Welcome!

IoT User Interface Authors: Elizabeth White, John Basso, Craig Lowell, Pat Romanski, XebiaLabs Blog

Related Topics: Microservices Expo, Containers Expo Blog, API Journal, IoT User Interface, @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.

@CloudExpo Stories
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform. In his session at @ThingsExpo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and shared the must-have mindsets for removing complexity from the develo...
In today's uber-connected, consumer-centric, cloud-enabled, insights-driven, multi-device, global world, the focus of solutions has shifted from the product that is sold to the person who is buying the product or service. Enterprises have rebranded their business around the consumers of their products. The buyer is the person and the focus is not on the offering. The person is connected through multiple devices, wearables, at home, on the road, and in multiple locations, sometimes simultaneously...
Basho Technologies has announced the latest release of Basho Riak TS, version 1.3. Riak TS is an enterprise-grade NoSQL database optimized for Internet of Things (IoT). The open source version enables developers to download the software for free and use it in production as well as make contributions to the code and develop applications around Riak TS. Enhancements to Riak TS make it quick, easy and cost-effective to spin up an instance to test new ideas and build IoT applications. In addition to...
Identity is in everything and customers are looking to their providers to ensure the security of their identities, transactions and data. With the increased reliance on cloud-based services, service providers must build security and trust into their offerings, adding value to customers and improving the user experience. Making identity, security and privacy easy for customers provides a unique advantage over the competition.
CenturyLink has announced that application server solutions from GENBAND are now available as part of CenturyLink’s Networx contracts. The General Services Administration (GSA)’s Networx program includes the largest telecommunications contract vehicles ever awarded by the federal government. CenturyLink recently secured an extension through spring 2020 of its offerings available to federal government agencies via GSA’s Networx Universal and Enterprise contracts. GENBAND’s EXPERiUS™ Application...
SYS-CON Events announced today that Isomorphic Software will exhibit at DevOps Summit at 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Isomorphic Software provides the SmartClient HTML5/AJAX platform, the most advanced technology for building rich, cutting-edge enterprise web applications for desktop and mobile. SmartClient combines the productivity and performance of traditional desktop software with the simp...
"We've discovered that after shows 80% if leads that people get, 80% of the conversations end up on the show floor, meaning people forget about it, people forget who they talk to, people forget that there are actual business opportunities to be had here so we try to help out and keep the conversations going," explained Jeff Mesnik, Founder and President of ContentMX, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
"When you think about the data center today, there's constant evolution, The evolution of the data center and the needs of the consumer of technology change, and they change constantly," stated Matt Kalmenson, VP of Sales, Service and Cloud Providers at Veeam Software, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Redis is not only the fastest database, but it is the most popular among the new wave of databases running in containers. Redis speeds up just about every data interaction between your users or operational systems. In his session at 19th Cloud Expo, Dave Nielsen, Developer Advocate, Redis Labs, will share the functions and data structures used to solve everyday use cases that are driving Redis' popularity.
Internet of @ThingsExpo, taking place November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with the 19th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world and ThingsExpo Silicon Valley Call for Papers is now open.
You think you know what’s in your data. But do you? Most organizations are now aware of the business intelligence represented by their data. Data science stands to take this to a level you never thought of – literally. The techniques of data science, when used with the capabilities of Big Data technologies, can make connections you had not yet imagined, helping you discover new insights and ask new questions of your data. In his session at @ThingsExpo, Sarbjit Sarkaria, data science team lead ...
"My role is working with customers, helping them go through this digital transformation. I spend a lot of time talking to banks, big industries, manufacturers working through how they are integrating and transforming their IT platforms and moving them forward," explained William Morrish, General Manager Product Sales at Interoute, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
To leverage Continuous Delivery, enterprises must consider impacts that span functional silos, as well as applications that touch older, slower moving components. Managing the many dependencies can cause slowdowns. See how to achieve continuous delivery in the enterprise.
Up until last year, enterprises that were looking into cloud services usually undertook a long-term pilot with one of the large cloud providers, running test and dev workloads in the cloud. With cloud’s transition to mainstream adoption in 2015, and with enterprises migrating more and more workloads into the cloud and in between public and private environments, the single-provider approach must be revisited. In his session at 18th Cloud Expo, Yoav Mor, multi-cloud solution evangelist at Cloudy...
Aspose.Total for .NET is the most complete package of all file format APIs for .NET as offered by Aspose. It empowers developers to create, edit, render, print and convert between a wide range of popular document formats within any .NET, C#, ASP.NET and VB.NET applications. Aspose compiles all .NET APIs on a daily basis to ensure that it contains the most up to date versions of each of Aspose .NET APIs. If a new .NET API or a new version of existing APIs is released during the subscription peri...
Security, data privacy, reliability, and regulatory compliance are critical factors when evaluating whether to move business applications from in-house, client-hosted environments to a cloud platform. Quality assurance plays a vital role in ensuring that the appropriate level of risk assessment, verification, and validation takes place to ensure business continuity during the migration to a new cloud platform.
SYS-CON Events announced today that 910Telecom will exhibit at the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Housed in the classic Denver Gas & Electric Building, 910 15th St., 910Telecom is a carrier-neutral telecom hotel located in the heart of Denver. Adjacent to CenturyLink, AT&T, and Denver Main, 910Telecom offers connectivity to all major carriers, Internet service providers, Internet backbones and ...
Ovum, a leading technology analyst firm, has published an in-depth report, Ovum Decision Matrix: Selecting a DevOps Release Management Solution, 2016–17. The report focuses on the automation aspects of DevOps, Release Management and compares solutions from the leading vendors.
Continuous testing helps bridge the gap between developing quickly and maintaining high quality products. But to implement continuous testing, CTOs must take a strategic approach to building a testing infrastructure and toolset that empowers their team to move fast. Download our guide to laying the groundwork for a scalable continuous testing strategy.
Adding public cloud resources to an existing application can be a daunting process. The tools that you currently use to manage the software and hardware outside the cloud aren’t always the best tools to efficiently grow into the cloud. All of the major configuration management tools have cloud orchestration plugins that can be leveraged, but there are also cloud-native tools that can dramatically improve the efficiency of managing your application lifecycle. In his session at 18th Cloud Expo, ...