Welcome!

Related Topics: @DevOpsSummit, Java IoT, Linux Containers, @CloudExpo, @BigDataExpo, SDN Journal

@DevOpsSummit: Blog Post

Why Scaling Down Is Harder Than Scaling Up

Elasticity should be non-disruptive

Elasticity is hailed as one of the biggest benefits of cloud and software-defined architectures. It's more efficient than traditional scalability models that only went one direction: up. It's based on the premise that wasting money and resources all the time just to ensure capacity on a seasonal or periodic basis is not only unappealing, but unnecessary in the age of software-defined everything.

The problem is that scaling down is much, much harder than scaling up. Oh, not from the perspective of automation and orchestration. That is, as the kids say these days, easy peasy lemon squeezy. APIs have made the ability to add and remove resources simplicity itself. There isn't a load balancing service available today without this capability - at least not one that's worth having.

But if you peek behind the kimono, you're going to quickly find out that perhaps it isn't as easy peasy as it first appears. Scaling down requires a bit more finesse than scaling up, at least if you care about the end user experience.

Consider for a moment the process of scaling up (or out, as is more often the case). A certain threshold is reached that indicates a need for more capacity. More often than not this metric is based on connections, with each application instance able to handle an approximate number of connections. When that is reached, a new application instance (node) is launched, it's added to the load balanced pool, and voila! More capacity, more connections, more consumers.

awkward elasticity

At some point that same threshold is breached on the way back down. As capacity demand wanes, the total connection count (as measured by all connections across all instances) decreases. When that count crossed a pre-determined threshold, one instance is shut down, it's removed from the pool, and voila!

You've just disconnected a whole bunch of consumers - many of whom might have been in the middle of a transaction (you know, trying to give you money).

Needless to say, they aren't happy.

That's because many of the systems implementing elastic scale these days haven't been load balancing applications for nearly twenty years and didn't recognize the importance of graceful degradation, or quiescence.

Graceful degradation was used in the olden days (and still is today, to be fair) when initiating a maintenance cycle. The requirement was that a server (today an instance) needed to be shut down for maintenance but it could not disrupt current user sessions. The load balancer would be "told" to begin quiescing (or bleeding off) connections in preparation for downtime. The service would immediately stop sending new connections to that server (instance) while allowing existing connections to complete. In this way, consumers could complete their tasks and when no connections were left, the server would be shut down and maintenance could begin.

This is not a simple thing to achieve. The load balancing service must be intelligent enough to stop sending new connections to an instance but not interrupt existing connections. It must be able to manage both active and semi-active instances for the same application, which requires stateful management across all application instances.

In today's models, this means that elasticity must embrace a more graceful, elegant means of scaling down than just suddenly killing an instance and all its associated connections.

With more and more apps - both those aimed at employees and those designed for consumers - residing in cloud environments and managed service environments, it is critical to evaluate how such providers support elasticity. Methods that disrupt productivity or interrupt consumer transactions are hardly worth the few pennies saved by immediately shutting down an instance when a threshold is crossed.

It behooves emerging software-defined models and devops that plan on managing scale automatically to recognize that elasticity isn't just about responding to thresholds; it's about responding seamlessly - in both directions.

Read the original blog entry...

More Stories By Lori MacVittie

Lori MacVittie is responsible for education and evangelism of application services available across F5’s entire product suite. Her role includes authorship of technical materials and participation in a number of community-based forums and industry standards organizations, among other efforts. MacVittie has extensive programming experience as an application architect, as well as network and systems development and administration expertise. Prior to joining F5, MacVittie was an award-winning Senior Technology Editor at Network Computing Magazine, where she conducted product research and evaluation focused on integration with application and network architectures, and authored articles on a variety of topics aimed at IT professionals. Her most recent area of focus included SOA-related products and architectures. She holds a B.S. in Information and Computing Science from the University of Wisconsin at Green Bay, and an M.S. in Computer Science from Nova Southeastern University.

Latest Stories
SYS-CON Events announced today the How to Create Angular 2 Clients for the Cloud Workshop, being held June 7, 2016, in conjunction with 18th Cloud Expo | @ThingsExpo, at the Javits Center in New York, NY. Angular 2 is a complete re-write of the popular framework AngularJS. Programming in Angular 2 is greatly simplified. Now it’s a component-based well-performing framework. The immersive one-day workshop led by Yakov Fain, a Java Champion and a co-founder of the IT consultancy Farata Systems and...
SYS-CON Events announced today that Super Micro Computer, Inc., a global leader in Embedded and IoT solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Supermicro (NASDAQ: SMCI), the leading innovator in high-performance, high-efficiency server technology, is a premier provider of advanced server Building Block Solutions® for Data Center, Cloud Computing, Enterprise IT, Hadoop/Big Data, HPC and ...
In his session at 18th Cloud Expo, Andrew Cole, Director of Solutions Engineering at Peak 10, will discuss how the newest technology advances are reducing the cost and complexity of traditional business continuity and disaster recovery solutions. Attendees will: Learn why having a full disaster recovery strategy is more important now than ever before Explore the key drivers of a successful disaster recovery solution Achieve measurable operational and business value from a disaster recovery ...
How will your company move to the cloud while ensuring a solid security posture? Organizations from small to large are increasingly adopting cloud solutions to deliver essential business services at a much lower cost. According to cyber security experts, the frequency and severity of cyber-attacks are on the rise, causing alarm to businesses and customers across a variety of industries. To defend against exploits like these, a company must adopt a comprehensive security defense strategy that is ...
SYS-CON Events announced today that Hanu Software will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Leveraging best-in-class people, processes, and technologies, Hanu provides high-quality, high-value software development and business process outsourcing services to independent software vendors (ISVs) and enterprises.
What a difference a year makes. Organizations aren’t just talking about IoT possibilities, it is now baked into their core business strategy. With IoT, billions of devices generating data from different companies on different networks around the globe need to interact. From efficiency to better customer insights to completely new business models, IoT will turn traditional business models upside down. In the new customer-centric age, the key to success is delivering critical services and apps wit...
Join us at Cloud Expo | @ThingsExpo 2016 – June 7-9 at the Javits Center in New York City and November 1-3 at the Santa Clara Convention Center in Santa Clara, CA – and deliver your unique message in a way that is striking and unforgettable by taking advantage of SYS-CON's unmatched high-impact, result-driven event / media packages.
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, will provide an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life ...
The initial debate is over: Any enterprise with a serious commitment to IT is migrating to the cloud. But things are not so simple. There is a complex mix of on-premises, colocated, and public-cloud deployments. In this power panel at 18th Cloud Expo, moderated by Conference Chair Roger Strukhoff, panelists will look at the present state of cloud from the C-level view, and how great companies and rock star executives can use cloud computing to meet their most ambitious and disruptive business ...
SYS-CON Events announced today that MobiDev will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. MobiDev is a software company that develops and delivers turn-key mobile apps, websites, web services, and complex software systems for startups and enterprises. Since 2009 it has grown from a small group of passionate engineers and business managers to a full-scale mobile software company with over 200 develope...
SYS-CON Events announced today that BMC Software has been named "Siver Sponsor" of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. BMC is a global leader in innovative software solutions that help businesses transform into digital enterprises for the ultimate competitive advantage. BMC Digital Enterprise Management is a set of innovative IT solutions designed to make digital business fast, seamless, and optimized from mainframe to mo...
As cloud and storage projections continue to rise, the number of organizations moving to the cloud is escalating and it is clear cloud storage is here to stay. However, is it secure? Data is the lifeblood for government entities, countries, cloud service providers and enterprises alike and losing or exposing that data can have disastrous results. There are new concepts for data storage on the horizon that will deliver secure solutions for storing and moving sensitive data around the world. ...
SoftLayer operates a global cloud infrastructure platform built for Internet scale. With a global footprint of data centers and network points of presence, SoftLayer provides infrastructure as a service to leading-edge customers ranging from Web startups to global enterprises. SoftLayer's modular architecture, full-featured API, and sophisticated automation provide unparalleled performance and control. Its flexible unified platform seamlessly spans physical and virtual devices linked via a world...
SYS-CON Events announced today that ContentMX, the marketing technology and services company with a singular mission to increase engagement and drive more conversations for enterprise, channel and SMB technology marketers, has been named “Sponsor & Exhibitor Lounge Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York City, New York. “CloudExpo is a great opportunity to start a conversation with new prospects, but what happens after the...
Companies can harness IoT and predictive analytics to sustain business continuity; predict and manage site performance during emergencies; minimize expensive reactive maintenance; and forecast equipment and maintenance budgets and expenditures. Providing cost-effective, uninterrupted service is challenging, particularly for organizations with geographically dispersed operations.