Welcome!

Cloud Security Authors: Shelly Palmer, Elizabeth White, Liz McMillan, Ravi Rajamiyer, Stackify Blog

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 "host111-east-virginia-zone3-subnet5.cloudproivder.com". 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, "coolappz.com".

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
SYS-CON Events announced today that N3N will exhibit at SYS-CON's @ThingsExpo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. N3N’s solutions increase the effectiveness of operations and control centers, increase the value of IoT investments, and facilitate real-time operational decision making. N3N enables operations teams with a four dimensional digital “big board” that consolidates real-time live video feeds alongside IoT sensor data a...
Mobile device usage has increased exponentially during the past several years, as consumers rely on handhelds for everything from news and weather to banking and purchases. What can we expect in the next few years? The way in which we interact with our devices will fundamentally change, as businesses leverage Artificial Intelligence. We already see this taking shape as businesses leverage AI for cost savings and customer responsiveness. This trend will continue, as AI is used for more sophistica...
Real IoT production deployments running at scale are collecting sensor data from hundreds / thousands / millions of devices. The goal is to take business-critical actions on the real-time data and find insights from stored datasets. In his session at @ThingsExpo, John Walicki, Watson IoT Developer Advocate at IBM Cloud, will provide a fast-paced developer journey that follows the IoT sensor data from generation, to edge gateway, to edge analytics, to encryption, to the IBM Bluemix cloud, to Wa...
What is the best strategy for selecting the right offshore company for your business? In his session at 21st Cloud Expo, Alan Winters, U.S. Head of Business Development at MobiDev, will discuss the things to look for - positive and negative - in evaluating your options. He will also discuss how to maximize productivity with your offshore developers. Before you start your search, clearly understand your business needs and how that impacts software choices.
SYS-CON Events announced today that Fusic will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Fusic Co. provides mocks as virtual IoT devices. You can customize mocks, and get any amount of data at any time in your test. For more information, visit https://fusic.co.jp/english/.
SYS-CON Events announced today that Massive Networks, that helps your business operate seamlessly with fast, reliable, and secure internet and network solutions, has been named "Exhibitor" of SYS-CON's 21st International Cloud Expo ®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. As a premier telecommunications provider, Massive Networks is headquartered out of Louisville, Colorado. With years of experience under their belt, their team of...
SYS-CON Events announced today that Enroute Lab will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Enroute Lab is an industrial design, research and development company of unmanned robotic vehicle system. For more information, please visit http://elab.co.jp/.
SYS-CON Events announced today that MIRAI Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. MIRAI Inc. are IT consultants from the public sector whose mission is to solve social issues by technology and innovation and to create a meaningful future for people.
SYS-CON Events announced today that Mobile Create USA will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Mobile Create USA Inc. is an MVNO-based business model that uses portable communication devices and cellular-based infrastructure in the development, sales, operation and mobile communications systems incorporating GPS capabi...
There is huge complexity in implementing a successful digital business that requires efficient on-premise and cloud back-end infrastructure, IT and Internet of Things (IoT) data, analytics, Machine Learning, Artificial Intelligence (AI) and Digital Applications. In the data center alone, there are physical and virtual infrastructures, multiple operating systems, multiple applications and new and emerging business and technological paradigms such as cloud computing and XaaS. And then there are pe...
SYS-CON Events announced today that Interface Corporation will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Interface Corporation is a company developing, manufacturing and marketing high quality and wide variety of industrial computers and interface modules such as PCIs and PCI express. For more information, visit http://www.i...
SYS-CON Events announced today that Keisoku Research Consultant Co. will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Keisoku Research Consultant, Co. offers research and consulting in a wide range of civil engineering-related fields from information construction to preservation of cultural properties. For more information, vi...
SYS-CON Events announced today that SIGMA Corporation will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. uLaser flow inspection device from the Japanese top share to Global Standard! Then, make the best use of data to flip to next page. For more information, visit http://www.sigma-k.co.jp/en/.
SYS-CON Events announced today that B2Cloud will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. B2Cloud specializes in IoT devices for preventive and predictive maintenance in any kind of equipment retrieving data like Energy consumption, working time, temperature, humidity, pressure, etc.
Agile has finally jumped the technology shark, expanding outside the software world. Enterprises are now increasingly adopting Agile practices across their organizations in order to successfully navigate the disruptive waters that threaten to drown them. In our quest for establishing change as a core competency in our organizations, this business-centric notion of Agile is an essential component of Agile Digital Transformation. In the years since the publication of the Agile Manifesto, the conn...
While some developers care passionately about how data centers and clouds are architected, for most, it is only the end result that matters. To the majority of companies, technology exists to solve a business problem, and only delivers value when it is solving that problem. 2017 brings the mainstream adoption of containers for production workloads. In his session at 21st Cloud Expo, Ben McCormack, VP of Operations at Evernote, will discuss how data centers of the future will be managed, how th...
SYS-CON Events announced today that NetApp has been named “Bronze Sponsor” of SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. NetApp is the data authority for hybrid cloud. NetApp provides a full range of hybrid cloud data services that simplify management of applications and data across cloud and on-premises environments to accelerate digital transformation. Together with their partners, NetApp em...
SYS-CON Events announced today that Nihon Micron will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Nihon Micron Co., Ltd. strives for technological innovation to establish high-density, high-precision processing technology for providing printed circuit board and metal mount RFID tags used for communication devices. For more inf...
SYS-CON Events announced today that Suzuki Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Suzuki Inc. is a semiconductor-related business, including sales of consuming parts, parts repair, and maintenance for semiconductor manufacturing machines, etc. It is also a health care business providing experimental research for...
SYS-CON Events announced today that Ryobi Systems will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Ryobi Systems Co., Ltd., as an information service company, specialized in business support for local governments and medical industry. We are challenging to achive the precision farming with AI. For more information, visit http:...