Welcome!

Microservices Expo Authors: Pat Romanski, Liz McMillan, Stackify Blog, Elizabeth White, Yeshim Deniz

Related Topics: Microservices Expo, @CloudExpo

Microservices Expo: Article

BASE Jumping in the Cloud

Rethinking data consistency

Your CIO is all fired up about moving your legacy inventory management app to the Cloud. Lower capital costs! Dynamic provisioning! Outsourced infrastructure! So you get out your shoehorn, provision some storage and virtual machine instances, and forklift the whole mess into the stratosphere. (OK, there's more to it than that, but bear with me.)

Everything seems to work at first. But then the real test comes: the Holiday season, when you do most of your online business. You breathe a sigh of relief as your Cloud provider seamlessly scales up to meet the spikes in demand. But then your boss calls, irate. Turns out customers are swamping the call center with complaints of failed transactions.

You frantically dive into the log files and diagnostic reports to see what the problem is. Apparently, the database has not been keeping an accurate count of your inventory-which is pretty much what an inventory management system is all about. You check the SQL, and you can't find the problem. Now you're really beginning to sweat.

You dig deeper, and you find the database is frequently in an inconsistent state. When the app processes orders, it decrements the product count. When the count for a product drops to zero, it's supposed to show customers that you've run out. But sometimes, the count is off. Not always, and not for every product. And the problem only seems to occur in the afternoons, when you normally experience your heaviest transaction volume.

The Problem: Consistency in the Cloud
The problem is that while it may appear that your database is running in a single storage partition, in reality the Cloud provider is provisioning multiple physical partitions as needed to provide elastic capacity. But when you look at the fine print in your contract with the Cloud provider, you realize they offer eventual consistency, not immediate consistency. In other words, your data may be inconsistent for short periods of time, especially when your app is experiencing peak load. It may only be a matter of seconds for the issue to resolve, but in the meantime, customers are placing orders for products that aren't available. You're charging their credit cards and all they get for their money is an error page.

From the perspective of the Cloud provider, however, nothing is broken. Eventual consistency is inherent to the nature of Cloud computing, a principle we call the CAP Theorem: no distributed computing system can guarantee (immediate) consistency, availability, and partition tolerance at the same time. You can get any two of these, but not all three at once.

Of these three characteristics, partition tolerance is the least familiar. In essence, a distributed system is partition tolerant when it will continue working even in the case of a partial network failure. In other words, bits and pieces of the system can fail or otherwise stop communicating with the other bits and pieces, and the overall system will continue to function.

With on-premise distributed computing, we're not particularly interested in partition tolerance: transactional environments run in a single partition. If we want ACID transactionality (atomic, consistent, isolated, and durable transactions), then we should stick with a partition intolerant approach like a two-phase commit infrastructure. In essence, ACID implies that a transaction runs in a single partition.

But in the Cloud, we require partition tolerance, because the Cloud provider is willing to allow that each physical instance cannot necessarily communicate with every other physical instance at all times, and each physical instance may go down unpredictably. And if your underlying physical instances aren't communicating or working properly, then you have either an availability or a consistency issue. But since the Cloud is architected for high availability, consistency will necessarily suffer.

The Solution: Rethink Your Priorities
The kneejerk reaction might be that since consistency is nonnegotiable, we need to force the Cloud providers to give up partition tolerance. But in reality, that's entirely the wrong way to think about the problem. Instead, we must rethink our priorities.

As any data specialist will tell you, there are always performance vs. flexibility tradeoffs in the world of data. Every generation of technology suffers from this tradeoff, and the Cloud is no different. What is different about the Cloud is that we want virtualization-based elasticity-which requires partition tolerance.

If we want ACID transactionality then we should stick with an on-premise partition intolerant approach. But in the Cloud, ACID is the wrong priority. We need a different way of thinking about consistency and reliability. Instead of ACID, we need BASE (catchy, eh?)

BASE stands for Basic Availability (supports partial failures without leading to a total system failure), Soft-state (any change in state must be maintained through periodic refreshment), and Eventual consistency (the data will be consistent after a set amount of time passes since an update). BASE has been around for several years and actually predates the notion of Cloud computing; in fact, it underlies the telco world's notion of "best effort" reliability that applies to the mobile phone infrastructure. But today, understanding the principles of BASE is essential to understanding how to architect applications for the Cloud.

Thinking in a BASE Way
Let's put the BASE principles in simple terms.

Basic availability: stuff happens. We're using commodity hardware in the Cloud. We're expecting and planning for failure. But hey, we've got it covered.

Soft state: the squeaky wheel gets the grease. If you don't keep telling me where you are or what you're doing, I'll assume you're not there anymore or you're done doing whatever it is you were doing. So if any part of the infrastructure crashes and reboots, it can bootstrap itself without any worries about it being in the wrong state.

Eventual consistency: It's OK to use stale data some of the time. It'll all come clean eventually. Accountants have followed this principle since Babylonian times. It's called "closing the books."

So, how would you address your inventory app following BASE best effort principles? First, assume that any product quantity is approximate. If the quantity isn't near zero you don't have much of a problem. If it is near zero, set the proper expectation with the customer. Don't charge their credit card in a synchronous fashion. Instead, let them know that their purchase has probably completed successfully. Once the dust settles, let them know if they got the item or not.

Of course, this inventory example is an oversimplification, and every situation is different. The bottom line is that you can't expect the same kind of transactionality in the Cloud as you could in a partition intolerant on-premise environment. If you erroneously assume that you can move your app to the Cloud without reworking how it handles transactionality, then you are in for an unpleasant surprise. On the other hand, rearchitecting your app for the Cloud will improve it overall.

The ZapThink Take
Intermittently stale data? Unpredictable counts? States that expire? Your computer science profs must be rolling around in their graves. That's no way to write a computer program! Data are data, counts are counts, and states are states! How could anything work properly if we get all loosey-goosey about such basics?

Welcome to the twenty-first century, folks. Bank account balances, search engine results, instant messaging buddy lists-if you think about it, all of these everyday elements of our wired lives follow BASE principles in one way or another.

And now we have Cloud computing, where we're bundling together several different modern distributed computing trends into one neat package. But if we mistake the Cloud for being nothing more than a collection of existing trends then we're likely to fall into the "horseless carriage" trap, where we fail to recognize what's special about the Cloud.

The Cloud is much more than a virtual server in the sky. You can't simply migrate an existing app into the Cloud and expect it to work properly, let alone take advantage of the power of the Cloud. Instead, application migration and application modernization necessarily go hand in hand, and architecting your app for the Cloud is more important than ever.

More Stories By Jason Bloomberg

Jason Bloomberg is the leading expert on architecting agility for the enterprise. As president of Intellyx, Mr. Bloomberg brings his years of thought leadership in the areas of Cloud Computing, Enterprise Architecture, and Service-Oriented Architecture to a global clientele of business executives, architects, software vendors, and Cloud service providers looking to achieve technology-enabled business agility across their organizations and for their customers. His latest book, The Agile Architecture Revolution (John Wiley & Sons, 2013), sets the stage for Mr. Bloomberg’s groundbreaking Agile Architecture vision.

Mr. Bloomberg is perhaps best known for his twelve years at ZapThink, where he created and delivered the Licensed ZapThink Architect (LZA) SOA course and associated credential, certifying over 1,700 professionals worldwide. He is one of the original Managing Partners of ZapThink LLC, the leading SOA advisory and analysis firm, which was acquired by Dovel Technologies in 2011. He now runs the successor to the LZA program, the Bloomberg Agile Architecture Course, around the world.

Mr. Bloomberg is a frequent conference speaker and prolific writer. He has published over 500 articles, spoken at over 300 conferences, Webinars, and other events, and has been quoted in the press over 1,400 times as the leading expert on agile approaches to architecture in the enterprise.

Mr. Bloomberg’s previous book, Service Orient or Be Doomed! How Service Orientation Will Change Your Business (John Wiley & Sons, 2006, coauthored with Ron Schmelzer), is recognized as the leading business book on Service Orientation. He also co-authored the books XML and Web Services Unleashed (SAMS Publishing, 2002), and Web Page Scripting Techniques (Hayden Books, 1996).

Prior to ZapThink, Mr. Bloomberg built a diverse background in eBusiness technology management and industry analysis, including serving as a senior analyst in IDC’s eBusiness Advisory group, as well as holding eBusiness management positions at USWeb/CKS (later marchFIRST) and WaveBend Solutions (now Hitachi Consulting).

@MicroservicesExpo Stories
DevOps at Cloud Expo – being held October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA – announces that its Call for Papers is open. Born out of proven success in agile development, cloud computing, and process automation, DevOps is a macro trend you cannot afford to miss. From showcase success stories from early adopters and web-scale businesses, DevOps is expanding to organizations of all sizes, including the world's largest enterprises – and delivering real r...
SYS-CON Events announced today that Fusion, a leading provider of cloud services, 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. Fusion, a leading provider of integrated cloud solutions to small, medium and large businesses, is the industry’s single source for the cloud. Fusion’s advanced, proprietary cloud service platform enables the integration of leading edge solutions in the cloud, including cloud...
There are two main reasons for infrastructure automation. First, system administrators, IT professionals and DevOps engineers need to automate as many routine tasks as possible. That’s why we build tools at Stackify to help developers automate processes like application performance management, error monitoring, and log management; automation means you have more time for mission-critical tasks. Second, automation makes the management of complex, diverse environments possible and allows rapid scal...
Cloud promises the agility required by today’s digital businesses. As organizations adopt cloud based infrastructures and services, their IT resources become increasingly dynamic and hybrid in nature. Managing these require modern IT operations and tools. In his session at 20th Cloud Expo, Raj Sundaram, Senior Principal Product Manager at CA Technologies, will discuss how to modernize your IT operations in order to proactively manage your hybrid cloud and IT environments. He will be sharing bes...
This talk centers around how to automate best practices in a multi-/hybrid-cloud world based on our work with customers like GE, Discovery Communications and Fannie Mae. Today’s enterprises are reaping the benefits of cloud computing, but also discovering many risks and challenges. In the age of DevOps and the decentralization of IT, it’s easy to over-provision resources, forget that instances are running, or unintentionally expose vulnerabilities.
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. In his Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, will explore t...
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...
SYS-CON Events announced today that Peak 10, Inc., a national IT infrastructure and cloud services provider, 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. Peak 10 provides reliable, tailored data center and network services, cloud and managed services. Its solutions are designed to scale and adapt to customers’ changing business needs, enabling them to lower costs, improve performance and focus intern...
SYS-CON Events announced today that Linux Academy, the foremost online Linux and cloud training platform and community, 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. Linux Academy was founded on the belief that providing high-quality, in-depth training should be available at an affordable price. Industry leaders in quality training, provided services, and student certification passes, its goal is to c...
It has never been a better time to be a developer! Thanks to cloud computing, deploying our applications is much easier than it used to be. How we deploy our apps continues to evolve thanks to cloud hosting, Platform-as-a-Service (PaaS), and now Function-as-a-Service. FaaS is the concept of serverless computing via serverless architectures. Software developers can leverage this to deploy an individual "function", action, or piece of business logic. They are expected to start within milliseconds...
We all know that end users experience the internet primarily with mobile devices. From an app development perspective, we know that successfully responding to the needs of mobile customers depends on rapid DevOps – failing fast, in short, until the right solution evolves in your customers' relationship to your business. Whether you’re decomposing an SOA monolith, or developing a new application cloud natively, it’s not a question of using microservices - not doing so will be a path to eventual ...
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 HTBase 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. HTBase (Gartner 2016 Cool Vendor) delivers a Composable IT infrastructure solution architected for agility and increased efficiency. It turns compute, storage, and fabric into fluid pools of resources that are easily composed and re-composed to meet each application’s needs. With HTBase, companies can quickly prov...
@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...
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...
The purpose of this article is draw attention to key SaaS services that are commonly overlooked during contact signing that are essential to ensuring they meet the expectations and requirements of the organization and provide guidance and recommendations for process and controls necessary for achieving quality SaaS contractual agreements.
SYS-CON Events announced today that OpsGenie 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. Founded in 2012, OpsGenie is an alerting and on-call management solution for dev and ops teams. OpsGenie provides the tools needed to design actionable alerts, manage on-call schedules and escalations, and ensure that the right people are notified at the right time, using multiple notification methods.
The first step to solving a problem is recognizing that it actually exists. And whether you've realized it or not, cloud services are a problem for your IT department. Even if you feel like you have a solid grasp of cloud technology and the nuances of making a cloud purchase, business leaders don't share the same confidence. Nearly 80% feel that IT lacks the skills necessary to help with cloud purchases-and they're looking to cloud brokers for help instead. It's time to admit we have a cloud s...
According to a recent Gartner study, by 2020, it will be unlikelythat any enterprise will have a “no cloud” policy, and hybrid will be the most common use of the cloud. While the benefits of leveraging public cloud infrastructures are well understood, the desire to keep critical workloads and data on-premise in the private data center still remains. For enterprises, the hybrid cloud provides a best of both worlds solution. However, the leading factor that determines the preference to the hybrid ...
In this modern world of IT, you've probably got some new colleagues in your life-namely, the cloud and SaaS providers who now hold your infrastructure in their hands. These business relationships-yes, they're technology-based, but cloud and SaaS are business models-will become as important to your IT team and your company as the hardware and software you used to install. Once you've adopted SaaS, or inherited SaaS, it's on you to avoid price hikes, licensing issues and app or provider sprawl....