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
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
Whether your IoT service is connecting cars, homes, appliances, wearable, cameras or other devices, one question hangs in the balance – how do you actually make money from this service? The ability to turn your IoT service into profit requires the ability to create a monetization strategy that is flexible, scalable and working for you in real-time. It must be a transparent, smoothly implemented strategy that all stakeholders – from customers to the board – will be able to understand and comprehe...
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
"We are a leader in the market space called network visibility solutions - it enables monitoring tools and Big Data analysis to access the data and be able to see the performance," explained Shay Morag, VP of Sales and Marketing at Niagara Networks, in this SYS-CON.tv interview at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
"We analyze the video streaming experience. We are gathering the user behavior in real time from the user devices and we analyze how users experience the video streaming," explained Eric Kim, Founder and CEO at Streamlyzer, in this SYS-CON.tv interview at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
In his session at Cloud Expo, Robert Cohen, an economist and senior fellow at the Economic Strategy Institute, provideed economic scenarios that describe how the rapid adoption of software-defined everything including cloud services, SDDC and open networking will change GDP, industry growth, productivity and jobs. This session also included a drill down for several industries such as finance, social media, cloud service providers and pharmaceuticals.
Extracting business value from Internet of Things (IoT) data doesn’t happen overnight. There are several requirements that must be satisfied, including IoT device enablement, data analysis, real-time detection of complex events and automated orchestration of actions. Unfortunately, too many companies fall short in achieving their business goals by implementing incomplete solutions or not focusing on tangible use cases. In his general session at @ThingsExpo, Dave McCarthy, Director of Products...
@DevOpsSummit at Cloud taking place June 6-8, 2017, at Javits Center, New York City, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long developm...
SYS-CON Events has announced today that Roger Strukhoff has been named conference chair of Cloud Expo and @ThingsExpo 2017 New York. The 20th Cloud Expo and 7th @ThingsExpo will take place on June 6-8, 2017, at the Javits Center in New York City, NY. "The Internet of Things brings trillions of dollars of opportunity to developers and enterprise IT, no matter how you measure it," stated Roger Strukhoff. "More importantly, it leverages the power of devices and the Internet to enable us all to im...
Businesses and business units of all sizes can benefit from cloud computing, but many don't want the cost, performance and security concerns of public cloud nor the complexity of building their own private clouds. Today, some cloud vendors are using artificial intelligence (AI) to simplify cloud deployment and management. In his session at 20th Cloud Expo, Ajay Gulati, Co-founder and CEO of ZeroStack, will discuss how AI can simplify cloud operations. He will cover the following topics: why clou...
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
Kubernetes is a new and revolutionary open-sourced system for managing containers across multiple hosts in a cluster. Ansible is a simple IT automation tool for just about any requirement for reproducible environments. In his session at @DevOpsSummit at 18th Cloud Expo, Patrick Galbraith, a principal engineer at HPE, discussed how to build a fully functional Kubernetes cluster on a number of virtual machines or bare-metal hosts. Also included will be a brief demonstration of running a Galera MyS...
Internet-of-Things discussions can end up either going down the consumer gadget rabbit hole or focused on the sort of data logging that industrial manufacturers have been doing forever. However, in fact, companies today are already using IoT data both to optimize their operational technology and to improve the experience of customer interactions in novel ways. In his session at @ThingsExpo, Gordon Haff, Red Hat Technology Evangelist, will share examples from a wide range of industries – includin...
"We build IoT infrastructure products - when you have to integrate different devices, different systems and cloud you have to build an application to do that but we eliminate the need to build an application. Our products can integrate any device, any system, any cloud regardless of protocol," explained Peter Jung, Chief Product Officer at Pulzze Systems, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Keeping pace with advancements in software delivery processes and tooling is taxing even for the most proficient organizations. Point tools, platforms, open source and the increasing adoption of private and public cloud services requires strong engineering rigor – all in the face of developer demands to use the tools of choice. As Agile has settled in as a mainstream practice, now DevOps has emerged as the next wave to improve software delivery speed and output. To make DevOps work, organization...