Microservices Expo Authors: Derek Weeks, Elizabeth White, Gopala Krishna Behara, Sridhar Chalasani, Tirumala Khandrika

Related Topics: Microservices Expo

Microservices Expo: Article

Differential QoS Support in Web Services Management

One service implementation - many levels of service

Web services are gaining acceptance as the prime technology used to interconnect disparate applications and ease interoperability between heterogeneous and autonomous systems both for internal and external integration. The variation of contexts in which shared Web services could be used and the resulting variation in functional and Quality of Service (QoS) requirements motivate extending Web services management platforms with more sophisticated control mechanisms to cater to differentiated service offerings.

However, most Web services platforms are based on a best-effort model, which treats all requests uniformly, without any type of service differentiation or prioritization. This article explores the typical generic requirements for differential QoS support in Web services management. We then evaluate various emerging management frameworks to assess the degree to which they meet the identified requirements. Finally we present the typical architecture for priority-based differentiated QoS for Web services.

Web Services Management
Web services management (WSM) provides the necessary infrastructure to help enterprises monitor, optimize, and control the Web services infrastructure by using a policy-oriented approach to ensure that QoS objectives are met. A WSM system provides visibility into the Web services runtime environment to enable:

  • Monitoring of availability, accessibility, and performance of Web services
  • Service level agreement (SLA)-compliance tracking
  • Error detection, resolution, and auditing
OASIS Web Services Distributed Management (WSDM) is a key standard for Web services management. It allows exposing management functionality in a reusable way through two specifications: one for Management Using Web Services (MUWS) and the other for Management of Web Services (MOWS). The MUWS specification provides a framework that defines how to represent and access the manageability interfaces of resources as Web services. MOWS builds on MUWS to define how to manage a Web service as a resource. It defines WSDL interfaces, which allows management events and metrics to be exposed, queried, and controlled by a broad range of management tools. However, WSDM does not provide any support for differential QoS.

Differential QoS Requirements in Web Services: One Service Implementation - Many Levels of Service
In the business world differentiated services are very common, just as gold card holders get preferential services compared to silver or bronze card holders. Leveraging the notion of differentiation to vary the level of service offerings in Web services environments is a challenging task. For example, a Stock Quote Web service could report prices with different levels of timeliness, ranging from real time to fifteen-minute delay to a 24-hour time lag. Service request metadata such as the grade of the service customer (gold, silver, etc.), or the security level (employee, customer, partner, etc.) could then be used to determine the service level to offer to the user at the time of request.

However, current Web services management platforms do not address differentiated services requirements comprehensively, and requests are often processed according to their order of arrival. Figure 1 summarizes the typical architectural requirements for differential QoS.

Generic service-level offerings - The first requirement to achieve differentiated QoS is the ability to encode QoS assurances in machine-readable format. An expressive language is required to specify the various service levels offered by the service provider. For example, services can be offered using an Olympic classification such as gold, silver and bronze.

Individualized service-level offerings - Besides the support for defining generic service levels, sometimes it is useful to be able to define custom service levels (SLAs) per service consumer.

Matching and negotiation of service levels - Particularly for custom SLAs, sometimes it is useful to be able to dynamically negotiate service levels depending on the requester's requirements, the service provider's capabilities, and the dynamic runtime conditions such as service load.

Admission control - Admission control regulates the "intake" and manages the acceptance of new requests while taking into account current service policies and system load. In case of overload, a request may be either rejected or have its QoS level downgraded (through negotiation), so that it can be accepted at a lower service class.

Request classification - Request classification is responsible for receiving incoming requests and assigning a service class to requests to enable prioritization according to a predefined classification schema. The request is then placed on the appropriate priority queue according to its assigned service class.

Requests policing - Requests policing is required to make sure that the number of requests per customer is within a predefined limit. Requests exceeding the maximum throughput limit are assigned a low priority class.

Differential QoS dispatcher - Dispatcher uses scheduling algorithms such as weighted round-robin scheme to dispatch requests for processing, while ensuring that the number of dispatched requests to each service does not exceed its capacity.

QoS measurement and monitoring - A QoS metrics engine is required to gather QoS metrics, monitor the workload, and readjust the class-of-service weights for request queues. This allows the Service provider to ensure that the promised performance is being delivered, and to take appropriate actions to rectify noncompliance with an SLA such as reprioritization and reallocation of resources.

Policy manager - For implementing differentiated services, there is typically a set of rules or policies that control the QoS variations. From an architectural point of view, this requires a separate policy management layer to allow separating out the policy aspects from service implementation.

Automated resource management - The most important and challenging requirement for differential QoS management is still QoS delivery through automated resource management, particularly arbitration in allocating resources to client requests (e.g., providing more resources to process higher priority requests) and mapping QoS requirements onto the configuration of underlying QoS provision technologies across all abstraction layers.

More Stories By Abhishek Malay Chatterjee

Abhishek Malay Chatterjee is working as part of the Web Services COE (Center of Excellence) for Infosys Technologies Ltd., a global IT consulting firm, and has substantial experience in publishing papers, presenting papers at conferences, and defining standards for SOA and Web services.

More Stories By Anshuk Pal Chaudhari

The authors are interning and/or working as part of the Web Services COE (Center of Excellence) for Infosys Technologies, a global IT consulting firm, and have substantial experience in publishing papers, presenting papers at conferences, and defining standards for SOA and Web services. The Web Services COE specializes in SOA, Web services, and other related technologies.

More Stories By Akash Saurav Das

The authors are interning and/or working as part of the Web Services COE (Center of Excellence) for Infosys Technologies, a global IT consulting firm, and have substantial experience in publishing papers, presenting papers at conferences, and defining standards for SOA and Web services. The Web Services COE specializes in SOA, Web services, and other related technologies.

More Stories By Terance Dias

The authors are interning and/or working as part of the Web Services COE (Center of Excellence) for Infosys Technologies, a global IT consulting firm, and have substantial experience in publishing papers, presenting papers at conferences, and defining standards for SOA and Web services. The Web Services COE specializes in SOA, Web services, and other related technologies.

More Stories By Abdelkarim Erradi

The authors are interning and/or working as part of the Web Services COE (Center of Excellence) for Infosys Technologies, a global IT consulting firm, and have substantial experience in publishing papers, presenting papers at conferences, and defining standards for SOA and Web services. The Web Services COE specializes in SOA, Web services, and other related technologies.

Comments (1) View Comments

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.

Most Recent Comments
Steve 09/13/05 02:16:11 AM EDT

Whats this?

@MicroservicesExpo Stories
Some people are directors, managers, and administrators. Others are disrupters. Eddie Webb (@edwardawebb) is an IT Disrupter for Software Development Platforms at Liberty Mutual and was a presenter at the 2016 All Day DevOps conference. His talk, Organically DevOps: Building Quality and Security into the Software Supply Chain at Liberty Mutual, looked at Liberty Mutual's transformation to Continuous Integration, Continuous Delivery, and DevOps. For a large, heavily regulated industry, this task...
DevOps promotes continuous improvement through a culture of collaboration. But in real terms, how do you: Integrate activities across diverse teams and services? Make objective decisions with system-wide visibility? Use feedback loops to enable learning and improvement? With technology insights and real-world examples, in his general session at @DevOpsSummit, at 21st Cloud Expo, Andi Mann, Chief Technology Advocate at Splunk, explored how leading organizations use data-driven DevOps to clos...
The goal of Microservices is to improve software delivery speed and increase system safety as scale increases. Microservices being modular these are faster to change and enables an evolutionary architecture where systems can change, as the business needs change. Microservices can scale elastically and by being service oriented can enable APIs natively. Microservices also reduce implementation and release cycle time and enables continuous delivery. This paper provides a logical overview of the Mi...
The notion of improving operational efficiency is conspicuously absent from the healthcare debate - neither Obamacare nor the newly proposed GOP plan discusses the impact that a step-function improvement in efficiency could have on access to healthcare (through more capacity), quality of healthcare services (through reduced wait times for patients) or cost (through better utilization of scarce, expensive assets).
Our work, both with clients and with tools, has lead us to wonder how it is that organizations are handling compliance issues in the cloud. The big cloud vendors offer compliance for their infrastructure, but the shared responsibility model requires that you take certain steps to meet compliance requirements. Which lead us to start poking around a little more. We wanted to get a picture of what was available, and how it was being used. There is a lot of fluidity in this space, as in all things c...
Gone are the days when application development was the daunting task of the highly skilled developers backed with strong IT skills, low code application development has democratized app development and empowered a new generation of citizen developers. There was a time when app development was in the domain of people with complex coding and technical skills. We called these people by various names like programmers, coders, techies, and they usually worked in a world oblivious of the everyday pri...
The “Digital Era” is forcing us to engage with new methods to build, operate and maintain applications. This transformation also implies an evolution to more and more intelligent applications to better engage with the customers, while creating significant market differentiators. In both cases, the cloud has become a key enabler to embrace this digital revolution. So, moving to the cloud is no longer the question; the new questions are HOW and WHEN. To make this equation even more complex, most ...
Some journey to cloud on a mission, others, a deadline. Change management is useful when migrating to public, private or hybrid cloud environments in either case. For most, stakeholder engagement peaks during the planning and post migration phases of a project. Legacy engagements are fairly direct: projects follow a linear progression of activities (the “waterfall” approach) – change managers and application coders work from the same functional and technical requirements. Enablement and develo...
Admiral Calcote - also known as Lee Calcote (@lcalcote) or the Ginger Geek to his friends - gave a presentation entitled Characterizing and Contrasting Container Orchestrators at the 2016 All Day DevOps conference. Okay, he isn't really an admiral - nor does anyone call him that - but he used the title admiral to describe what container orchestrators do, relating it to an admiral directing a fleet of container ships. You could also say that they are like the conductor of an orchestra, directing...
The past few years have brought a sea change in the way applications are architected, developed, and consumed—increasing both the complexity of testing and the business impact of software failures. How can software testing professionals keep pace with modern application delivery, given the trends that impact both architectures (cloud, microservices, and APIs) and processes (DevOps, agile, and continuous delivery)? This is where continuous testing comes in. D
Modern software design has fundamentally changed how we manage applications, causing many to turn to containers as the new virtual machine for resource management. As container adoption grows beyond stateless applications to stateful workloads, the need for persistent storage is foundational - something customers routinely cite as a top pain point. In his session at @DevOpsSummit at 21st Cloud Expo, Bill Borsari, Head of Systems Engineering at Datera, explored how organizations can reap the bene...
The dynamic nature of the cloud means that change is a constant when it comes to modern cloud-based infrastructure. Delivering modern applications to end users, therefore, is a constantly shifting challenge. Delivery automation helps IT Ops teams ensure that apps are providing an optimal end user experience over hybrid-cloud and multi-cloud environments, no matter what the current state of the infrastructure is. To employ a delivery automation strategy that reflects your business rules, making r...
Gaining visibility in today’s sprawling cloud infrastructure is complex and laborious, involving drilling down into tools offered by various cloud services providers. Enterprise IT organizations need smarter and effective tools at their disposal in order to address this pertinent problem. Gaining a 360 - degree view of the cloud costs requires collection and analysis of the cost data across all cloud infrastructures used inside an enterprise.
SYS-CON Events announced today that Synametrics Technologies will exhibit at SYS-CON's 22nd International Cloud Expo®, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Synametrics Technologies is a privately held company based in Plainsboro, New Jersey that has been providing solutions for the developer community since 1997. Based on the success of its initial product offerings such as WinSQL, Xeams, SynaMan and Syncrify, Synametrics continues to create and hone in...
Kubernetes is an open source system for automating deployment, scaling, and management of containerized applications. Kubernetes was originally built by Google, leveraging years of experience with managing container workloads, and is now a Cloud Native Compute Foundation (CNCF) project. Kubernetes has been widely adopted by the community, supported on all major public and private cloud providers, and is gaining rapid adoption in enterprises. However, Kubernetes may seem intimidating and complex ...
You know you need the cloud, but you’re hesitant to simply dump everything at Amazon since you know that not all workloads are suitable for cloud. You know that you want the kind of ease of use and scalability that you get with public cloud, but your applications are architected in a way that makes the public cloud a non-starter. You’re looking at private cloud solutions based on hyperconverged infrastructure, but you’re concerned with the limits inherent in those technologies.
For DevOps teams, the concepts behind service-oriented architecture (SOA) are nothing new. A style of software design initially made popular in the 1990s, SOA was an alternative to a monolithic application; essentially a collection of coarse-grained components that communicated with each other. Communication would involve either simple data passing or two or more services coordinating some activity. SOA served as a valid approach to solving many architectural problems faced by businesses, as app...
Many IT organizations have come to learn that leveraging cloud infrastructure is not just unavoidable, it’s one of the most effective paths for IT organizations to become more responsive to business needs. Yet with the cloud comes new challenges, including minimizing downtime, decreasing the cost of operations, and preventing employee burnout to name a few. As companies migrate their processes and procedures to their new reality of a cloud-based infrastructure, an incident management solution...
Cloud Governance means many things to many people. Heck, just the word cloud means different things depending on who you are talking to. While definitions can vary, controlling access to cloud resources is invariably a central piece of any governance program. Enterprise cloud computing has transformed IT. Cloud computing decreases time-to-market, improves agility by allowing businesses to adapt quickly to changing market demands, and, ultimately, drives down costs.
Recent survey done across top 500 fortune companies shows almost 70% of the CIO have either heard about IAC from their infrastructure head or they are on their way to implement IAC. Yet if you look under the hood while some level of automation has been done, most of the infrastructure is still managed in much tradition/legacy way. So, what is Infrastructure as Code? how do you determine if your IT infrastructure is truly automated?