|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.
"Plutora provides release and testing environment capabilities to the enterprise," explained Dalibor Siroky, Director and Co-founder of Plutora, in this SYS-CON.tv interview at @DevOpsSummit, held June 9-11, 2015, at the Javits Center in New York City.
Feb. 20, 2017 09:15 PM EST Reads: 4,468
You often hear the two titles of "DevOps" and "Immutable Infrastructure" used independently. In his session at DevOps Summit, John Willis, Technical Evangelist for Docker, covered the union between the two topics and why this is important. He provided an overview of Immutable Infrastructure then showed how an Immutable Continuous Delivery pipeline can be applied as a best practice for "DevOps." He ended the session with some interesting case study examples.
Feb. 20, 2017 05:45 PM EST Reads: 4,005
When you focus on a journey from up-close, you look at your own technical and cultural history and how you changed it for the benefit of the customer. This was our starting point: too many integration issues, 13 SWP days and very long cycles. It was evident that in this fast-paced industry we could no longer afford this reality. We needed something that would take us beyond reducing the development lifecycles, CI and Agile methodologies. We made a fundamental difference, even changed our culture...
Feb. 20, 2017 05:30 PM EST Reads: 2,237
2016 has been an amazing year for Docker and the container industry. We had 3 major releases of Docker engine this year , and tremendous increase in usage. The community has been following along and contributing amazing Docker resources to help you learn and get hands-on experience. Here’s some of the top read and viewed content for the year. Of course releases are always really popular, particularly when they fit requests we had from the community.
Feb. 20, 2017 02:15 PM EST Reads: 2,690
SYS-CON Events announced today that CA Technologies has been named “Platinum 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, and the 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 ...
Feb. 20, 2017 02:15 PM EST Reads: 1,100
The rise of containers and microservices has skyrocketed the rate at which new applications are moved into production environments today. While developers have been deploying containers to speed up the development processes for some time, there still remain challenges with running microservices efficiently. Most existing IT monitoring tools don’t actually maintain visibility into the containers that make up microservices. As those container applications move into production, some IT operations t...
Feb. 20, 2017 01:30 PM EST Reads: 222
Containers have changed the mind of IT in DevOps. They enable developers to work with dev, test, stage and production environments identically. Containers provide the right abstraction for microservices and many cloud platforms have integrated them into deployment pipelines. DevOps and Containers together help companies to achieve their business goals faster and more effectively. In his session at DevOps Summit, Ruslan Synytsky, CEO and Co-founder of Jelastic, reviewed the current landscape of D...
Feb. 20, 2017 01:00 PM EST Reads: 5,857
SYS-CON Events announced today that Outlyer, a monitoring service for DevOps and operations teams, 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. Outlyer is a monitoring service for DevOps and Operations teams running Cloud, SaaS, Microservices and IoT deployments. Designed for today's dynamic environments that need beyond cloud-scale monitoring, we make monitoring effortless so you...
Feb. 20, 2017 12:45 PM EST Reads: 1,026
Cloud Expo, Inc. has announced today that Andi Mann and Aruna Ravichandran have been named Co-Chairs of @DevOpsSummit at Cloud Expo 2017. The @DevOpsSummit at Cloud Expo New York will take place on June 6-8, 2017, at the Javits Center in New York City, New York, and @DevOpsSummit at Cloud Expo Silicon Valley will take place Oct. 31-Nov. 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Feb. 20, 2017 12:45 PM EST Reads: 966
Microservices (μServices) are a fascinating evolution of the Distributed Object Computing (DOC) paradigm. Initial design of DOC attempted to solve the problem of simplifying developing complex distributed applications by applying object-oriented design principles to disparate components operating across networked infrastructure. In this model, DOC “hid” the complexity of making this work from the developer regardless of the deployment architecture through the use of complex frameworks, such as C...
Feb. 20, 2017 11:30 AM EST Reads: 356
With 10 simultaneous tracks, keynotes, general sessions and targeted breakout classes, Cloud Expo and @ThingsExpo are two of the most important technology events of the year. Since its launch over eight years ago, Cloud Expo and @ThingsExpo have presented a rock star faculty as well as showcased hundreds of sponsors and exhibitors! In this blog post, I provide 7 tips on how, as part of our world-class faculty, you can deliver one of the most popular sessions at our events. But before reading the...
Feb. 20, 2017 11:15 AM EST Reads: 7,874
@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...
Feb. 20, 2017 11:00 AM EST Reads: 859
Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? In this Power Panel at DevOps Summit, moderated by Jason Bloomberg, the leading expert on architecting agility for the enterprise and president of Intellyx, panelists peeled away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud enviro...
Feb. 20, 2017 10:45 AM EST Reads: 5,991
TechTarget storage websites are the best online information resource for news, tips and expert advice for the storage, backup and disaster recovery markets. By creating abundant, high-quality editorial content across more than 140 highly targeted technology-specific websites, TechTarget attracts and nurtures communities of technology buyers researching their companies' information technology needs. By understanding these buyers' content consumption behaviors, TechTarget creates the purchase inte...
Feb. 20, 2017 10:15 AM EST Reads: 909
@DevOpsSummit has been named the ‘Top DevOps Influencer' by iTrend. iTrend processes millions of conversations, tweets, interactions, news articles, press releases, blog posts - and extract meaning form them and analyzes mobile and desktop software platforms used to communicate, various metadata (such as geo location), and automation tools. In overall placement, @DevOpsSummit ranked as the number one ‘DevOps Influencer' followed by @CloudExpo at third, and @MicroservicesE at 24th.
Feb. 20, 2017 09:00 AM EST Reads: 7,826
In his session at @DevOpsSummit at 19th Cloud Expo, Robert Doyle, lead architect at eCube Systems, will examine the issues and need for an agile infrastructure and show the advantages of capturing developer knowledge in an exportable file for migration into production. He will introduce the use of NXTmonitor, a next-generation DevOps tool that captures application environments, dependencies and start/stop procedures in a portable configuration file with an easy-to-use GUI. In addition to captur...
Feb. 20, 2017 07:15 AM EST Reads: 3,386
Both SaaS vendors and SaaS buyers are going “all-in” to hyperscale IaaS platforms such as AWS, which is disrupting the SaaS value proposition. Why should the enterprise SaaS consumer pay for the SaaS service if their data is resident in adjacent AWS S3 buckets? If both SaaS sellers and buyers are using the same cloud tools, automation and pay-per-transaction model offered by IaaS platforms, then why not host the “shrink-wrapped” software in the customers’ cloud? Further, serverless computing, cl...
Feb. 20, 2017 06:00 AM EST Reads: 1,620
The Software Defined Data Center (SDDC), which enables organizations to seamlessly run in a hybrid cloud model (public + private cloud), is here to stay. IDC estimates that the software-defined networking market will be valued at $3.7 billion by 2016. Security is a key component and benefit of the SDDC, and offers an opportunity to build security 'from the ground up' and weave it into the environment from day one. In his session at 16th Cloud Expo, Reuven Harrison, CTO and Co-Founder of Tufin, ...
Feb. 20, 2017 05:30 AM EST Reads: 4,586
Thanks to Docker and the DevOps revolution, microservices have emerged as the new way to build and deploy applications — and there are plenty of great reasons to embrace the microservices trend. If you are going to adopt microservices, you also have to understand that microservice architectures have many moving parts. When it comes to incident management, this presents an important difference between microservices and monolithic architectures. More moving parts mean more complexity to monitor an...
Feb. 20, 2017 01:00 AM EST Reads: 1,135
All organizations that did not originate this moment have a pre-existing culture as well as legacy technology and processes that can be more or less amenable to DevOps implementation. That organizational culture is influenced by the personalities and management styles of Executive Management, the wider culture in which the organization is situated, and the personalities of key team members at all levels of the organization. This culture and entrenched interests usually throw a wrench in the work...
Feb. 20, 2017 12:45 AM EST Reads: 2,409