基于容器云、微服务的综合平台应用实践

随着信息技术的发展,信息系统面临功能扩展灵活、使用场景多变等新挑战,传统的单体应用存在功能耦合强、启动速度慢、弹性扩展难等缺点,难以满足需求;针对此问题,采用微服务架构将大型单体应用拆分为可独立部署的微服务组件;采用容器云对微服务进行编排,实现微服务的弹性扩容、柔性重组。实践表明,基于容器云、微服务的综合平台能够保障信息系统的平稳运行、弹性扩展、柔性重组,满足信息系统的使用需求。     

面向服务的柔性迁移工作流停靠站设计

在迁移工作流系统中,停靠站服务器是迁移实例的运行支撑平台,必须能够支持多种支撑服务和应用服务的集成,适应运行环境和应用需求的动态变化。基于面向服务的概念,提出了一个可扩展、可定制和可重配置的停靠站服务器结构模型,描述了模型的体系结构和内核结构,讨论了服务组件的集成框架和组织模式,以及应用服务的部署模式等,并结合微内核和组件技术给出了参考实现方案。     

基于模板的云应用部署引擎设计

Web应用从物理机部署到云平台的过程中步骤复杂、易于出错并难以自动实现弹性伸缩。针对这种情况,提出一种基于模板的云应用部署引擎设计。通过预定义模板将Web应用所依赖的软件环境和配置进行封装,可支持云环境下应用部署及弹性伸缩的自动化。并基于该设计实现了应用部署引擎。实验结果表明,云环境下应用部署的流程得到简化,部署所需时间大幅减少。该方法能显著地提高云应用部署的效率及质量。     

动态配置机制及其在水利信息系统中的应用

动态配置是指在软件系统运行时动态地改变系统的配置项。基于构件的软件系统配置项涉及系统的构件组成、构件间的连接关系和构件的物理分布。根据支持软件系统动态配置的反射体系结构,建立了动态配置模型,分析了动态配置模型的构成要素,定义了动态配置模型的元数据,以保障运行时系统一致性为基础,构造了动态配置模型的元协议。最后,通过实例,分析了所提出的动态配置机制在水利信息系统软件功能动态配置中的应用。实践表明,基于反射的系统动态配置模型及其实现机制,能在水利信息系统中有效应用,为解决水利信息系统的资源动态配置、支持动态需求等问题,提供了可行的技术方案。     

基于面向服务架构的分布式业务部署平台

针对分布式环境下业务系统运营中资源利用率低、可靠性差和扩展性弱等问题,设计了一种基于面向服务架构的分布式业务部署平台。该平台基于面向服务架构(SOA)组件模型,可自动化地部署和管理分布式业务系统;根据服务组件运行状态,动态为其分配计算资源,实现业务能力的动态扩展和收缩;同时,采用双机热备、高可用集群机、业务迁移等机制保证了高可靠性。仿真实验表明,该平台能在保证业务服务质量(QoS)的同时具有较高资源利用率。     

基于在线实例配置的服务功能链部署方法

为应对实际环境中网络流量的动态变化,同时降低运营商的运营成本,提出基于在线服务功能扩展的服务功能链部署方法。将空置状态虚拟功能实例的生命周期管理问题建模为雪橇租赁模型,采用雪橇租赁问题的最优解配置空置服务功能实例的生命周期,并设计自适应扩展开销最小化的在线服务功能实例扩展算法。以服务功能实例自适应扩展的结果作为约束条件,将每一时刻的服务功能链部署问题建模为整数线性规划问题,利用遗传算法求解带宽开销最小化的服务功能路径,实现动态场景下的服务功能链部署。仿真结果表明,该方法能根据网络流量变化动态调整虚拟资源,降低服务功能实例自适应扩展成本,节省带宽资源。     

软件动态配置模型中的构件依赖描述

构件间的依赖关系是当前基于构件的分布式软件的研究热点之一.提出一种基于XML的描述构件间依赖的方法,并将该方法应用于一个动态配置分布式软件的模型中,成功地实现了构件的动态配置和部署,证明了该方法的可行性.     

支持服务行为和质量的面向服务软件开发

面向服务的软件开发方法减少了开发应用程序的时间和复杂度。当前面向服务架构中的服务注册和发现主要关注于服务的接口描述和静态属性,却较少考虑服务行为和服务质量。对服务行为即外部可见的操作序列的忽视,可能导致服务产生运行时的异常和错误;忽视服务质量即其运行时的质量信息,则可能导致系统运行的低效。本文提出了一种扩展的面向服务的软件开发过程,探宄服务交互过程中其行为一致和质量匹配。在面向服务的组件模型OSGi平台上,采用动态AOP技术,设计了一种支持服务行为和服务质量的中间件系统。该系统不但保证服务发现的调用一致性和服务替换的观察一致性,而且支持对服务运行时操作行为的检测和服务质量信息的收集,从而保证选择最佳的服务实现,提高应用系统的运行效率。     

基于分布式环境一种动态依赖关系发现的方法

本文提出了一种为分布式应用动态构造依赖性模型的方法。这个方法通过对系统进行主动干扰来获得建模的先验知识,然后基于贝叶斯网络构造方法,对分布式应用的组件间关系建立依赖性模型。和传统的被动建模技术不同的是,这种主动方法不需要事先对系统细节充分了解,它通过在运行环境中部署探针,捕捉和测量与部署的主动干扰相关的系统反馈,通过机器学习的方法识别分布式应用中构件间的动态调用的依赖关系,为分布式应用建立动态运行过程中的依赖性模型。动态建立的依赖性模型可用于分布式应用的运行时管理,用于分布式应用执行过程中的故障定位和恢复,对于分布式应用自主计算环境的实现,提供一种实用的方法。     

微服务应用系统迁移上云改造模型

针对当前电网信息通信运维系统存在硬件平台超期服役,信息处理任务无法快速完成等问题,本文提出一种基于Spring Could框架的微服务应用系统迁移上云改造模型,将电网信息通信运维系统迁移至云平台,模型针对集中式系统迁移上云后转变为分布式系统后出现的管理问题,将系统服务全部迁入EDAS体系,实现一键部署、弹性伸缩、灰度发布以及故障自愈.此外,针对系统上云过程中数据量庞大的一致性校验问题,设计了一种基于吉布斯采样的数据一致性采样校验方法,提高了数据一致性校验的效率,减少了系统上云工作量.之后通过国网安徽电力SG-I6000微服务系统上云的实际案例,证明了系统的成功上云和可靠运行.     

体系结构动态演化中的构件行为分析

在体系结构演化的过程中,关闭运行时系统升级的代价增高和频繁改变的业务需求使得研究者考虑动态的软件升级机制.但在体系结构的动态升级过程中,由于构件风格、功能及交互方式等方面的差别,强制的构件升级会影响系统的稳定性和正确性。从构件行为的角度考虑,采用基于Wright的软件体系结构描述语言和通信顺序进程中对于进程的描述方法,描述构件行为并在构件替换之前分析原构件和新构件间的行为特性,在演化前确认构件的行为一致性,从而保证动态升级过程的正确性和合法性,以及提高系统演化的自适应性。     

支持EJB动态分布的组件迁移模型与算法

Web应用服务器是Web计算环境下的新型中间件,为基于组件的分布式Web应用提供了基础运行平台.组件静态分布限制了事务性Web应用在运行期间适应执行环境变化的能力.为了满足Web应用的动态分布需求,Web应用服务器需在底层为组件提供一种动态迁移的能力.如何维持组件迁移前后的一致性是组件迁移中最棘手的问题之一.为解决此问题,定义了组件迁移一致性约束CMC(component migration constrains),并给出了在J2EE(Java 2 platform enterpnse edition)应用服务器中支持EJB(enterprise Java Bean)动态分布的组件迁移模型和SLB Copy,SFB_Copy,EB_Copy 3个迁移算法.分析得出SLB_Copy,SFB_Copy和EB_Copy均满足CMC约束.迁移模型和算法已在自主研制的Web应用服务器WebFrame2.0中实现,并已应用到自适应负载平衡、失效恢复等多个方面.     

基于Docker技术的GUI应用的在线迁移研究

GUI应用在桌面环境中占据主流,在线迁移GUI应用能够提升用户体验.然而,当今广泛使用的X窗口系统所定义的协议十分复杂,不利于GUI进程的在线迁移.另外,如果两台机器的运行时环境不一致,将会导致迁移失败.因此至今未有实现GUI应用的在线迁移.近年来,Wayland作为新的图形接口协议面世,其中规定软件图形渲染由GUI客户端负责,这为迁移工作带来极大的便利.而当今热门的Docker容器技术则能把Wayland GUI应用及其运行时库打包,确保运行时环境的一致性.当迁移发生时,整个容器都会被迁移至目标机器继续运行.本文开发了相应的处理Wayland协议模块,并在CRIU工具的基础上实现了重建Wayland状态.通过实验证明,本文方案是可行的,容易推广到其他的GUI应用.     

基于适配的服务协作流程动态管理

服务协作以服务为构造单元,通过组合不同的服务,实现复杂的业务逻辑,并以此为基础构建新的应用.为实现正确的服务协作,服务之间的交互必须是兼容且一致的.适配技术通过构造适配器来弥补服务之间的交互差异,为解决协作的一致性问题提供了有效的方法途径.然而考虑到服务计算环境的动态特性,协作适配器本身应具有动态调整及重新配置的能力,从而避免使其成为协作系统响应动态变化的可适应能力的瓶颈.文中首先给出了一种基于适配的服务协作方法,以保证服务交互的一致性.并针对提出的适配器结构,建立了适配器的执行模型,在此基础上给出了适配器的动态更新方法,使适配器具有可重配置以及动态调整的能力,从而保证了基于适配的服务协作系统的灵活性和动态可适应性.     

基于CORBA的自适应系统实现

针对自适应系统在运行过程中的状态一致性问题,基于公共对象请求代理体系结构(CORBA)规范,提出一种总线消息型的自适应系统实现方法。该方法以构件组装模型为核心,利用总线对运行时的构件进行状态侦测及重配置操作,使用事务处理机制解决CORBA系统的状态一致性问题,使系统可在运行时修改自身行为。在Java/C++复合构件组装工具上的实现结果验证该方法的正确性,并表明其具备较好的稳定性和自适应能力。     

Human exploration and development of space: using XML database Space Wide Web: Space Wide Web by adapters in distributed systems configuration from reusable components

Human exploration and development of space will involve opening the space frontier by exploring, using and enabling the development of space through information technology, while expanding the human experience into the far reaches of space. At that point in time we assert that the current primitive World Wide Web (Web) will be replaced and dramatically expanded into an Interstellar Space Wide Web (SWW). The current state-of-the-art low-orbits communications satellites constellations will be dramatically expanded to higher orbits and to orbits supporting work on other remote human colonies. This will be necessary in order to furnish in a human-friendly way the necessary software and information that will be needed in support of Interstellar Space Wide Information Technologies. Many of the problems encountered in conceiving of, modeling, designing and deploying such a facility will be different from those problems encountered in today’s Web. Future research and development work will be to identify some of these problems and to conceptually model a few of their solutions. In this work we describe research into the development of scalable tools and techniques that reduce the effort associated with component integration, both with respect to network environments and with respect to other components within the application. Our approach is also targeted at increasing the reusability of software components and software architectures. Our research is to investigate current problems in leveraging adapters as a means to configure of large-scale Next Generation distributed systems software from reusable architectures and components. Our approach to solving this problem is through the development of a novel configuration model and network-aware runtime environment called SWWACXML, for Space Wide Web Adapter Configuration eXtensible Markup Language. SWWACXML provides support for cross-layer architectural configuration at both the application level and the level of individual network connections. The language associated with this environment captures component interaction properties and network level quality-of-service (QoS) constraints. Adapters will be generated automatically from SWWACXML specifications. These adapters are part of the SWWACXML runtime system. The runtime system includes facilities for automatic configuration and runtime reconfiguration, as well as efficient management of network connections and QoS options. This facilitates reuse because components are not tied to interactions or environments. Another aspect of this work will focus on development and experimentation with a novel Web-based interaction paradigm that allows client adapters to tailor themselves to servers at runtime. One of the strengths of our approach is that clients do not have to be tied to specific servers at implementation time. Rather, a client’s adapter loads an SWWACXML configuration page from the server. The SWWACXML configuration page defines the appropriate interaction, including management of heterogeneous network QoS options. We believe our approach is amenable to facilitate a style of dynamic reconfiguration, where clients can at runtime change server, communication or interaction protocol. Future researchers and developers will design and implement the SWWACXML system in a distributed test-bed. They will develop performance analysis techniques to judge the success and efficiency of our approach.     

On constructing communication protocols from component-based service specifications

Constructing communication protocols from component service specifications, each of which specifies a subfunction of the target protocol, enables efficient development of a large and complex communication protocol. Concerning this construction, related techniques have been already proposed: integration of component protocol specifications into a single protocol specification and transformation of service specifications to protocol specifications. However, the integration needs special knowledge of communication protocols, and the transformation requires that a large and complex service specification should be developed as input to produce the target protocol. In order to cope with these problems, this paper proposes a new method which at first integrates component service specifications into a single service specification, and then transforms the service specification into the target protocol by a protocol synthesis technique. The most important point of view is that component integration is performed at the service specification level rather than the protocol specification level. Additionally, we define a class of ‘well-formed’ service specification which ensures correctness of the target protocol. As a result, the integration and transformation can be efficiently executed in small state space without special knowledge of communication protocols. Finally, we have shown the effectiveness of the proposed method by constructing a part of the real-life OSI protocol FTAM.     

QoS aggregation for service orchestrations based on workflow pattern rules and MCDM method: evaluation at design time and runtime

Service consumers satisfaction is considered today as one of the main concern to be ensured by service providers, especially with the spread of concurrency and the increase of functionally equivalent services. This satisfaction is closely related to quality of service (QoS) perceived by service consumers. In this context, we propose an approach to determine the satisfaction degree corresponding to the QoS of service-based applications, with regard to service consumers’ QoS expectations. Our approach is based on a preference model, which is built only on the basis of service consumer’s provided information. This preference model is also based on the 2-additive Choquet operator that takes into account preferential dependencies. In this paper, we target both design time and runtime aggregation of QoS of service-based applications.     

The PEPPHER composition tool: performance-aware composition for GPU-based systems

The PEPPHER (EU FP7 project) component model defines the notion of component, interface and meta-data for homogeneous and heterogeneous parallel systems. In this paper, we describe and evaluate the PEPPHER composition tool, which explores the application’s components and their implementation variants, generates the necessary low-level code that interacts with the runtime system, and coordinates the native compilation and linking of the various code units to compose the overall application code to optimize performance. We discuss the concept of smart containers and its benefits for reducing dispatch overhead, exploiting implicit parallelism across component invocations and runtime optimization of data transfers. In an experimental evaluation with several applications, we demonstrate that the composition tool provides a high-level programming front-end while effectively utilizing the task-based PEPPHER runtime system (StarPU) underneath for different usage scenarios on GPU-based systems.     

A conceptual model of service customization and its implementation

With the development of Internet and next generation networks in telecommunications, more and more new services are required to be introduced into networks. Introducing new services into traditional network is always associated with standardizing new protocols. The progress of protocol standardization usually takes several years, which cannot meet the increasing demands of the applications in Internet and next generation networks. Service customization in network systems may be one possible solution to cope with this problem. Based on the principle that network service is provided by interactions among protocol entities, this paper proposes a conceptual model of service customization (SECUM) by separating the service logic from protocol interactive logic within existing network architecture. The theory of Communicating Sequential Processes (CSP) is used to formalize the SECUM in order to locate exactly the service logic and to define precisely the SECUM. For validating the SECUM‘s usability in practical network systems, this paper also proposes an implementation model for SECUM: a component-based protocol implementation model (CPIM). CPIM discomposes protocol entity into application component, service component, message component and communication component. Service component associates application component with message component. Users or network managers can customize network services by configuring service component. The paper shows respectively the applications of SECUM and CPIM by proposing a customizable IP service model based on SECUM and describing an implementation of Session Initiation Protocol (SIP) based on CPIM. Compared with the existing service-customization techniques, SECUM is a service customization model internal to network system and may provide more powerful capabilities of service customization.