Click here to close now.


Cloud Security Authors: Pat Romanski, Mike Tierney, Liz McMillan, Cloud Best Practices Network, Teresa Schoch

Related Topics: @CloudExpo, Microservices Expo, Containers Expo Blog, Agile Computing, Cloud Security, @BigDataExpo, SDN Journal

@CloudExpo: Blog Feed Post

Cloud: Impact of DNS on Performance

Developers and operations must work together to mitigate the impact of hybrid architectures on application performance

One of the ramifications of relying on off-premise cloud infrastructure is that you're necessarily stuck with some of the idiosyncrasies that come with it. For example, it's not your network, and thus topologically-related identifiers such as host names and IP address are not within your purview. But you certainly aren't going to ask your customers to visit "". At least not if you want them visit, you won't.

Luckily, you control your own DNS destiny, so you'll just CNAME that crazy long host name provided by the provider to be something more catchy and inline with your branding, say, "".

While certainly more appealing to everyone (easy to remember, fits better on a bumper sticker and on branded swag) it does have a downside: double the latency.

You see, CNAME lookups require two distinct DNS queries to resolve - the first retrieves the ultra-ugly-long host name, the second resolves the ultra-ugly-long host name into an IP address that can actually be used by the browser to connect.

So that's double the lookup, double the roundtrips, double the latency.

Of course, no web page comprises just one host. That would be so 90s and this, this is the 21st century! This is Web 2.0, the age of integration and interconnection and inter-everything. And if the services upon which you rely to build that web app are using CNAMEs, too, well... I hope you like math cause you're going to be added up some roundtrips and latency for a while.

The point here is not to scare you off of hybrid architectures due to the potential impact on performance, but rather to remind you to keep the impact in the fore. It is important to remember the impact of topology, proximity, and the technology in general on the overall performance of your web applications.

A Google Developers article nails down where DNS latency comes from quite well:

There are two components to DNS latency:

  • - Latency between the client (user) and DNS resolving server. In most cases this is largely due to the usual round-trip time (RTT) constraints in networked systems: geographical distance between client and server machines; network congestion; packet loss and long retransmit delays (one second on average); overloaded servers, denial-of-service attacks and so on.
  • - Latency between resolving servers and other nameservers. This source of latency is caused primarily by the following factors:
    • - Cache misses. If a response cannot be served from a resolver's cache, but requires recursively querying other nameservers, the added network latency is considerable, especially if the authoritative servers are geographically remote.
    • - Underprovisioning. If DNS resolvers are overloaded, they must queue DNS resolution requests and responses, and may begin dropping and retransmitting packets.
    • - Malicious traffic. Even if a DNS service is overprovisioned, DoS traffic can place undue load on the servers. Similarly, Kaminsky-style attacks can involve flooding resolvers with queries that are guaranteed to bypass the cache and require outgoing requests for resolution.

-- Introduction: causes and mitigations of DNS latency

Interestingly, Google is arguing for public DNS services, even though this may in fact contribute to location-induced DNS latency, particularly for custom domains for which the authoritative zone is served by relatively few number of DNS servers, most of which are geographically located far from the majority of users. Intercontinental latency is still very much problematic.

Catchpoint, a web performance monitoring service, mentions this in its exhaustive list of the ways in which DNS impacts performance:

Exotic Domains: be careful with the exotic domain names, .ly, .tv… these domains have authoritative servers that are often far away from you end user ISPs. The records will have almost always 2 day TTL, however you never know when someone will be impacted because the query has to go to the authoritative servers and they fail. Example “.ly”, 2 authoritative servers are in Libya, 2 in the US, and 1 in the Netherlands.

So when we go connecting clouds and data centers, we need to be concerned with where and how domains are being disseminated, sharded, and resolved. We need to more carefully consider how we are referencing content and whether or not the performance boosts we get from some techniques (such as domain sharding) are being offset by the impact of double the latency from the need to resolve those extra hosts.

We need to examine that in the context of other contributing factors, such as TTL (time to live). If the time to live is long enough, then perhaps the initial hit from the extra lookup required to resolve a CNAME isn't going to matter over the life of the session. If we're looking at supporting a stateless API in which sessions don't really exist, then the second lookup may indeed be problematic, but only if the calls are generally spread out over a time interval that is greater than the TTL.

It's a balancing act, where understanding how application network services contribute to the performance of applications is critical to pushing the right buttons and twisting the right knobs will alleviate performance issues that can damage adoption and growth of the web applications that are key to business.

You're Not Off The Hook, Developers

So often it's the case that applications are written with a specific behavior in mind and it is left to devops to figure out how to mitigate these kinds of potential performance issues. But it is just as important for developers to understand how the application network services contribute to performance because sometimes, all it takes is for the application to be "tweaked' with respect to an update interval or use of a different host name to generate a significant improvement in performance. It is increasingly difficult for - and sometimes even impossible - for operations to make adjustments in the infrastructure, particularly in hybrid environments where infrastructure services are black-box and off-limits.

Thus, it is of growing importance that developers and operations work together to map the interaction of applications with application network services such that each group can make appropriate modifications and configuration changes that serve to improve the overall performance of the application, no matter where it might be deployed.

As more and more organizations adopt hybrid, distributed applications that span geographies in addition to environments, this level of cooperation and collaboration will be key to managing web application performance issues.

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
Today air travel is a minefield of delays, hassles and customer disappointment. Airlines struggle to revitalize the experience. GE and M2Mi will demonstrate practical examples of how IoT solutions are helping airlines bring back personalization, reduce trip time and improve reliability. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Dr. Sarah Cooper, M2Mi's VP Business Development and Engineering, will explore the IoT cloud-based platform technologies driving this change including privacy controls, data transparency and integration of real time context w...
Electric power utilities face relentless pressure on their financial performance, and reducing distribution grid losses is one of the last untapped opportunities to meet their business goals. Combining IoT-enabled sensors and cloud-based data analytics, utilities now are able to find, quantify and reduce losses faster – and with a smaller IT footprint. Solutions exist using Internet-enabled sensors deployed temporarily at strategic locations within the distribution grid to measure actual line loads.
The buzz continues for cloud, data analytics and the Internet of Things (IoT) and their collective impact across all industries. But a new conversation is emerging - how do companies use industry disruption and technology enablers to lead in markets undergoing change, uncertainty and ambiguity? Organizations of all sizes need to evolve and transform, often under massive pressure, as industry lines blur and merge and traditional business models are assaulted and turned upside down. In this new data-driven world, marketplaces reign supreme while interoperability, APIs and applications deliver un...
The Internet of Everything is re-shaping technology trends–moving away from “request/response” architecture to an “always-on” Streaming Web where data is in constant motion and secure, reliable communication is an absolute necessity. As more and more THINGS go online, the challenges that developers will need to address will only increase exponentially. In his session at @ThingsExpo, Todd Greene, Founder & CEO of PubNub, will explore the current state of IoT connectivity and review key trends and technology requirements that will drive the Internet of Things from hype to reality.
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 shows "less than 10 percent of IoT developers are making enough to support a reasonably sized team....
Too often with compelling new technologies market participants become overly enamored with that attractiveness of the technology and neglect underlying business drivers. This tendency, what some call the “newest shiny object syndrome,” is understandable given that virtually all of us are heavily engaged in technology. But it is also mistaken. Without concrete business cases driving its deployment, IoT, like many other technologies before it, will fade into obscurity.
You have your devices and your data, but what about the rest of your Internet of Things story? Two popular classes of technologies that nicely handle the Big Data analytics for Internet of Things are Apache Hadoop and NoSQL. Hadoop is designed for parallelizing analytical work across many servers and is ideal for the massive data volumes you create with IoT devices. NoSQL databases such as Apache HBase are ideal for storing and retrieving IoT data as “time series data.”
The IoT market is on track to hit $7.1 trillion in 2020. The reality is that only a handful of companies are ready for this massive demand. There are a lot of barriers, paint points, traps, and hidden roadblocks. How can we deal with these issues and challenges? The paradigm has changed. Old-style ad-hoc trial-and-error ways will certainly lead you to the dead end. What is mandatory is an overarching and adaptive approach to effectively handle the rapid changes and exponential growth.
Today’s connected world is moving from devices towards things, what this means is that by using increasingly low cost sensors embedded in devices we can create many new use cases. These span across use cases in cities, vehicles, home, offices, factories, retail environments, worksites, health, logistics, and health. These use cases rely on ubiquitous connectivity and generate massive amounts of data at scale. These technologies enable new business opportunities, ways to optimize and automate, along with new ways to engage with users.
The IoT is upon us, but today’s databases, built on 30-year-old math, require multiple platforms to create a single solution. Data demands of the IoT require Big Data systems that can handle ingest, transactions and analytics concurrently adapting to varied situations as they occur, with speed at scale. In his session at @ThingsExpo, Chad Jones, chief strategy officer at Deep Information Sciences, will look differently at IoT data so enterprises can fully leverage their IoT potential. He’ll share tips on how to speed up business initiatives, harness Big Data and remain one step ahead by apply...
There will be 20 billion IoT devices connected to the Internet soon. What if we could control these devices with our voice, mind, or gestures? What if we could teach these devices how to talk to each other? What if these devices could learn how to interact with us (and each other) to make our lives better? What if Jarvis was real? How can I gain these super powers? In his session at 17th Cloud Expo, Chris Matthieu, co-founder and CTO of Octoblu, will show you!
SYS-CON Events announced today that ProfitBricks, the provider of painless cloud infrastructure, will exhibit at SYS-CON's 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. ProfitBricks is the IaaS provider that offers a painless cloud experience for all IT users, with no learning curve. ProfitBricks boasts flexible cloud servers and networking, an integrated Data Center Designer tool for visual control over the cloud and the best price/performance value available. ProfitBricks was named one of the coolest Clo...
As a company adopts a DevOps approach to software development, what are key things that both the Dev and Ops side of the business must keep in mind to ensure effective continuous delivery? In his session at DevOps Summit, Mark Hydar, Head of DevOps, Ericsson TV Platforms, will share best practices and provide helpful tips for Ops teams to adopt an open line of communication with the development side of the house to ensure success between the two sides.
SYS-CON Events announced today that IBM Cloud Data Services has been named “Bronze Sponsor” of SYS-CON's 17th Cloud Expo, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA. IBM Cloud Data Services offers a portfolio of integrated, best-of-breed cloud data services for developers focused on mobile computing and analytics use cases.
SYS-CON Events announced today that Sandy Carter, IBM General Manager Cloud Ecosystem and Developers, and a Social Business Evangelist, will keynote at the 17th International Cloud Expo®, which will take place on November 3–5, 2015, at the Santa Clara Convention Center in Santa Clara, CA.
Developing software for the Internet of Things (IoT) comes with its own set of challenges. Security, privacy, and unified standards are a few key issues. In addition, each IoT product is comprised of at least three separate application components: the software embedded in the device, the backend big-data service, and the mobile application for the end user's controls. Each component is developed by a different team, using different technologies and practices, and deployed to a different stack/target - this makes the integration of these separate pipelines and the coordination of software upd...
Mobile messaging has been a popular communication channel for more than 20 years. Finnish engineer Matti Makkonen invented the idea for SMS (Short Message Service) in 1984, making his vision a reality on December 3, 1992 by sending the first message ("Happy Christmas") from a PC to a cell phone. Since then, the technology has evolved immensely, from both a technology standpoint, and in our everyday uses for it. Originally used for person-to-person (P2P) communication, i.e., Sally sends a text message to Betty – mobile messaging now offers tremendous value to businesses for customer and empl...
"Matrix is an ambitious open standard and implementation that's set up to break down the fragmentation problems that exist in IP messaging and VoIP communication," explained John Woolf, Technical Evangelist at Matrix, in this interview at @ThingsExpo, held Nov 4–6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
WebRTC converts the entire network into a ubiquitous communications cloud thereby connecting anytime, anywhere through any point. In his session at WebRTC Summit,, Mark Castleman, EIR at Bell Labs and Head of Future X Labs, will discuss how the transformational nature of communications is achieved through the democratizing force of WebRTC. WebRTC is doing for voice what HTML did for web content.
The broad selection of hardware, the rapid evolution of operating systems and the time-to-market for mobile apps has been so rapid that new challenges for developers and engineers arise every day. Security, testing, hosting, and other metrics have to be considered through the process. In his session at Big Data Expo, Walter Maguire, Chief Field Technologist, HP Big Data Group, at Hewlett-Packard, will discuss the challenges faced by developers and a composite Big Data applications builder, focusing on how to help solve the problems that developers are continuously battling.