Welcome!

@ThingsExpo Authors: Elizabeth White, Nate Vickery, Yeshim Deniz, Pat Romanski, Liz McMillan

Related Topics: @ThingsExpo, Java IoT, Linux Containers, @CloudExpo, @DevOpsSummit

@ThingsExpo: Blog Feed Post

Top Node.js Metrics to Watch | @ThingsExpo #APM #IoT #Nodejs #BigData

A deep look at the top metrics in Node.js Applications to get a better understanding of why they are so important to monitor.

Top Node.js Metrics to Watch
by Stefan Thies

Monitoring Node.js Applications has special challenges. The dynamic nature of the language provides many “opportunities” for developers to produce memory leaks, and a single function blocking the event queue can have a huge impact on the overall application performance. Parallel execution of jobs is done using multiple worker processes using the “cluster” functionality to take full advantage of multi-core CPUs – but the master and worker processes belong to a single application, which means that they should be monitored together. Let’s have a deep look at the Top Metrics in Node.js Applications to get a better understanding of why they are so important to monitor.

Note: All images in this post are from Sematext’s SPM Performance Monitoring solution and its Node.js integration.

Garbage Collection & Process Memory – Node.js is based on Google’s Chrome V8 JavaScript engine. Garbage Collection reclaims memory used by objects that are not longer required. The V8 garbage collection stops the program execution. Incremental GC cycles (scavenging) process only a part of the Heap and are very fast. Full GC cycles deal with objects that survived multiple Incremental GC runs. Full GC runs are executed less frequently to minimize pauses in the program execution.

With regard to garbage collection metrics, we should first measure all the time spent for garbage collection. In addition, it is useful to see how often a full GC cycle — or incremental GC cycle — is executed. The size of heap memory can be compared with the size of the last GC run to see if there is a growing trend. That’s why the following metrics should be monitored:

  • Time consumed for garbage collection
  • Counters for full GC cycles
  • Counters for incremental GC cycles

Nodejs_garbage_collection

Garbage Collection Metrics

Aside from how often GC happens and how long it takes, we can measure the effect on memory by providing the following metrics:

  • Released memory between GC cycles (see above)
  • Process Heap Size and Heap Usage

Nodejs_process_memory

Process Memory Information

Event Loop – The secret of Node.js’s performance is its ability to be CPU bound and use async operations; in that way CPU can be highly utilized and doesn’t waste cycles waiting for I/O operations. This means a server can take many connections and will not be blocked for async operations. As soon as the operation is finished, callback functions are used to continue processing.   The implementation is based on a single event loop, which processes the async function calls in a separate thread. Using synchronous operations drags down performance because other operations need to wait to be executed.  That’s why the golden rule for Node.js performance is “don’t block the event loop”.

The metric to watch is the Latency to process the next event:

  • Slowest Event Handling (Max Latency)
  • Average Event Loop Latency
  • Fastest Event Handling (Min Latency)

Nodejs_slow_avg_fast

Slowest, average and fastest event processing

A high latency in the event loop might indicate the use of blocking (sync) or time-consuming functions in event handlers, which could impact the performance of the whole Node.js application.

Cluster Mode and number of processes – To scale Node.js beyond the capacity of a single process the use of master and worker processes is required – the so called “cluster” mode. Master processes share sockets with the forked worker process and can exchange messages with it. A typical use case for web servers is forking N worker processes, which operate on the shared server socket and handle the requests in round robin (since Node v0.12). In many cases programs choose N with the number of CPUs the server provides – that’s why a constant number of worker processes should be the regular case.  If this number changes it means worker processes have been terminated for some reason.  In the case of processing queues, workers might be started on demand.  In this scenario it would be normal that the number of workers changes all the time, but it might be interesting to see how long a higher number of workers was active. Using a tool like SPM for Node.js lets one track the number of workers. When picking a monitoring solution or developing your own monitoring for Node.js, make sure it is capable of filtering by hostname and worker ID.  Keep in mind Node.js workers can have a very short lifetime that traditional monitoring tools may not be able to handle well.

Nodejs_worker_count

Worker Count

For example, to compare event loop latency in different Node.js sub-processes, we need to be able to select workers we want to compare:

Nodejs_event_loop

Event Loop Latency for each Worker

Web Frameworks – There is a steadily growing number of frameworks to build web services using Node.js.  The most popular are: Express, Hapi.js, Restify, Mean.io, Meteor, and many more. When doing HTTP monitoring, here are some of the key metrics to pay attention to:

  • Response time (http/https)
  • Request rate
  • Error rates (total, error categories)
  • Request/Response content size

Nodejs_HTTP:HTTPS

HTTP/HTTPS Metrics Overview

Of course, Node.js apps don’t run in a vacuum.  They connect to other services, other types of applications, caches, data stores, etc.  As such, while knowing what key Node.js metrics are, monitoring Node.js alone or monitoring it separately from other parts of the infrastructure is not the best practice.  If there is one piece of advice I can give to anyone looking into (Node.js) monitoring it is this: when you buy a monitoring solution — or if you are building it for your own use — make sure you end up with a solution that is capable of showing you the big picture.  For example, Node.js is often used with Elasticsearch (see Top 10 Elasticsearch Metrics to Watch post), Redis, etc.  Seeing metrics for all the systems that surround Node.js apps is precious.  Here is just a small example of a dashboard showing a few Node.js and Elasticsearch metrics together.

Nodejs_combined_dashboard

Combined Dashboard of Node.js and Elasticsearch Metrics

So, those are our top Node.js metrics — what are YOUR top 10 metrics? We’d love to know so we can compare and contrast them with ours in a future post.  Please leave a comment, or send them to us via email or hit us on Twitter: @sematext.

And…if you’d like try SPM to monitor Node.js yourself, check out a Free 30-day trial by registering here.  There’s no commitment and no credit card required. Small startups, startups with no or very little outside funding, non-profit and educational institutions get special pricing – just get in touch with us.

[Note: this post originally appeared on Radar.com]

Filed under: Monitoring Tagged: Node.js, performance monitoring, spm

More Stories By Sematext Blog

Sematext is a globally distributed organization that builds innovative Cloud and On Premises solutions for performance monitoring, alerting and anomaly detection (SPM), log management and analytics (Logsene), and search analytics (SSA). We also provide Search and Big Data consulting services and offer 24/7 production support for Solr and Elasticsearch.

@ThingsExpo Stories
"We've been engaging with a lot of customers including Panasonic, we've been involved with Cisco and now we're working with the U.S. government - the Department of Homeland Security," explained Peter Jung, Chief Product Officer at Pulzze Systems, in this SYS-CON.tv interview at @ThingsExpo, held June 6-8, 2017, at the Javits Center in New York City, NY.
SYS-CON Events announced today that Calligo, an innovative cloud service provider offering mid-sized companies the highest levels of data privacy and security, 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. Calligo offers unparalleled application performance guarantees, commercial flexibility and a personalised support service from its globally located cloud plat...
"We are focused on SAP running in the clouds, to make this super easy because we believe in the tremendous value of those powerful worlds - SAP and the cloud," explained Frank Stienhans, CTO of Ocean9, Inc., in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
Internet of @ThingsExpo, taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, is co-located with 21st Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. The Internet of Things (IoT) is the most profound change in personal and enterprise IT since the creation of the Worldwide Web more than 20 years ago. All major researchers estimate there will be tens of billions devic...
"The Striim platform is a full end-to-end streaming integration and analytics platform that is middleware that covers a lot of different use cases," explained Steve Wilkes, Founder and CTO at Striim, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
"We provide IoT solutions. We provide the most compatible solutions for many applications. Our solutions are industry agnostic and also protocol agnostic," explained Richard Han, Head of Sales and Marketing and Engineering at Systena America, in this SYS-CON.tv interview at @ThingsExpo, held June 6-8, 2017, at the Javits Center in New York City, NY.
SYS-CON Events announced today that DXWorldExpo has been named “Global 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. Digital Transformation is the key issue driving the global enterprise IT business. Digital Transformation is most prominent among Global 2000 enterprises and government institutions.
SYS-CON Events announced today that Datera, that offers a radically new data management architecture, 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. Datera is transforming the traditional datacenter model through modern cloud simplicity. The technology industry is at another major inflection point. The rise of mobile, the Internet of Things, data storage and Big...
DX World EXPO, LLC., a Lighthouse Point, Florida-based startup trade show producer and the creator of "DXWorldEXPO® - Digital Transformation Conference & Expo" has announced its executive management team. The team is headed by Levent Selamoglu, who has been named CEO. "Now is the time for a truly global DX event, to bring together the leading minds from the technology world in a conversation about Digital Transformation," he said in making the announcement.
"MobiDev is a Ukraine-based software development company. We do mobile development, and we're specialists in that. But we do full stack software development for entrepreneurs, for emerging companies, and for enterprise ventures," explained Alan Winters, U.S. Head of Business Development at MobiDev, in this SYS-CON.tv interview at 20th Cloud Expo, held June 6-8, 2017, at the Javits Center in New York City, NY.
While the focus and objectives of IoT initiatives are many and diverse, they all share a few common attributes, and one of those is the network. Commonly, that network includes the Internet, over which there isn't any real control for performance and availability. Or is there? The current state of the art for Big Data analytics, as applied to network telemetry, offers new opportunities for improving and assuring operational integrity. In his session at @ThingsExpo, Jim Frey, Vice President of S...
SYS-CON Events announced today that DXWorldExpo has been named “Global 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. Digital Transformation is the key issue driving the global enterprise IT business. Digital Transformation is most prominent among Global 2000 enterprises and government institutions.
In his opening keynote at 20th Cloud Expo, Michael Maximilien, Research Scientist, Architect, and Engineer at IBM, discussed the full potential of the cloud and social data requires artificial intelligence. By mixing Cloud Foundry and the rich set of Watson services, IBM's Bluemix is the best cloud operating system for enterprises today, providing rapid development and deployment of applications that can take advantage of the rich catalog of Watson services to help drive insights from the vast t...
SYS-CON Events announced today that EnterpriseTech has been named “Media 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. EnterpriseTech is a professional resource for news and intelligence covering the migration of high-end technologies into the enterprise and business-IT industry, with a special focus on high-tech solutions in new product development, workload management, increased effic...
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 Cloud Academy named "Bronze Sponsor" of 21st International Cloud Expo which will take place October 31 - November 2, 2017 at the Santa Clara Convention Center in Santa Clara, CA. Cloud Academy is the industry’s most innovative, vendor-neutral cloud technology training platform. Cloud Academy provides continuous learning solutions for individuals and enterprise teams for Amazon Web Services, Microsoft Azure, Google Cloud Platform, and the most popular cloud com...
SYS-CON Events announced today that Cloudistics, an on-premises cloud computing company, 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. Cloudistics delivers a complete public cloud experience with composable on-premises infrastructures to medium and large enterprises. Its software-defined technology natively converges network, storage, compute, virtualization, and ...
SYS-CON Events announced today that CHEETAH Training & Innovation 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. CHEETAH Training & Innovation is a cloud consulting and IT training firm specializing in improving clients cloud strategies and infrastructures for medium to large companies.
SYS-CON Events announced today that Datanami has been named “Media 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. Datanami is a communication channel dedicated to providing insight, analysis and up-to-the-minute information about emerging trends and solutions in Big Data. The publication sheds light on all cutting-edge technologies including networking, storage and applications, and thei...
The current age of digital transformation means that IT organizations must adapt their toolset to cover all digital experiences, beyond just the end users’. Today’s businesses can no longer focus solely on the digital interactions they manage with employees or customers; they must now contend with non-traditional factors. Whether it's the power of brand to make or break a company, the need to monitor across all locations 24/7, or the ability to proactively resolve issues, companies must adapt to...