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
“Why didn’t testing catch this” must become “How did this make it to testing?” Traditional quality teams are the crutch and excuse keeping organizations from making the necessary investment in people, process, and technology to accelerate test automation. Just like societies that did not build waterways because the labor to keep carrying the water was so cheap, we have created disincentives to automate. In her session at @DevOpsSummit at 20th Cloud Expo, Anne Hungate, President of Daring System...
SYS-CON Events announced today that GrapeUp, the leading provider of rapid product development at the speed of business, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Grape Up is a software company, specialized in cloud native application development and professional services related to Cloud Foundry PaaS. With five expert teams that operate in various sectors of the market acr...
From 2013, NTT Communications has been providing cPaaS service, SkyWay. Its customer’s expectations for leveraging WebRTC technology are not only typical real-time communication use cases such as Web conference, remote education, but also IoT use cases such as remote camera monitoring, smart-glass, and robotic. Because of this, NTT Communications has numerous IoT business use-cases that its customers are developing on top of PaaS. WebRTC will lead IoT businesses to be more innovative and address...
SYS-CON Events announced today that CA Technologies has been named "Platinum Sponsor" of SYS-CON's 21st International Cloud Expo®, which will take place October 31-November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. CA Technologies helps customers succeed in a future where every business - from apparel to energy - is being rewritten by software. From planning to development to management to security, CA creates software that fuels transformation for companies in the applic...
For financial firms, the cloud is going to increasingly become a crucial part of dealing with customers over the next five years and beyond, particularly with the growing use and acceptance of virtual currencies. There are new data storage paradigms on the horizon that will deliver secure solutions for storing and moving sensitive financial data around the world without touching terrestrial networks. In his session at 20th Cloud Expo, Cliff Beek, President of Cloud Constellation Corporation, d...
Given the popularity of the containers, further investment in the telco/cable industry is needed to transition existing VM-based solutions to containerized cloud native deployments. The networking architecture of the solution isolates the network traffic into different network planes (e.g., management, control, and media). This naturally makes support for multiple interfaces in container orchestration engines an indispensable requirement.
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 21st Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devic...
In his opening keynote at 20th Cloud Expo, Michael Maximilien, Research Scientist, Architect, and Engineer at IBM, discussed the full potential of the cloud and social data requires artificial intelligence. By mixing Cloud Foundry and the rich set of Watson services, IBM's Bluemix is the best cloud operating system for enterprises today, providing rapid development and deployment of applications that can take advantage of the rich catalog of Watson services to help drive insights from the vast t...
Recently, IoT seems emerging as a solution vehicle for data analytics on real-world scenarios from setting a room temperature setting to predicting a component failure of an aircraft. Compared with developing an application or deploying a cloud service, is an IoT solution unique? If so, how? How does a typical IoT solution architecture consist? And what are the essential components and how are they relevant to each other? How does the security play out? What are the best practices in formulating...
In his session at @ThingsExpo, Arvind Radhakrishnen discussed how IoT offers new business models in banking and financial services organizations with the capability to revolutionize products, payments, channels, business processes and asset management built on strong architectural foundation. The following topics were covered: How IoT stands to impact various business parameters including customer experience, cost and risk management within BFS organizations.
SYS-CON Events announced today that Elastifile will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Elastifile Cloud File System (ECFS) is software-defined data infrastructure designed for seamless and efficient management of dynamic workloads across heterogeneous environments. Elastifile provides the architecture needed to optimize your hybrid cloud environment, by facilitating efficient...
As DevOps methodologies expand their reach across the enterprise, organizations face the daunting challenge of adapting related cloud strategies to ensure optimal alignment, from managing complexity to ensuring proper governance. How can culture, automation, legacy apps and even budget be reexamined to enable this ongoing shift within the modern software factory?
While some vendors scramble to create and sell you a fancy solution for monitoring your spanking new Amazon Lambdas, hear how you can do it on the cheap using just built-in Java APIs yourself. By exploiting a little-known fact that Lambdas aren’t exactly single-threaded, you can effectively identify hot spots in your serverless code. In his session at @DevOpsSummit at 21st Cloud Expo, Dave Martin, Product owner at CA Technologies, will give a live demonstration and code walkthrough, showing how ...
SYS-CON Events announced today that Golden Gate University will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Since 1901, non-profit Golden Gate University (GGU) has been helping adults achieve their professional goals by providing high quality, practice-based undergraduate and graduate educational programs in law, taxation, business and related professions. Many of its courses are taug...
@DevOpsSummit at Cloud Expo taking place Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center, Santa Clara, CA, is co-located with the 21st 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 ...