Welcome!

Microsoft Cloud Authors: Lori MacVittie, Elizabeth White, Yeshim Deniz, Serafima Al, Janakiram MSV

Related Topics: @CloudExpo, Microservices Expo, Containers Expo Blog, Machine Learning , Agile Computing

@CloudExpo: Blog Feed Post

The Limits of Cloud: Gratuitous ARP and Failover

Understanding the limitations of cloud will better enable a successful migration strategy

Cloud is great at many things. At other things, not so much. Understanding the limitations of cloud will better enable a successful migration strategy.

One of the truisms of technology is that takes a few years of adoption before folks really start figuring out what it excels at – and conversely what it doesn't. That's generally because early adoption is focused on lab-style experimentation that rarely extends beyond basic needs.

It's when adoption reaches critical mass and folks start trying to use the technology to implement more advanced architectures that the "gotchas" start to be discovered.

Cloud is no exception.

whatclouddoesrightandwrong

 

A few of the things we've learned over the past years of adoption is that cloud is always on, it's simple to manage, and it makes applications and infrastructure services easy to scale.

Some of the things we're learning now is that cloud isn't so great at supporting application mobility, monitoring of deployed services and at providing advanced networking capabilities.

The reason that last part is so important is that a variety of enterprise-class capabilities we've come to rely upon are ultimately enabled by some of the advanced networking techniques cloud simply does not support.

Take gratuitous ARP, for example. Most cloud providers do not allow or support this feature which ultimately means an inability to take advantage of higher-level functions traditionally taken for granted in the enterprise – like failover.

GRATUITOUS ARP and ITS IMPLICATIONS

For those unfamiliar with gratuitous ARP let's get you familiar with it quickly. A gratuitous ARP is an unsolicited ARP request made by a network element (host, switch, device, etc… ) to resolve its own IP address. The source and destination IP address are identical to the source IP address assigned to the network element. The destination MAC is a broadcast address. Gratuitous ARP is used for a variety of reasons. For example, if there is an ARP reply to the request, it means there exists an IP conflict. When a system first boots up, it will often send a gratuitous ARP to indicate it is "up" and available. And finally, it is used as the basis for load balancing failover. To ensure availability of load balancing services, two load balancers will share an IP address (often referred to as a floating IP). Upstream devices recognize the "primary" device by means of a simple ARP entry associating the floating IP with the active device. If the active device fails, the secondary immediately notices (due to heartbeat monitoring between the two) and will send out a gratuitous ARP indicating it is now associated with the IP address and won't the rest of the network please send subsequent traffic to it rather than the failed primary. VRRP and HSRP may also use gratuitous ARP to implement router failover.   how-failure-lb-works

Most cloud environments do not allow broadcast traffic of this nature. After all, it's practically guaranteed that you are sharing a network segment with other tenants, and thus broadcasting traffic could certainly disrupt other tenant's traffic. Additionally, as security minded folks will be eager to remind us, it is fairly well-established that the default for accepting gratuitous ARPs on the network should be "don't do it".

The astute observer will realize the reason for this; there is no security, no ability to verify, no authentication, nothing. A network element configured to accept gratuitous ARPs does so at the risk of being tricked into trusting, explicitly, every gratuitous ARP – even those that may be attempting to fool the network into believing it is a device it is not supposed to be.

That, in essence, is ARP poisoning, and it's one of the security risks associated with the use of gratuitous ARP. Granted, someone needs to be physically on the network to pull this off, but in a cloud environment that's not nearly as difficult as it might be on a locked down corporate network. Gratuitous ARP can further be used to execute denial of service, man in the middle and MAC flooding attacks. None of which have particularly pleasant outcomes, especially in a cloud environment where such attacks would be against shared infrastructure, potentially impacting many tenants.

Thus cloud providers are understandably leery about allowing network elements to willy-nilly announce their own IP addresses.

That said, most enterprise-class network elements have implemented protections against these attacks precisely because of the reliance on gratuitous ARP for various infrastructure services. Most of these protections use a technique that will tentatively accept a gratuitous ARP, but not enter it in its ARP cache unless it has a valid IP-to-MAC mapping, as defined by the device configuration. Validation can take the form of matching against DHCP-assigned addresses or existence in a trusted database.

Obviously these techniques would put an undue burden on a cloud provider's network given that any IP address on a network segment might be assigned to a very large set of MAC addresses.

Simply put, gratuitous ARP is not cloud-friendly, and thus it is you will be hard pressed to find a cloud provider that supports it.

What does that mean?

That means, ultimately, that failover mechanisms in the cloud cannot be based on traditional techniques unless a means to replicate gratuitous ARP functionality without its negative implications can be designed.

Which means, unfortunately, that traditional failover architectures – even using enterprise-class load balancers in cloud environments – cannot really be implemented today. What that means for IT preparing to migrate business critical applications and services to cloud environments is a careful review of their requirements and of the cloud environment's capabilities to determine whether availability and uptime goals can – or cannot – be met using a combination of cloud and traditional load balancing services.

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.

@ThingsExpo Stories
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at Cloud Expo, Ed Featherston, a director and senior enterprise architect at Collaborative Consulting, discussed the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
IoT is rapidly becoming mainstream as more and more investments are made into the platforms and technology. As this movement continues to expand and gain momentum it creates a massive wall of noise that can be difficult to sift through. Unfortunately, this inevitably makes IoT less approachable for people to get started with and can hamper efforts to integrate this key technology into your own portfolio. There are so many connected products already in place today with many hundreds more on the h...
When shopping for a new data processing platform for IoT solutions, many development teams want to be able to test-drive options before making a choice. Yet when evaluating an IoT solution, it’s simply not feasible to do so at scale with physical devices. Building a sensor simulator is the next best choice; however, generating a realistic simulation at very high TPS with ease of configurability is a formidable challenge. When dealing with multiple application or transport protocols, you would be...
Detecting internal user threats in the Big Data eco-system is challenging and cumbersome. Many organizations monitor internal usage of the Big Data eco-system using a set of alerts. This is not a scalable process given the increase in the number of alerts with the accelerating growth in data volume and user base. Organizations are increasingly leveraging machine learning to monitor only those data elements that are sensitive and critical, autonomously establish monitoring policies, and to detect...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life settl...
In his session at @ThingsExpo, Dr. Robert Cohen, an economist and senior fellow at the Economic Strategy Institute, presented the findings of a series of six detailed case studies of how large corporations are implementing IoT. The session explored how IoT has improved their economic performance, had major impacts on business models and resulted in impressive ROIs. The companies covered span manufacturing and services firms. He also explored servicification, how manufacturing firms shift from se...
DevOpsSummit New York 2018, colocated with CloudEXPO | DXWorldEXPO New York 2018 will be held November 11-13, 2018, in New York City. Digital Transformation (DX) is a major focus with the introduction of DXWorldEXPO within the program. Successful transformation requires a laser focus on being data-driven and on using all the tools available that enable transformation if they plan to survive over the long term. A total of 88% of Fortune 500 companies from a generation ago are now out of bus...
The Jevons Paradox suggests that when technological advances increase efficiency of a resource, it results in an overall increase in consumption. Writing on the increased use of coal as a result of technological improvements, 19th-century economist William Stanley Jevons found that these improvements led to the development of new ways to utilize coal. In his session at 19th Cloud Expo, Mark Thiele, Chief Strategy Officer for Apcera, compared the Jevons Paradox to modern-day enterprise IT, examin...
IoT solutions exploit operational data generated by Internet-connected smart “things” for the purpose of gaining operational insight and producing “better outcomes” (for example, create new business models, eliminate unscheduled maintenance, etc.). The explosive proliferation of IoT solutions will result in an exponential growth in the volume of IoT data, precipitating significant Information Governance issues: who owns the IoT data, what are the rights/duties of IoT solutions adopters towards t...
Amazon started as an online bookseller 20 years ago. Since then, it has evolved into a technology juggernaut that has disrupted multiple markets and industries and touches many aspects of our lives. It is a relentless technology and business model innovator driving disruption throughout numerous ecosystems. Amazon’s AWS revenues alone are approaching $16B a year making it one of the largest IT companies in the world. With dominant offerings in Cloud, IoT, eCommerce, Big Data, AI, Digital Assista...
Organizations planning enterprise data center consolidation and modernization projects are faced with a challenging, costly reality. Requirements to deploy modern, cloud-native applications simultaneously with traditional client/server applications are almost impossible to achieve with hardware-centric enterprise infrastructure. Compute and network infrastructure are fast moving down a software-defined path, but storage has been a laggard. Until now.
Digital Transformation is much more than a buzzword. The radical shift to digital mechanisms for almost every process is evident across all industries and verticals. This is often especially true in financial services, where the legacy environment is many times unable to keep up with the rapidly shifting demands of the consumer. The constant pressure to provide complete, omnichannel delivery of customer-facing solutions to meet both regulatory and customer demands is putting enormous pressure on...
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
DXWorldEXPO LLC announced today that All in Mobile, a mobile app development company from Poland, will exhibit at the 22nd International CloudEXPO | DXWorldEXPO. All In Mobile is a mobile app development company from Poland. Since 2014, they maintain passion for developing mobile applications for enterprises and startups worldwide.
"Akvelon is a software development company and we also provide consultancy services to folks who are looking to scale or accelerate their engineering roadmaps," explained Jeremiah Mothersell, Marketing Manager at Akvelon, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
IoT is at the core or many Digital Transformation initiatives with the goal of re-inventing a company's business model. We all agree that collecting relevant IoT data will result in massive amounts of data needing to be stored. However, with the rapid development of IoT devices and ongoing business model transformation, we are not able to predict the volume and growth of IoT data. And with the lack of IoT history, traditional methods of IT and infrastructure planning based on the past do not app...
DXWorldEXPO LLC announced today that the upcoming DXWorldEXPO | CloudEXPO New York event will feature 10 companies from Poland to participate at the "Poland Digital Transformation Pavilion" on November 12-13, 2018.
22nd International Cloud Expo, taking place June 5-7, 2018, at the Javits Center in New York City, NY, and co-located with the 1st DXWorld Expo will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud ...
@DevOpsSummit at Cloud Expo, taking place November 12-13 in New York City, NY, is co-located with 22nd international CloudEXPO | first international DXWorldEXPO and will feature technical sessions from a rock star conference faculty and the leading industry players in the world.
More and more brands have jumped on the IoT bandwagon. We have an excess of wearables – activity trackers, smartwatches, smart glasses and sneakers, and more that track seemingly endless datapoints. However, most consumers have no idea what “IoT” means. Creating more wearables that track data shouldn't be the aim of brands; delivering meaningful, tangible relevance to their users should be. We're in a period in which the IoT pendulum is still swinging. Initially, it swung toward "smart for smart...