Welcome!

Blog Feed Post

Node.Js server monitoring, part 2

node-js-monitorLast time we mentioned two fundamental principles while monitoring any object:

1. The monitor should collect as much important information as possible that will allow to accurately evaluate the health state of an object.
2. The monitor should have little to no effect on the activity of the object.

Sure, these two principles work against each other in most of cases, but with Node.js they work together quite nicely because Node.js is based on event-driven technology and doesn’t use the traditional threads-driven approach. This technology allows to register many listeners for one event and process them in parallel almost independently. To avoid even a small effect on the production server, it was decided to separate the monitor into two parts – the first is the javascript module-plugin that listens to all server events and accumulates necessary information and the second is the Linux shell script that periodically runs the monitor-plugin by using the REST technique for collecting, processing, and sending information to the Monitis main server.

Normally, it is necessary to add couple lines in your existing Node.js server code to activate the monitor-plugin:

var monitor = require('monitor');// insert monitor module-plugin
....

var server = … // the definition of current Node.js server

….

monitor.Monitor(server); //add server to monitor

Now the monitor will begin collecting and measuring data. The monitor-plugin has an embedded simple HTTP server that sends accumulated data by request and should correspond (in current implementation) to the following pattern

http://127.0.0.1:10010/node_monitor?action=getdata&access_code=

where
10010 – the listen port of monitor-plugin (configurable)
‘node_monitor’ – the pathname keyword
‘action=getdata’ – command for getting collected data
‘access_code’ – the specially generated access code that changes for every session

Please notice that monitis-plugin server (in current implementation) listens the localhost only. This and usage of the security access code for every session gives enough security while monitoring. More detailed information can be found along with implemented code in the github repository.

Server monitoring metrics

There are a largely standard set of metrics which can be used to monitor the underlying health of any server.

* CPU Usage describes the level of utilisation of the system CPU(s) and is usually broken down into three states.
o IO Wait – indicates the proportion of CPU cycles spent waiting for IO (disk or network) events. If you experience large IO Wait proportions, it can indicate that your disks are causing a performance bottleneck.
o System – indicates the proportion of CPU cycles spent performing kernel-level processing. Generally you will find only a small proportion of your CPU cycles are spent on system tasks, Hence if you see spikes it could indicate a problem.
o User – indicates the proportion of CPU cycles spent performing user instigated processing. This is where you should see the bulk of your CPU cycles consumed; it includes activities such as web serving, application execution, and every other process not owned by the kernel.
o Idle – indicates the spare CPU capacity you have – all the cycles where the CPU is, quite literally, doing nothing.
* Load Average is a metric that indicates the level of load that a server is under at a given point in time. Usually evaluated as number of requests per second.
* RAM usage by server is broken down usually into the following parts.
o Free – the amount of unallocated RAM available. Linux systems tend to keep this as low as possible; and do not free up the system’s physical RAM until it is requested by another process.
o Inactive – RAM that is in-use for buffers and page caching, but hasn’t been used recently so will be reclaimed first for use by a running process.
o Active – RAM that has been used recently and will not be reclaimed unless we have insufficient Inactive RAM to claim from. In Linux systems this is generally the one to keep an eye on. Sudden, rapid increases signal a memory hungry process that will soon cause VM swapping to occur.
* The server uptime is a metric showing the elapsed time since the last reboot. Non-linear behavior of the server uptime line indicates that the server was rebooted somehow.
* Throughput – the amount of data traffic passing through the servers’ network interface is fundamentally important. It is usually broken down into inbound and outbound throughput and normally measured as average values for some period by kbit or kbyte per sec.
* Server Response time is defined as the duration from receiving a request to sending a response. Normally, it should not exceed reasonable timeout (usually this depends on the complexity of processing) but should be as little as possible. Usually, the average and peak response time is evaluated for some time period.
* The count of successfully processed requests is evaluated as the percentage of responses with 2xx status codes (success) to requests during observing time. This value should be as close as possible to 100%.

We have used part of these metrics and added some specific statistics that are important for our task (e.g. client platform, detailed info for response codes, etc.)

Test results

The results below were obtained on a Node.js server equipped with the monitor described above on a Debian6-x64. The server listens on HTTP (81) and HTTPS (443) ports and does not have a large load.


By double-clicking on a line you can view a specific part of the monitoring data.

The data can be shown in graphical view too.



In conclusion, the monitoring system has successfully tracked the metrics and found the Node.Js server to be in a good health state.

Share Now:del.icio.usDiggFacebookLinkedInBlinkListDZoneGoogle BookmarksRedditStumbleUponTwitterRSS

Read the original blog entry...

More Stories By Hovhannes Avoyan

Hovhannes Avoyan is the CEO of PicsArt, Inc.,

Latest Stories
Nordstrom is transforming the way that they do business and the cloud is the key to enabling speed and hyper personalized customer experiences. In his session at 21st Cloud Expo, Ken Schow, VP of Engineering at Nordstrom, discussed some of the key learnings and common pitfalls of large enterprises moving to the cloud. This includes strategies around choosing a cloud provider(s), architecture, and lessons learned. In addition, he covered some of the best practices for structured team migration an...
Digital transformation is about embracing digital technologies into a company's culture to better connect with its customers, automate processes, create better tools, enter new markets, etc. Such a transformation requires continuous orchestration across teams and an environment based on open collaboration and daily experiments. In his session at 21st Cloud Expo, Alex Casalboni, Technical (Cloud) Evangelist at Cloud Academy, explored and discussed the most urgent unsolved challenges to achieve f...
Recently, WebRTC has a lot of eyes from market. The use cases of WebRTC are expanding - video chat, online education, online health care etc. Not only for human-to-human communication, but also IoT use cases such as machine to human use cases can be seen recently. One of the typical use-case is remote camera monitoring. With WebRTC, people can have interoperability and flexibility for deploying monitoring service. However, the benefit of WebRTC for IoT is not only its convenience and interopera...
SYS-CON Events announced today that Synametrics Technologies will exhibit at SYS-CON's 22nd International Cloud Expo®, which will take place on June 5-7, 2018, at the Javits Center in New York, NY. Synametrics Technologies is a privately held company based in Plainsboro, New Jersey that has been providing solutions for the developer community since 1997. Based on the success of its initial product offerings such as WinSQL, Xeams, SynaMan and Syncrify, Synametrics continues to create and hone inn...
"WineSOFT is a software company making proxy server software, which is widely used in the telecommunication industry or the content delivery networks or e-commerce," explained Jonathan Ahn, COO of WineSOFT, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
The past few years have brought a sea change in the way applications are architected, developed, and consumed—increasing both the complexity of testing and the business impact of software failures. How can software testing professionals keep pace with modern application delivery, given the trends that impact both architectures (cloud, microservices, and APIs) and processes (DevOps, agile, and continuous delivery)? This is where continuous testing comes in. D
The dynamic nature of the cloud means that change is a constant when it comes to modern cloud-based infrastructure. Delivering modern applications to end users, therefore, is a constantly shifting challenge. Delivery automation helps IT Ops teams ensure that apps are providing an optimal end user experience over hybrid-cloud and multi-cloud environments, no matter what the current state of the infrastructure is. To employ a delivery automation strategy that reflects your business rules, making r...
There is a huge demand for responsive, real-time mobile and web experiences, but current architectural patterns do not easily accommodate applications that respond to events in real time. Common solutions using message queues or HTTP long-polling quickly lead to resiliency, scalability and development velocity challenges. In his session at 21st Cloud Expo, Ryland Degnan, a Senior Software Engineer on the Netflix Edge Platform team, will discuss how by leveraging a reactive stream-based protocol,...
Modern software design has fundamentally changed how we manage applications, causing many to turn to containers as the new virtual machine for resource management. As container adoption grows beyond stateless applications to stateful workloads, the need for persistent storage is foundational - something customers routinely cite as a top pain point. In his session at @DevOpsSummit at 21st Cloud Expo, Bill Borsari, Head of Systems Engineering at Datera, explored how organizations can reap the bene...
Most technology leaders, contemporary and from the hardware era, are reshaping their businesses to do software. They hope to capture value from emerging technologies such as IoT, SDN, and AI. Ultimately, irrespective of the vertical, it is about deriving value from independent software applications participating in an ecosystem as one comprehensive solution. In his session at @ThingsExpo, Kausik Sridhar, founder and CTO of Pulzze Systems, discussed how given the magnitude of today's application ...
Sanjeev Sharma Joins June 5-7, 2018 @DevOpsSummit at @Cloud Expo New York Faculty. Sanjeev Sharma is an internationally known DevOps and Cloud Transformation thought leader, technology executive, and author. Sanjeev's industry experience includes tenures as CTO, Technical Sales leader, and Cloud Architect leader. As an IBM Distinguished Engineer, Sanjeev is recognized at the highest levels of IBM's core of technical leaders.
Digital Transformation (DX) is not a "one-size-fits all" strategy. Each organization needs to develop its own unique, long-term DX plan. It must do so by realizing that we now live in a data-driven age, and that technologies such as Cloud Computing, Big Data, the IoT, Cognitive Computing, and Blockchain are only tools. In her general session at 21st Cloud Expo, Rebecca Wanta explained how the strategy must focus on DX and include a commitment from top management to create great IT jobs, monitor ...
The 22nd International Cloud Expo | 1st DXWorld Expo has announced that its Call for Papers is open. Cloud Expo | DXWorld Expo, to be held June 5-7, 2018, at the Javits Center in New York, NY, brings together Cloud Computing, Digital Transformation, Big Data, Internet of Things, DevOps, Machine Learning 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 busin...
"Digital transformation - what we knew about it in the past has been redefined. Automation is going to play such a huge role in that because the culture, the technology, and the business operations are being shifted now," stated Brian Boeggeman, VP of Alliances & Partnerships at Ayehu, in this SYS-CON.tv interview at 21st Cloud Expo, held Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA.
Continuous Delivery makes it possible to exploit findings of cognitive psychology and neuroscience to increase the productivity and happiness of our teams. In his session at 22nd Cloud Expo | DXWorld Expo, Daniel Jones, CTO of EngineerBetter, will answer: How can we improve willpower and decrease technical debt? Is the present bias real? How can we turn it to our advantage? Can you increase a team’s effective IQ? How do DevOps & Product Teams increase empathy, and what impact does empath...