Automated AMF Configuration Difference Generation

Many domains require computer clusters to meet clients’ service level expectations. As cluster size increases, component failure becomes more likely. Rapid failure recovery is required to maintain high availability. The SA Forum has created specifications enabling management of multi-vendor solutions. These long-lived systems require tailored upgrade campaigns to keep their configuration up-to-date. Passed works on SA Forum’s Availability Management Framework (AMF) have created an automated AMF configuration generator and upgrade campaign generator. However, to generate an upgrade campaign for an already configured cluster based on a new target configuration, a configuration difference generator is needed. Furthermore, while Distinguished Names (DNs) usually uniquely identify object in a configuration, configuration generators do not guarantee that DNs in the new configuration will match. DN modification is not possible in a system without object replacement, causing service loss. Non-DN based inter-configuration object association is needed to restore old DNs. Our objective is to devise a technique to perform difference generation with limited knowledge of DNs and to find what data is needed to achieve this. To accomplish this, we analyse the AMF configuration model, then propose assumptions in a top down approach based on maintaining service availability during upgrade. We propose a two phase technique that first associates objects in-between configurations and then outputs the differences. We have implemented a tool that implements this technique on the Eclipse Platform and integrates with MAGIC’s Automated Upgrade Campaign Generator. We then present a case study based on the PHASE example

A Model Based Framework for Service Availability Management

High availability of services is an important requirement in several domains, including mission critical systems. The Service Availability Forum (SA Forum) is a consortium of telecommunications and computing companies that defines standard middleware solutions for high availability. Availability Management Framework (AMF) manages the high availability of services by coordinating their application components according to redundancy models. To protect these services, AMF requires a configuration, i.e. a representation of the organization of the logical entities composing an application under its control. AMF configuration design is error-prone and tedious if done manually, due to the complexity of the AMF domain. This PhD thesis explores the effective design and analysis of AMF configurations, proposing a model-based management framework that facilitates this process. We propose a domain-specific modeling language that captures AMF domain concepts, relationships, and constraints, facilitating the management of AMF configurations. We define this language by extending UML through its profiling mechanism, capturing the concepts of AMF configurations and the description of the software for which the configuration will be generated. We introduce a new approach for the automatic generation of AMF configurations based on our UML profile using model transformation techniques. This approach consists of a set of transformations from the software description entities into AMF configurations while satisfying the requirements of the services to be provided as well as the constraints of the deployment infrastructure. We also propose a third-party AMF configuration validation approach consisting of syntactical and semantic validations. Syntactical validation checks the well-formedness of third-party configurations by validating them against AMF standard specification requirements captured in our UML profile. Semantic validation focuses on ensuring the runtime protection of services at configuration time (the SI-Protection problem). SI-Protection has combinatorial aspects and results in an NP-hard problem for most redundancy models, which we have tackled by devising a heuristic-based method, overcoming its complexity. We present proofs of concepts by using different available technologies: IBM Rational Software Architect (RSA) for implementing our UML profiles, Eclipse environment for developing a prototype tool for validating third-party configurations, and Atlas Transformation Language (ATL) for developing a prototype implementation of our model-based configuration generation approach

A UML-based domain specific modeling language for the availability management framework

The Service Availability Forum (SA Forum) is a consortium of several telecommunications and computing companies that defines standard solutions for high availability platforms. One of the most important SA Forum services is the Availability Management Framework (AMF) which is responsible for managing the availability of an application running under its control. To achieve this, AMF requires a complete configuration, which consists of several entities organized according to AMF rules and constraints. In this paper, we argue that AMF concepts form a domain for which a domain-specific modeling language can greatly facilitate the generation, analysis and the management of AMF configurations. We define such a language by extending UML through its profiling mechanism and we implement it. More important, we discuss the challenges and the lessons learned in the course of this project. \uc2\ua9 2010 IEEE

A Framework for Requirements Decomposition, SLA Management and Dynamic System Reconfiguration

To meet user requirements, systems can be built from Commercial-Off-The-Shelf (COTS) components, potentially from different vendors. However, the gap between the requirements referring to the overall system and the components to build the system from can be large. To close the gap, it is required to decompose the requirements to a level where they can be mapped to components. When the designed system is deployed and ready for operations, its services are sold and pro-vided to customers. One important goal for service providers is to optimize system resource utilization while ensuring the quality of service expressed in the Service Level Agreements (SLAs). For this purpose, the system can be reconfigured dynamically according to the cur-rent workload to satisfy the SLAs while using only necessary resources. To manage the re-configuration of the system at runtime, a set of previously defined patterns called elasticity rules can be used. In elasticity rules, the actions that need to be taken to reconfigure the sys-tem are specified. An elasticity rule is generally invoked by a trigger, which is generated in reaction to a monitoring event. In this thesis, we propose a model-driven management framework which aims at user re-quirements satisfaction, SLA compliance management and enabling dynamic reconfiguration by reusing the design information at runtime. An approach has been developed to derive automatically a valid configuration starting from low level requirements called service configurations. However, the service configurations are far from requirements a user would express. To generate a system configuration from user requirements and alleviate the work of designer, we generate service configurations by de-composing functional user requirements to the level where components can be selected and put together to satisfy the user requirements. We integrated our service configurations gen-erator with the previous configuration generator. In our framework, we reuse the information acquired from system configuration and dimen-sioning to generate elasticity rules offline. We propose a model driven approach to check the compliance of SLAs and generate triggers for invoking applicable elasticity rules when system reconfiguration is required. For handling multiple triggers generated at the same time, we propose a solution to automatically correlate the actions of invoked elasticity rules, when re-quired. The framework consists of a number of metamodels and a set of model transfor-mations. We use the Unified Modeling Language (UML) and its profiling mechanism to de-scribe all the artifacts in the proposed framework. We implement the profiles using Eclipse Modeling Framework (EMF) and Papyrus. To implement the processes, we use the Atlas Transformation Language (ATL). We also use the APIs of the Object Constraint Language (OCL) in the Eclipse environment to develop a tool for checking constraints and generating triggers

A Model-based Framework for System Configuration Management

A system can be viewed from different perspectives, each focusing on a specific aspect such as availability, performance, security. Configurations reflect the manageable resources of the system, their attributes and organization which are necessary for the management of the system for each aspect. Thus, for management purposes a system is generally described through various partial configurations (also known as configuration fragments). To form a consistent system con-figuration, these independently developed configuration fragments need to be integrated together. The integration of configuration fragments is a challenging task. This is mainly due to over-lapping entities (different logical representations of the same system resource) in the configuration fragments and/or complex relationships among the entities of the different configuration fragments. At runtime the system may be reconfigured to meet certain/new requirements or in response to performance degradations. These changes may lead to inconsistency as some changes may violate the constraints between entities. Maintaining the consistency and adjusting the system configuration at runtime is another challenging task. In our research, we propose to handle these two important issues in an integrated manner. We define a model-based framework for configuration management. We use the Unified Modeling Language (UML) and its profiling mechanism for representing the configuration fragments. Using model weaving and model trans-formation techniques, we propose a solution for the integration of configuration fragments targeting specific system properties. To handle runtime changes, we propose a configuration validation and adjustment solution to check and preserve the consistency of the system configuration. We introduce a partial validation technique in which the runtime reconfigurations are checked against a reduced set of consistency rules instead of the complete set of rules and the reconfigurations are applied only if they are safe, i.e. they preserve the configuration consistency. For handling the changes that violate the consistency rules, we propose an adjustment technique to automatically resolve (if possible) the inconsistencies. This is achieved by propagating the changes in the configuration according to the system constraints following the possible impacts of the configuration entities on each other. Some heuristics are used to reduce the complementary changes and to limit the propagation. We evaluate the complexity of our adjustment technique and conduct experiments to evaluate its efficiency. The Service Availability Forum middleware is used as an application domain in the examples throughout this thesis; however the proposed solutions are applicable in more general settings. We present proofs of concepts using different technologies. We use the Eclipse Modeling Framework (EMF) and Papyrus for implementing the UML profiles. The Atlas Model Weaver (AMW) and Atlas Transformation Language (ATL) are used to integrate the configuration fragments, and we also use the APIs of the Object Constraint Language (OCL) in the Eclipse environment and the Microsoft Z3 constraint solver to develop a prototype tool of our partial validation and adjustment agents

Automated Configuration Design and Analysis for Service High-Availability

The need for highly available services is ever increasing in various domains ranging from mission critical systems to transaction based ones such as online banking. The Service Availability Forum (SAForum) has defined a set of services and related Application Programming Interface (API) specifications to address the growing need of commercial-off-the-shelf high availability solutions. Among these services, the Availability Management Framework (AMF) is the service responsible for managing the high availability of the application services. To achieve this task, an AMF implementation requires a specific logical view of the organization of the application’s services and components, known as an AMF configuration. Any AMF configuration must be compliant to the concepts and constraints defined in the AMF specifications. The process of defining AMF configurations is error prone and requires extensive domain knowledge. Another major issue is being able to analyze the designed AMF configuration to quantify the anticipated service availability. This requires a different set of modeling and analysis skills that system integrators might not necessarily possess. In this dissertation we propose the automation of this process. The premise is to define a generation method within which we embed the domain knowledge and the domain constraints, and by that generating AMF configurations that are valid by construction. We also define an approach for the service availability analysis of AMF configurations. Our method is based on generating an analysis stochastic model that captures the middleware behavior and the application configuration. This model is thereafter solved to quantify the service availability