|By Lori MacVittie||
|April 9, 2010 01:00 PM EDT||
Stateless applications may be the long term answer to scalability of applications in the cloud, but until then, we need a solution like sticky sessions (persistence)
Amazon recently introduced “stickiness” to its ELB (Elastic Load Balancing) offering. I’ve written a bit about “stickiness”, a.k.a. what we’ve called persistence for oh, nearly ten years now, before so I won’t reiterate again but to say, “it’s about time.” A description of why sticky sessions is necessary was offered in the AWS blog announcing the new feature:
Up until now each Load balancer had the freedom to forward each incoming HTTP or TCP request to any of the EC2 instances under its purview. This resulted in a reasonably even load on each instance, but it also meant that each instance would have to retrieve, manipulate, and store session data for each request without any possible benefit from locality of reference.
What the author is really trying to say is that without “sticky sessions” ELB breaks applications because it does not honor state. Remember that most web applications today rely upon state (session) to store quite a bit of application and user specific data that’s necessary for the application to behave properly. When a load balancer distributes requests across instances without consideration for where that state (session) is stored, the application behavior can become erratic and unpredictable. Hence the need for “stickiness”.
In addition to web applications relying heavily on state, so too do the APIs used to integrate them with each other and with other Web 2.0 applications like Twitter and Facebook and <insert favorite app here>. So called “REST” APIs today aren’t really REST. We know that. They’re RESTful but they aren’t truly REST according to the definition laid down primarily because they aren’t stateless. It turns out state and application development is not just a concern of application architects and developers these days, but of infrastructure vendors, pundits, analysts, and anyone interested in the evolution of cloud computing and a truly distributed, portable model of application deployment and delivery.
State is, to sum up the viewpoint, a sticking point.
As I see it there are two major types of workloads that a organisation is going to want to run on an external Cloud. The new breed which are built for the new Cloud model. These will scale out, be light weight, stateless and fit perfectly with a consumption based model. Run a few small VM's, with low RAM and CPU consumption, as demand increases the application dynamically scales itself out to meet demand, whether that be user generated or application generated, such as a month end processing run. -- Rodney Haywood: The Granularity of On-Demand Cloud - Today vs Tomorrow
Stateless. It was something we heard sprinkled throughout conversations at CloudConnect, as well. The best “workload” to run in a cloud is a “stateless” web application. Developers have to change the way they develop applications – they must go stateless. Portability requires (read: would be easier to implement) if applications were stateless.
That’s easy to say but a lot more difficult to implement.
The first greatest and most useful hack involving the web was enabling state for HTTP. Prior to the advent of sessions and state, the web was pretty much like interacting with a technicolor mainframe application. Folks even referred to “pages” as “screens”, in reference to the way in which one statically walked through big iron applications in a very linear and uncompromising fashion. Made a mistake? Not acceptable. “Back” and “previous” were foreign concepts. You had to effectively start over and change the existing transaction, which had likely already been committed to the database (assuming there was one). Sessions provided the ability to allow for mistakes and to allow better navigation options within an application. That’s because the transaction wasn’t committed to the database until the user was ready. Data entered in “step 1” could be modified after “step 4” with little effort on the part of the developer. AJAX has made this even easier, as it makes editing data after the fact (or during the process) able to directly transact with the database on a very granular, i.e. field or column, level basis.
Storing all state on the client would have an impact on just about the entire infrastructure stack and would also likely negatively impact many mobile applications, an increasingly popular client model that should not be ignored in decisions regarding the amount of data being exchanged between client and server.
Thus it is that “stateless” applications are unlikely to become the norm for some time (if ever). State is a necessary “evil”, though it’s “evilness” is certainly, like beauty, in the eye of the developer. Assuming that stateful applications remain the norm in the cloud means that load balancing services in those clouds must necessarily support the notion of persistence (stickiness) to ensure applications don’t break upon deployment. This also results in making it easier for organizations to migrate non-native “cloud” applications to EC2, because there’s no requirement that the application be rewritten in order to run properly (taking into consideration state/session) in a scalable environment.
Thus, Amazon introducing “sticky sessions” to ELB is a Very Good Thing.
The Internet of Things (IoT) is growing rapidly by extending current technologies, products and networks. By 2020, Cisco estimates there will be 50 billion connected devices. Gartner has forecast revenues of over $300 billion, just to IoT suppliers. Now is the time to figure out how you’ll make money – not just create innovative products. With hundreds of new products and companies jumping into the IoT fray every month, there’s no shortage of innovation. Despite this, McKinsey/VisionMobile data...
Nov. 30, 2015 03:00 PM EST Reads: 491
One of the most important tenets of digital transformation is that it’s customer-driven. In fact, the only reason technology is involved at all is because today’s customers demand technology-based interactions with the companies they do business with. It’s no surprise, therefore, that we at Intellyx agree with Patrick Maes, CTO, ANZ Bank, when he said, “the fundamental element in digital transformation is extreme customer centricity.” So true – but note the insightful twist that Maes adde...
Nov. 30, 2015 02:00 PM EST Reads: 460
Just over a week ago I received a long and loud sustained applause for a presentation I delivered at this year’s Cloud Expo in Santa Clara. I was extremely pleased with the turnout and had some very good conversations with many of the attendees. Over the next few days I had many more meaningful conversations and was not only happy with the results but also learned a few new things. Here is everything I learned in those three days distilled into three short points.
Nov. 30, 2015 02:00 PM EST Reads: 366
DevOps is about increasing efficiency, but nothing is more inefficient than building the same application twice. However, this is a routine occurrence with enterprise applications that need both a rich desktop web interface and strong mobile support. With recent technological advances from Isomorphic Software and others, rich desktop and tuned mobile experiences can now be created with a single codebase – without compromising functionality, performance or usability. In his session at DevOps Su...
Nov. 30, 2015 01:45 PM EST Reads: 429
As organizations realize the scope of the Internet of Things, gaining key insights from Big Data, through the use of advanced analytics, becomes crucial. However, IoT also creates the need for petabyte scale storage of data from millions of devices. A new type of Storage is required which seamlessly integrates robust data analytics with massive scale. These storage systems will act as “smart systems” provide in-place analytics that speed discovery and enable businesses to quickly derive meaningf...
Nov. 30, 2015 01:45 PM EST Reads: 434
This morning on #c9d9 we spoke with two industry veterans and published authors - James DeLuccia and Jonathan McAllister - on how to bake-in security and compliance into your DevOps processes, and how DevOps and automation can essentially help you pass your next audit.
Nov. 30, 2015 01:30 PM EST
Nov. 30, 2015 01:30 PM EST Reads: 249
The annual holiday shopping season, which started on Thanksgiving weekend and runs through the end of December, is undoubtedly the most crucial time of the year for many eCommerce websites, with sales from this period having a dramatic effect on the year-end bottom line. Web performance – or, the overall speed and availability of a website or mobile site – is an issue year-round, but it takes on increased importance during the holidays. Ironically, it is at this time of year that networks and i...
Nov. 30, 2015 12:45 PM EST
Countless business models have spawned from the IaaS industry – resell Web hosting, blogs, public cloud, and on and on. With the overwhelming amount of tools available to us, it's sometimes easy to overlook that many of them are just new skins of resources we've had for a long time. In his general session at 17th Cloud Expo, Harold Hannon, Sr. Software Architect at SoftLayer, an IBM Company, broke down what we have to work with, discussed the benefits and pitfalls and how we can best use them ...
Nov. 30, 2015 11:45 AM EST
Discussions of cloud computing have evolved in recent years from a focus on specific types of cloud, to a world of hybrid cloud, and to a world dominated by the APIs that make today's multi-cloud environments and hybrid clouds possible. In this Power Panel at 17th Cloud Expo, moderated by Conference Chair Roger Strukhoff, panelists addressed the importance of customers being able to use the specific technologies they need, through environments and ecosystems that expose their APIs to make true ...
Nov. 30, 2015 08:00 AM EST Reads: 565
Microservices are a very exciting architectural approach that many organizations are looking to as a way to accelerate innovation. Microservices promise to allow teams to move away from monolithic "ball of mud" systems, but the reality is that, in the vast majority of organizations, different projects and technologies will continue to be developed at different speeds. How to handle the dependencies between these disparate systems with different iteration cycles? Consider the "canoncial problem"...
Nov. 30, 2015 07:00 AM EST Reads: 468
In today’s pharmaceutical supply chain, counterfeit activity is thriving. As pharma companies have expanded target markets and outsourced production over the last decade, the supply chain has become increasingly global, virtual, and vulnerable. Illicit activity has thrived, and patients have suffered, with hundreds of thousands dying each year from counterfeit and contaminated drugs. More than 40 countries have responded with new laws that regulate prescription medications as they travel throug...
Nov. 30, 2015 05:45 AM EST Reads: 315
The Internet of Things is clearly many things: data collection and analytics, wearables, Smart Grids and Smart Cities, the Industrial Internet, and more. Cool platforms like Arduino, Raspberry Pi, Intel's Galileo and Edison, and a diverse world of sensors are making the IoT a great toy box for developers in all these areas. In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists discussed what things are the most important, which will have the most profound...
Nov. 30, 2015 05:30 AM EST Reads: 495
As organizations shift towards IT-as-a-service models, the need for managing & protecting data residing across physical, virtual, and now cloud environments grows with it. CommVault can ensure protection & E-Discovery of your data - whether in a private cloud, a Service Provider delivered public cloud, or a hybrid cloud environment – across the heterogeneous enterprise.
Nov. 30, 2015 05:15 AM EST Reads: 254
Naturally, new and exciting technologies and trends like software defined networking, the Internet of Things and the cloud tend to get the lion’s share of attention these days, including when it comes to security. However, it’s important to never forget that at the center of it all is still the enterprise network. And as evidenced by the ever-expanding landslide of data breaches that could have been prevented or at least their impact lessened by better practicing network security basics, it’s ...
Nov. 30, 2015 04:30 AM EST Reads: 289
PubNub has announced the release of BLOCKS, a set of customizable microservices that give developers a simple way to add code and deploy features for realtime apps.PubNub BLOCKS executes business logic directly on the data streaming through PubNub’s network without splitting it off to an intermediary server controlled by the customer. This revolutionary approach streamlines app development, reduces endpoint-to-endpoint latency, and allows apps to better leverage the enormous scalability of PubNu...
Nov. 30, 2015 04:00 AM EST Reads: 350
Put the word continuous in front of many things and we help define DevOps: continuous delivery, continuous testing, continuous assessment, and there is more. The next BriefingsDirect DevOps thought leadership discussion explores the concept of continuous processes around the development and deployment of applications and systems. Put the word continuous in front of many things and we help define DevOps: continuous delivery, continuous testing, continuous assessment, and there is more.
Nov. 30, 2015 04:00 AM EST Reads: 182
Growth hacking is common for startups to make unheard-of progress in building their business. Career Hacks can help Geek Girls and those who support them (yes, that's you too, Dad!) to excel in this typically male-dominated world. Get ready to learn the facts: Is there a bias against women in the tech / developer communities? Why are women 50% of the workforce, but hold only 24% of the STEM or IT positions? Some beginnings of what to do about it! In her Day 2 Keynote at 17th Cloud Expo, San...
Nov. 30, 2015 04:00 AM EST Reads: 608
In today's enterprise, digital transformation represents organizational change even more so than technology change, as customer preferences and behavior drive end-to-end transformation across lines of business as well as IT. To capitalize on the ubiquitous disruption driving this transformation, companies must be able to innovate at an increasingly rapid pace. Traditional approaches for driving innovation are now woefully inadequate for keeping up with the breadth of disruption and change facin...
Nov. 30, 2015 03:00 AM EST Reads: 515
I recently attended and was a speaker at the 4th International Internet of @ThingsExpo at the Santa Clara Convention Center. I also had the opportunity to attend this event last year and I wrote a blog from that show talking about how the “Enterprise Impact of IoT” was a key theme of last year’s show. I was curious to see if the same theme would still resonate 365 days later and what, if any, changes I would see in the content presented.
Nov. 30, 2015 02:00 AM EST Reads: 451