedules...
The Web has become an important medium for access to information and users increasingly depend on it for their routine activities. Hence, the demand for higher quality services has grown strong and overload control has become a key problem to be addressed in Web servers. This paper analyzes the implementation of a fuzzy admission controller in a QoS-enabled Web server architecture and compares its...
In this paper, we study how to build a front-end flow management system for SIP application servers. This is challenging because of some special characteristics of SIP and SIP applications. 1) SIP flows are well organized into sessions. The session structure should be respected when managing SIP flows. 2) SIP has been adopted by telecom industry, whose applications have more critical QoS requirements...
A class of resource location service for distributed VoD system, which combines one-hop k-random walk and global centralized indexing service, is studied. First, in order to minimizing the cost of communication and guaranteeing the response time performance, a Markov model is proposed to describe the queue phenomenon, admission control and the process of location. In this model, control is related...
This paper tackles the problem of autonomic admission control for web clusters. The main contribution of this work is the proposal of a new session admission algorithm that self-configures a dynamic constraint on the rate of incoming new sessions to guarantee the respect of Service Level Agreements (SLA). Unlike other approaches, our policy does not need any prior information on the incoming traffic,...
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