Click here to close now.

Welcome!

Microservices Expo Authors: Hovhannes Avoyan, Elizabeth White, Liz McMillan, Lori MacVittie, Pat Romanski

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

@MicroservicesExpo Stories
Python is really a language which has swept the scene in recent years in terms of popularity, elegance, and functionality. Research shows that 8 out 10 computer science departments in the U.S. now teach their introductory courses with Python, surpassing Java. Top-ranked CS departments at MIT and UC Berkeley have switched their introductory courses to Python. And the top three MOOC providers (edX, Coursera, and Udacity) all offer introductory programming courses in Python. Not to mention, Python ...
Most companies hope for rapid growth so it's important to invest in scalable core technologies that won't demand a complete overhaul when a business goes through a growth spurt. Cloud technology enables previously difficult-to-scale solutions like phone, network infrastructure or billing systems to automatically scale based on demand. For example, with a virtual PBX service, a single-user cloud phone service can easily transition into an advanced VoIP system that supports hundreds of phones and ...

Let's just nip the conflation of these terms in the bud, shall we?

"MIcro" is big these days. Both microservices and microsegmentation are having and will continue to have an impact on data center architecture, but not necessarily for the same reasons. There's a growing trend in which folks - particularly those with a network background - conflate the two and use them to mean the same thing.

They are not.

One is about the application. The other, the network. T...

Containers Expo Blog covers the world of containers, as this lightweight alternative to virtual machines enables developers to work with identical dev environments and stacks. Containers Expo 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. Bookmark Containers Expo Blog ▸ Here Follow new article posts on Twitter at @ContainersExpo
Disruptive macro trends in technology are impacting and dramatically changing the "art of the possible" relative to supply chain management practices through the innovative use of IoT, cloud, machine learning and Big Data to enable connected ecosystems of engagement. Enterprise informatics can now move beyond point solutions that merely monitor the past and implement integrated enterprise fabrics that enable end-to-end supply chain visibility to improve customer service delivery and optimize sup...
SYS-CON Events announced today that MetraTech, now part of Ericsson, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Ericsson is the driving force behind the Networked Society- a world leader in communications infrastructure, software and services. Some 40% of the world’s mobile traffic runs through networks Ericsson has supplied, serving more than 2.5 billion subscribers.
The Internet of Things (IoT) promises to evolve the way the world does business; however, understanding how to apply it to your company can be a mystery. Most people struggle with understanding the potential business uses or tend to get caught up in the technology, resulting in solutions that fail to meet even minimum business goals. In his session at @ThingsExpo, Jesse Shiah, CEO / President / Co-Founder of AgilePoint Inc., showed what is needed to leverage the IoT to transform your business. ...
Grow your business with enterprise wearable apps using SAP Platforms and Google Glass. SAP and Google just launched the SAP and Google Glass Challenge, an opportunity for you to innovate and develop the best Enterprise Wearable App using SAP Platforms and Google Glass and gain valuable market exposure. In his session at @ThingsExpo, Brian McPhail, Senior Director of Business Development, ISVs & Digital Commerce at SAP, outlined the timeline of the SAP Google Glass Challenge and the opportunity...
What are the benefits of using an enterprise-grade orchestration platform? In their session at 15th Cloud Expo, Nate Gordon, Director of Technology at Appcore, and Kedar Poduri, Senior Director of Product Management at Citrix Systems, took a closer look at the architectural design factors needed to support diverse workloads and how to run these workloads efficiently as a service provider. They also discussed how to deploy private cloud environments in 15 minutes or less.
I read an insightful article this morning from Bernard Golden on DZone discussing the DevOps conundrum facing many enterprises today – is it better to build your own DevOps tools or go commercial? For Golden, the question arose from his observations at a number of DevOps Days events he has attended, where typically the audience is composed of startup professionals: “I have to say, though, that a typical feature of most presentations is a recitation of the various open source products and compo...
In the first four parts of this series I presented an introduction to microservices along with a handful of emerging microservices patterns, and a discussion of some of the downsides and challenges to using microservices. The most recent installment of this series looked at ten ways that PaaS facilitates microservices development and adoption. In this post I’ll cover some words of wisdom, advice intended for individuals, teams, and organizations considering a move to microservices. I've gleaned...
Many people recognize DevOps as an enormous benefit – faster application deployment, automated toolchains, support of more granular updates, better cooperation across groups. However, less appreciated is the journey enterprise IT groups need to make to achieve this outcome. The plain fact is that established IT processes reflect a very different set of goals: stability, infrequent change, hands-on administration, and alignment with ITIL. So how does an enterprise IT organization implement change...
Right off the bat, Newman advises that we should "think of microservices as a specific approach for SOA in the same way that XP or Scrum are specific approaches for Agile Software development". These analogies are very interesting because my expectation was that microservices is a pattern. So I might infer that microservices is a set of process techniques as opposed to an architectural approach. Yet in the book, Newman clearly includes some elements of concept model and architecture as well as p...
There’s a lot of discussion around managing outages in production via the likes of DevOps principles and the corresponding software development lifecycles that does enable higher quality output from development, however, one cannot lay all blame for “bugs” and failures at the feet of those responsible for coding and development. As developers incorporate features and benefits of these paradigm shift, there is a learning curve and a point of not-knowing-what-is-not-known. Sometimes, the only way ...
This is the final installment of the six-part series Microservices and PaaS. It seems like forever since I attended Adrian Cockroft's meetup focusing on microservices. It's actually only been a couple of months, but much has happened since then: countless articles, meetups, and conference sessions focusing on microservices have been delivered, many meetings and design efforts at companies moving towards a microservices-based approach have been endured, and five installments of this blog series ...
Over the years, a variety of methodologies have emerged in order to overcome the challenges related to project constraints. The successful use of each methodology seems highly context-dependent. However, communication seems to be the common denominator of the many challenges that project management methodologies intend to resolve. In this respect, Information and Communication Technologies (ICTs) can be viewed as powerful tools for managing projects. Few research papers have focused on the way...
As the world moves from DevOps to NoOps, application deployment to the cloud ought to become a lot simpler. However, applications have been architected with a much tighter coupling than it needs to be which makes deployment in different environments and migration between them harder. The microservices architecture, which is the basis of many new age distributed systems such as OpenStack, Netflix and so on is at the heart of CloudFoundry – a complete developer-oriented Platform as a Service (PaaS...
How can you compare one technology or tool to its competitors? Usually, there is no objective comparison available. So how do you know which is better? Eclipse or IntelliJ IDEA? Java EE or Spring? C# or Java? All you can usually find is a holy war and biased comparisons on vendor sites. But luckily, sometimes, you can find a fair comparison. How does this come to be? By having it co-authored by the stakeholders. The binary repository comparison matrix is one of those rare resources. It is edite...
SYS-CON Events announced today that O'Reilly Media has been named “Media Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York City, NY. O'Reilly Media spreads the knowledge of innovators through its books, online services, magazines, and conferences. Since 1978, O'Reilly Media has been a chronicler and catalyst of cutting-edge development, homing in on the technology trends that really matter and spurring their adoption...
The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential. The DevOps Summit at Cloud Expo – to be held June 3-5, 2015, at the Javits Center in New York City – will expand the DevOps community, enable a wide...