Welcome!

Containers Expo Blog Authors: Derek Weeks, Elizabeth White, Steve Latham, Gordon Haff, Liz McMillan

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

Microservices Expo: Blog Feed Post

Back to Basics: Health Monitors and Load Balancing

Because every connection counts

One of the truisms of architecting highly available systems is that you never, ever want to load balance a request to a system that is down. Therefore, some sort of health (status) monitoring is required. For applications, that means not just pinging the network interface or opening a TCP connection, it means querying the application and verifying that the response is valid.

This, obviously, requires the application to respond. And respond often. Best practices suggest determining availability every 5 seconds or so. That means every X seconds the load balancing service is going to open up a connection to the application and make a request. Just like a user would do.

That adds load to the application. It consumes network, transport, application and (possibly) database resources. Resources that cannot be used to service customers. While the impact on a single application may appear trivial, it's not. Remember, as load increases performance decreases. And no matter how trivial it may appear, health monitoring is adding load to what may be an already heavily loaded application.

evolution-of-health-monitoring

But Lori, you may be thinking, you expound on the importance of monitoring and visibility all the time! Are you saying we shouldn't be monitoring applications?

Nope, not at all. Visibility is paramount, providing the actionable data necessary to enable highly dynamic, automated operations such as elasticity. Visibility through health-monitoring is a critical means of ensuring availability at both the local and global level.

What we may need to do, however, is move from active to passive monitoring.

PASSIVE MONITORING

Passive monitoring, as the modifier suggests, is not an active process. The Load balancer does not open up connections nor query an application itself. Instead, it snoops on responses being returned to clients and from that infers the current status of the application.

For example, if a request for content results in an HTTP error message, the load balancer can determine whether or not the application is available and capable of processing subsequent requests. If the load balancer is a BIG-IP, it can mark the service as "down" and invoke an active monitor to probe the application status as well as retrying the request to another available instance – insuring end-users do not see an error. inband-monitoring

Passive (inband) monitors are not binary. That is, they aren't simple "on" or "off" based on HTTP status codes. Such monitors can be configured to track the number of failures and evaluate failure rates against a configurable failure interval. When such thresholds are exceeded, the application can then be marked as "down".

Passive monitors aren't restricted to availability status, either. They can also monitor for performance (response time). Failure to meet response time expectations results in a failure, and the application continues to be watched for subsequent failures.

Passive monitors are, like most inline/inband technologies, transparent. They quietly monitor traffic and act upon that traffic without adding overhead to the process.

Passive monitoring gives operations the visibility necessary to enable predictable performance and to meet or exceed user expectations with respect to uptime, without negatively impacting performance or capacity of the applications it is monitoring.

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
"ReadyTalk is an audio and web video conferencing provider. We've really come to embrace WebRTC as the platform for our future of technology," explained Dan Cunningham, CTO of ReadyTalk, in this SYS-CON.tv interview at WebRTC Summit at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
In 2014, Amazon announced a new form of compute called Lambda. We didn't know it at the time, but this represented a fundamental shift in what we expect from cloud computing. Now, all of the major cloud computing vendors want to take part in this disruptive technology. In his session at 20th Cloud Expo, John Jelinek IV, a web developer at Linux Academy, will discuss why major players like AWS, Microsoft Azure, IBM Bluemix, and Google Cloud Platform are all trying to sidestep VMs and containers...
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...
The many IoT deployments around the world are busy integrating smart devices and sensors into their enterprise IT infrastructures. Yet all of this technology – and there are an amazing number of choices – is of no use without the software to gather, communicate, and analyze the new data flows. Without software, there is no IT. In this power panel at @ThingsExpo, moderated by Conference Chair Roger Strukhoff, Dave McCarthy, Director of Products at Bsquare Corporation; Alan Williamson, Principal ...
WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
SYS-CON Media announced today that @WebRTCSummit Blog, the largest WebRTC resource in the world, has been launched. @WebRTCSummit Blog offers top articles, news stories, and blog posts from the world's well-known experts and guarantees better exposure for its authors than any other publication. @WebRTCSummit Blog can be bookmarked ▸ Here @WebRTCSummit conference site can be bookmarked ▸ Here
A critical component of any IoT project is what to do with all the data being generated. This data needs to be captured, processed, structured, and stored in a way to facilitate different kinds of queries. Traditional data warehouse and analytical systems are mature technologies that can be used to handle certain kinds of queries, but they are not always well suited to many problems, particularly when there is a need for real-time insights.
Providing secure, mobile access to sensitive data sets is a critical element in realizing the full potential of cloud computing. However, large data caches remain inaccessible to edge devices for reasons of security, size, format or limited viewing capabilities. Medical imaging, computer aided design and seismic interpretation are just a few examples of industries facing this challenge. Rather than fighting for incremental gains by pulling these datasets to edge devices, we need to embrace the i...
Web Real-Time Communication APIs have quickly revolutionized what browsers are capable of. In addition to video and audio streams, we can now bi-directionally send arbitrary data over WebRTC's PeerConnection Data Channels. With the advent of Progressive Web Apps and new hardware APIs such as WebBluetooh and WebUSB, we can finally enable users to stitch together the Internet of Things directly from their browsers while communicating privately and securely in a decentralized way.
Fifty billion connected devices and still no winning protocols standards. HTTP, WebSockets, MQTT, and CoAP seem to be leading in the IoT protocol race at the moment but many more protocols are getting introduced on a regular basis. Each protocol has its pros and cons depending on the nature of the communications. Does there really need to be only one protocol to rule them all? Of course not. In his session at @ThingsExpo, Chris Matthieu, co-founder and CTO of Octoblu, walked through how Octob...
The Internet of Things can drive efficiency for airlines and airports. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Sudip Majumder, senior director of development at Oracle, discussed the technical details of the connected airline baggage and related social media solutions. These IoT applications will enhance travelers' journey experience and drive efficiency for the airlines and the airports.
SYS-CON Events announced today that Catchpoint, a leading digital experience intelligence company, has been named “Silver Sponsor” of 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. Catchpoint Systems is a leading Digital Performance Analytics company that provides unparalleled insight into your customer-critical services to help you consistently deliver an amazing customer experience. Designed for digital business, C...
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...
In his General Session at 17th Cloud Expo, Bruce Swann, Senior Product Marketing Manager for Adobe Campaign, explored the key ingredients of cross-channel marketing in a digital world. Learn how the Adobe Marketing Cloud can help marketers embrace opportunities for personalized, relevant and real-time customer engagement across offline (direct mail, point of sale, call center) and digital (email, website, SMS, mobile apps, social networks, connected objects).
Things are changing so quickly in IoT that it would take a wizard to predict which ecosystem will gain the most traction. In order for IoT to reach its potential, smart devices must be able to work together. Today, there are a slew of interoperability standards being promoted by big names to make this happen: HomeKit, Brillo and Alljoyn. In his session at @ThingsExpo, Adam Justice, vice president and general manager of Grid Connect, will review what happens when smart devices don’t work togethe...
"There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...
The 20th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held June 6-8, 2017, at the Javits Center in New York City, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Containers, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal ...
"Tintri was started in 2008 with the express purpose of building a storage appliance that is ideal for virtualized environments. We support a lot of different hypervisor platforms from VMware to OpenStack to Hyper-V," explained Dan Florea, Director of Product Management at Tintri, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
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.
SYS-CON Events announced today that Super Micro Computer, Inc., a global leader in Embedded and IoT solutions, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 7-9, 2017, at the Javits Center in New York City, NY. Supermicro (NASDAQ: SMCI), the leading innovator in high-performance, high-efficiency server technology, is a premier provider of advanced server Building Block Solutions® for Data Center, Cloud Computing, Enterprise IT, Hadoop/Big Data, HPC and E...