Welcome!

Release Management Authors: David H Deans, Liz McMillan, Jnan Dash, Lori MacVittie, Gilad Parann-Nissany

Related Topics: @DevOpsSummit, Linux Containers, Containers Expo Blog

@DevOpsSummit: Blog Post

Glue Records and Why They Are Crucial | @DevOpsSummit #DevOps #WebPerf

A lot has been written and discussed about Domain Name System (DNS) in the past few days

Glue Records and Why They Are Crucial
By Nilabh Mishra

A lot has been written and discussed about Domain Name System (DNS) in the past few days. The DDoS attacks on one of the major managed DNS Providers a while ago just made us all take DNS issues seriously once again.

So why so much emphasis on getting DNS Right? Like a lot of other people in this Ecosystem, we believe that DNS is not just a metric but a lifeline; a backbone for our online systems. It is extremely important to the Internet as it lays the foundation for the WWW (World Wide Web).

DNS, in simple terms, translates Host names to IP Addresses. The objective of DNS seems straight forward and simple, yet in real life, it has grown to become one of the most complex systems we have today.

All these add more complexity to an already complex system.

  • Domain Registries
  • Global Top Level Domains (gTLDs)
  • Numerous Country Code Top Level Domains (ccTLDs)
  • An ever-growing list of all the new TLDs (.space, .photography etc.)

Since DNS is not restricted to a single machine (being a distributed, coherent, and hierarchical database) and involves multiple hierarchies and entities, ensuring that every hierarchy and entity involved in managing the system is working efficiently becomes crucial. At the top of the hierarchy is:

  • Root(.)
  • gTLD servers
  • Authoritative Nameservers for domains

Every level in this hierarchy has an important role to play in the resolution process of a Domain Name:

  • The Registries (Verisign managing .COM and .NET)
  • Registrars (GoDaddy and Namecheap)
  • Registrants (those register a Domain Name)
  • ISPs
  • Managed DNS Service Providers

We all are a part of this system and it becomes extremely important for us, as Registrants, to keep an eye on how these multiple components are functioning to ensure that we have a stable and well-functioning system.

In this article, we will focus on a very important concept in DNS known as “Additional Records,” or “Glue Records.”

Additional Records or Glue Records
In simplest of terms, Glue records are A records or IP Addresses that are assigned or mapped to a Domain Name or a sub-domain. Glue records become extremely important when the Nameservers for a domain name are the sub-domains of the domain name itself.

The Glue records can be seen under the “Additional Section” of a DNS Response.

Let’s take an example to understand how Glue Records work; assume you have a domain name called “yourdomain.com” for which you are using the following set of Nameservers:

ns1. yourdomain.com

ns2. yourdomain.com

In the DNS Resolution process, the authoritative nameservers for yourdomain.com are ns1.yourdomain.com and ns2.yourdomain.com. The DNS resolution for ns1.yourdomain.com would first require the resolution of yourdomain.com, which returns the authoritative nameservers as ns1 and ns2.yourdomain.

As you may have already noticed, this creates a circular dependency, or other words a Loop, and the resolution never succeeds.

Glue records help in breaking this dependency by providing the IP Addresses for ns1.yourdomain.com and ns2.yourdomain.com in the lookup process, this breaks the loop from getting created as we no longer need to resolve the nameservers for the IP Addresses – these addresses are already provided in the form of “Glue Records”.

image2

In the example above, we see that Glue records helped remove the circular dependency by providing the A Records for ns1.ctrls.in and ns2.ctrls.in which were returned as the Authoritative Nameservers for the domain: ctrls.in. If this was not the case, the DNS Lookup would have failed because of a circular dependency.

For Domain names, which do not use sub-domains of the same domain as Authoritative Nameservers, Glue records help in reducing the number of lookups by providing the IP Addresses for the authoritative Nameservers. Here is an example for Wikipedia.com.

image1

In this case, Wikipedia.org returned ns1.wikimedia.org, ns2.wikimedia.org and ns3.wikimedia.org as the authoritative nameservers for the domain. This would have required an additional level of DNS lookup for Wikimedia.org to get the A/AAAA record for the domain name initially queried for i.e. Wikipedia.org.

One of our customers, a leading CDN provider headquartered in China, reached out to us a while ago, complaining that the A records being returned for two of their Nameservers were incorrect (Old IPs).

When investigating this case, we observed that when doing a DNS Experience test for the Nameservers, the IPs being returned by the authoritative nameservers were correct. However, when running a DNS Direct test to the Nameservers of the Domain using any of the gTLDs (a-m.gtld-servers.net.), the IPs returned were the incorrect IPs.

Digs to the domain name using the command: dig “domain name here” @a.root-servers.net returned the same response as Catchpoint’s DNS tests.

Further investigation led us to believe that this was one of those cases where the changes to the GLUE/Additional record at the Domain Registrar’s end was not pushed to the gTLD Servers.

Catchpoint DNS Monitors
Experience DNS Test For DNS tests that use the experience monitor, Catchpoint randomly selects a server from each level of the DNS route and queries it for the domain.
Direct DNS Test This test provides the complete query and response from the DNS server specified for the test along with the length of time it took to complete the test and any errors received during testing.


What fixed this issue?
Based on our recommendations, our Client reached out to the Domain Registrar for the domain and got the Glue records updated for the Domain. The change made was pushed to all the gTLD servers and the issue was resolved.

This incident emphasizes the importance of monitoring each level as well as each component of this amazingly vast system we know as DNS. Having a Monitoring strategy focused around DNS is not just recommended but is crucial to discover issues that may be under our control or out of our control.

The post Glue Records and Why They are Crucial appeared first on Catchpoint's Blog.

Read the original blog entry...

More Stories By Mehdi Daoudi

Catchpoint radically transforms the way businesses manage, monitor, and test the performance of online applications. Truly understand and improve user experience with clear visibility into complex, distributed online systems.

Founded in 2008 by four DoubleClick / Google executives with a passion for speed, reliability and overall better online experiences, Catchpoint has now become the most innovative provider of web performance testing and monitoring solutions. We are a team with expertise in designing, building, operating, scaling and monitoring highly transactional Internet services used by thousands of companies and impacting the experience of millions of users. Catchpoint is funded by top-tier venture capital firm, Battery Ventures, which has invested in category leaders such as Akamai, Omniture (Adobe Systems), Optimizely, Tealium, BazaarVoice, Marketo and many more.

@ThingsExpo Stories
The age of Digital Disruption is evolving into the next era – Digital Cohesion, an age in which applications securely self-assemble and deliver predictive services that continuously adapt to user behavior. Information from devices, sensors and applications around us will drive services seamlessly across mobile and fixed devices/infrastructure. This evolution is happening now in software defined services and secure networking. Four key drivers – Performance, Economics, Interoperability and Trust ...
With billions of sensors deployed worldwide, the amount of machine-generated data will soon exceed what our networks can handle. But consumers and businesses will expect seamless experiences and real-time responsiveness. What does this mean for IoT devices and the infrastructure that supports them? More of the data will need to be handled at - or closer to - the devices themselves.
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...
Multiple data types are pouring into IoT deployments. Data is coming in small packages as well as enormous files and data streams of many sizes. Widespread use of mobile devices adds to the total. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists will look at the tools and environments that are being put to use in IoT deployments, as well as the team skills a modern enterprise IT shop needs to keep things running, get a handle on all this data, and deli...
In his keynote at @ThingsExpo, Chris Matthieu, Director of IoT Engineering at Citrix and co-founder and CTO of Octoblu, focused on building an IoT platform and company. He provided a behind-the-scenes look at Octoblu’s platform, business, and pivots along the way (including the Citrix acquisition of Octoblu).
The Internet of Things is clearly many things: data collection and analytics, wearables, Smart Grids and Smart Cities, the Industrial Internet, and more. Cool platforms like Arduino, Raspberry Pi, Intel's Galileo and Edison, and a diverse world of sensors are making the IoT a great toy box for developers in all these areas. In this Power Panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, panelists discussed what things are the most important, which will have the most profound e...
Grape Up is a software company, specialized in cloud native application development and professional services related to Cloud Foundry PaaS. With five expert teams that operate in various sectors of the market across the USA and Europe, we work with a variety of customers from emerging startups to Fortune 1000 companies.
SYS-CON Events announced today that Grape Up 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. Grape Up is a software company specializing in cloud native application development and professional services related to Cloud Foundry PaaS. With five expert teams that operate in various sectors of the market across the U.S. and Europe, Grape Up works with a variety of customers from emergi...
Financial Technology has become a topic of intense interest throughout the cloud developer and enterprise IT communities. Accordingly, attendees at the upcoming 20th Cloud Expo at the Javits Center in New York, June 6-8, 2017, will find fresh new content in a new track called FinTech.
@ThingsExpo has been named the Most Influential ‘Smart Cities - IIoT' Account and @BigDataExpo has been named fourteenth by Right Relevance (RR), which provides curated information and intelligence on approximately 50,000 topics. In addition, Right Relevance provides an Insights offering that combines the above Topics and Influencers information with real time conversations to provide actionable intelligence with visualizations to enable decision making. The Insights service is applicable to eve...
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 20th Cloud Expo, which will take place on June 6-8, 2017 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 add...
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.
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, 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 strategy.
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
Today we can collect lots and lots of performance data. We build beautiful dashboards and even have fancy query languages to access and transform the data. Still performance data is a secret language only a couple of people understand. The more business becomes digital the more stakeholders are interested in this data including how it relates to business. Some of these people have never used a monitoring tool before. They have a question on their mind like “How is my application doing” but no id...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, June 6-8, 2017, at the Javits Center in New York City, NY and October 31 - November 2, 2017, Santa Clara Convention Center, CA. Learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
@GonzalezCarmen has been ranked the Number One Influencer and @ThingsExpo has been named the Number One Brand in the “M2M 2016: Top 100 Influencers and Brands” by Analytic. Onalytica analyzed tweets over the last 6 months mentioning the keywords M2M OR “Machine to Machine.” They then identified the top 100 most influential brands and individuals leading the discussion on Twitter.
Five years ago development was seen as a dead-end career, now it’s anything but – with an explosion in mobile and IoT initiatives increasing the demand for skilled engineers. But apart from having a ready supply of great coders, what constitutes true ‘DevOps Royalty’? It’ll be the ability to craft resilient architectures, supportability, security everywhere across the software lifecycle. In his keynote at @DevOpsSummit at 20th Cloud Expo, Jeffrey Scheaffer, GM and SVP, Continuous Delivery Busine...
Most technology leaders, contemporary and from the hardware era, are reshaping their businesses to do software in the hope of capturing value in IoT. Although IoT is relatively new in the market, it has already gone through many promotional terms such as IoE, IoX, SDX, Edge/Fog, Mist Compute, etc. Ultimately, irrespective of the name, it is about deriving value from independent software assets participating in an ecosystem as one comprehensive solution.
SYS-CON Events announced today that T-Mobile 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. As America's Un-carrier, T-Mobile US, Inc., is redefining the way consumers and businesses buy wireless services through leading product and service innovation. The Company's advanced nationwide 4G LTE network delivers outstanding wireless experiences to 67.4 million customers who are unwilling to compromise on ...