Welcome!

Machine Learning Authors: Elizabeth White, Pat Romanski, Yeshim Deniz, Liz McMillan, Shelly Palmer

Related Topics: @CloudExpo, Microservices Expo, Microsoft Cloud, Containers Expo Blog, Machine Learning , Apache

@CloudExpo: Blog Feed Post

Load Balancing 101: Scale versus Fail

Elasticity is a design pattern for scalability, not necessarily failability.

One of the phrases you hear associated with cloud computing is "architecting for failure." Rather than build in a lot of hardware-level redundancy – power, disk, network, etc… – the idea is that you expect it to fail and can simply replace the application (which is what you care about anyway, right?) with a clone running on the same cheap hardware somewhere else in the data center.

Awesome idea, right?

But when it comes down to it, cloud computing environments are architected for scale, not fail.

lb-scale-vs-fail

SCALE versus FAIL

Most enterprise-class data centers have been architected with failure in mind; we call these high-availability (HA) architectures. The goal is to ensure that if any element in the data path fails that another can almost immediately take its place. Within a hardware platform, this implies dual power supplies, a high RAID level, and lights-out management. At the network and higher level, this requires redundant network elements – from load balancers to switches to routers to firewalls to servers, all elements must be duplicated to ensure a (near) immediate failover in the event of a failure. This generally requires configurations and support for floating (shared) IP addresses across redundant elements, allowing for immediate redirection upon detection of a failure upstream.

At the application/server tier, the shared address concept is still applied but it is done so at the load balancing layer, where VIP (virtual IP addresses) act as a virtual instance of the application. A primary node (server) is designated that is active with a secondary being designated as the "backup" instance which remains idle in "standby" mode*.

If the primary instance fails – whether due to hardware or software or network failure – the secondary immediately becomes active, and continuity of service is assured by virtue of the fact that existing sessions are managed by the load balancing service, not the server. In the event a network element fails, continuity (high-availability) is achieved due to the mirroring (replication) of those same sessions between the active (primary) and standby (secondary) elements. inoneminute1

Is it perfect? No, but it does provide sub-second response to failure, which means very high levels of availability (or as I like to call it, failability).

That's architected for "FAIL".

Now, most cloud computing environments are architected not with failure in mind but with scale in mind – that is, they are designed to enable elasticity (scale out, scale in) that is, in part, based on the ability to rapidly provision the resources required.

A load balancing instance is required and it works in much the same way as a high-availability architecture (minus the redundancy). The load balancing service acts as the virtual application, with at least one instance behind it. As demand increases, new instances are provisioned and added to the service to ensure that performance and availability are not adversely impacted. When this process is also capable of scaling back in by automatically eliminating instances when demand contracts it's called "elasticity".

If the only instance available fails, this architecture is not going to provide high availability of the application because it takes time to launch an instance to replace it. Even if there are ten active instances and one fails, performance and/or availability for some clients may be impacted because, as noted already, it takes time to launch an instance to replace it.

Similarly, if an upstream element fails, such as the load balancing service, availability may be adversely impacted – because it takes time to replace it.

But when considering how well the system responds to changes in demand for resources, it works well. That's scalability.

That's architected for "SCALE".

SCALE and FAIL are NOT INTERCHANGEABLE

These two are not interchangeable, they cannot be conflated with the expectation that either architecture is able to meet both goals equally well. They are designed to resolve two different problems.

The two can be combined to achieve a scalable, high-availability architecture where redundancy is used to assure availability while elasticity is leveraged to realize scale while reducing the time to provision and investment costs by implementing a virtual, flexible resource model.

It's important to understand the difference in these architectures especially when looking to public cloud as an option because they are primarily designed to enable scalability, not failability. If you absolutely need failability, you'll need to do some legwork of your own (scripts or manual intervention – perhaps both) to ensure a more seamless failover in the event of failure or specifically seek out cloud providers that recognize the inherent differences between the two architectures and support either the one you need, or both.

Relying on an elastic architecture to provide high-availability – or vice-versa – is likely to end poorly.


Downtime cost source: IT Downtime Costs $26.5 Billion In Lost Revenue

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.

@CloudExpo Stories
New competitors, disruptive technologies, and growing expectations are pushing every business to both adopt and deliver new digital services. This ‘Digital Transformation’ demands rapid delivery and continuous iteration of new competitive services via multiple channels, which in turn demands new service delivery techniques – including DevOps. In this power panel at @DevOpsSummit 20th Cloud Expo, moderated by DevOps Conference Co-Chair Andi Mann, panelists will examine how DevOps helps to meet th...
SYS-CON Events announced today that Progress, a global leader in application development, has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Enterprises today are rapidly adopting the cloud, while continuing to retain business-critical/sensitive data inside the firewall. This is creating two separate data silos – one inside the firewall and the other outside the firewall. Cloud ISVs oft...
Multiple data types are pouring into IoT deployments. Data is coming in small packages as well as enormous files and data streams of many sizes. Widespread use of mobile devices adds to the total. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists will look at the tools and environments that are being put to use in IoT deployments, as well as the team skills a modern enterprise IT shop needs to keep things running, get a handle on all this data, and deli...
One of the biggest challenges with adopting a DevOps mentality is: new applications are easily adapted to cloud-native, microservice-based, or containerized architectures - they can be built for them - but old applications need complex refactoring. On the other hand, these new technologies can require relearning or adapting new, oftentimes more complex, methodologies and tools to be ready for production. In his general session at @DevOpsSummit at 20th Cloud Expo, Chris Brown, Solutions Marketi...
SYS-CON Events announced today that Interoute has been named “Bronze Sponsor” of SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Interoute is the owner operator of Europe's largest network and a global cloud services platform, which encompasses over 70,000 km of lit fiber, 15 data centers, 17 virtual data centers and 33 colocation centers, with connections to 195 additional partner data centers. Our full-service Unifie...
The 21st International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Digital Transformation, Machine Learning and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding busin...
Everywhere we turn in our industry we can find strong opinions about the direction, type and nature of cloud’s impact on computing and business. Another word that is used in every context in our industry is “hybrid.” In his session at 20th Cloud Expo, Alvaro Gonzalez, Director of Technical, Partner and Field Marketing at Peak 10, will use a combination of a few conceptual props and some research recently commissioned by Peak 10 to offer a real-world consideration of how the various categories of...
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm.
SYS-CON Events announced today that Carbonite will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Carbonite protects your entire IT footprint with the right level of protection for each workload, ensuring lower costs and dependable solutions with DoubleTake and Evault.
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in 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. @ThingsExpo Silicon Valley Call for Papers is now open.
SYS-CON Events announced today that Twistlock, the leading provider of cloud container security solutions, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Twistlock is the industry's first enterprise security suite for container security. Twistlock's technology addresses risks on the host and within the application of the container, enabling enterprises to consistently enforce security policies, monitor...
The hot topics in the industry today seem to center around Digital Transformation and Mobile Apps. While a digital transformation strategy is crucial to keep up with the chaos in your industry, customer demands, and other disruptions, the need to create mobile apps to remain relevant in your market and to your customers is equally a no-brainer. Regardless of the approach, the next question always seems to pop up: What architecture should I chose? Native? Hybrid? Managed? Hosted?
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
SYS-CON Events announced today that EARP Integration will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. EARP Integration is a passionate software house. Since its inception in 2009 the company successfully delivers smart solutions for cities and factories that start their digital transformation. EARP provides bespoke solutions like, for example, advanced enterprise portals, business intelligence systems an...
SYS-CON Events announced today that Ocean9will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. Ocean9 provides cloud services for Backup, Disaster Recovery (DRaaS) and instant Innovation, and redefines enterprise infrastructure with its cloud native subscription offerings for mission critical SAP workloads.
SYS-CON Events announced today that T-Mobile will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 6-8, 2017, at the Javits Center in New York City, NY. As America's Un-carrier, T-Mobile US, Inc., is redefining the way consumers and businesses buy wireless services through leading product and service innovation. The Company's advanced nationwide 4G LTE network delivers outstanding wireless experiences to 67.4 million customers who are unwilling to compromise on ...
SYS-CON Events announced today that SoftLayer, an IBM Company, has been named “Gold Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2016, at the Javits Center in New York, New York. SoftLayer, an IBM Company, provides cloud infrastructure as a service from a growing number of data centers and network points of presence around the world. SoftLayer’s customers range from Web startups to global enterprises.
SYS-CON Events announced today that CollabNet, a global leader in enterprise software development, release automation and DevOps solutions, will be a Bronze Sponsor of SYS-CON's 20th International Cloud Expo®, taking place from June 6-8, 2017, at the Javits Center in New York City, NY. CollabNet offers a broad range of solutions with the mission of helping modern organizations deliver quality software at speed. The company’s latest innovation, the DevOps Lifecycle Manager (DLM), supports Value S...
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?