Welcome!

@DevOpsSummit Authors: Amit Gupta, Liz McMillan, Elizabeth White, Yeshim Deniz, Pat Romanski

Related Topics: @DevOpsSummit, Java IoT, Microservices Expo, Linux Containers, @CloudExpo, @BigDataExpo

@DevOpsSummit: Blog Post

Software Quality Metrics for Your Continuous Delivery Pipeline | Part 3

It is safe to say that insightful logging and performance are two opposite goals

Let me ask you a question: would you say that you have implemented logging correctly for your application? Correct in the sense that it will provide you with all the insights you require to keep your business going once your users are struck by errors? And in a way that does not adversely impact your application performance? Honestly, I bet you have not. Today I will explain why you should turn off logging completely in production because of its limitations:

  • Relies on Developers
  • Lacks Context
  • Impacts Performance

Intrigued? Bear with me and I will show you how you can still establish and maintain a healthy and useful logging strategy for your deployment pipeline, from development to production, guided by metrics.

What Logging Can Do for You
Developers, including myself, often write log messages because they are lazy. Why should I set a breakpoint and fire up a debugger if it is so much more convenient to dump something to my console via a simple println()? This simple yet effective mechanism also works on headless machines where no IDE is installed, such as staging or production environments:

System.out.println("Been here, done that.");

Careful coders would use a logger to prevent random debug messages from appearing in production logs and additionally use guard statements to prevent unnecessary parameter construction:

if (logger.isDebugEnabled()) {
logger.debug("Entry number: " + i + " is " + String.valueOf(entry[i]));
}

Anyways, the point about logging is that that traces of log messages allow developers to better understand what their program is doing in execution. Does my program take this branch or that branch? Which statements were executed before that exception was thrown? I have done this at least a million of times, and most likely so have you:

if (condition) {
logger.debug("7: yeah!")
} else {
logger.debug("8: DAMN!!!")
}

Test Automation Engineers, usually developers by trade, equally use logging to better understand how the code under test complies with their test scenarios:

class AgentSpec extends spock.lang.Specification {

def "Agent.compute()"() {
def agent = AgentPool.getAgent()

when:
def result = agent.compute(TestFixtures.getData())

then:
logger.debug("result: "  + result);
result == expected
}
}

Logging is, undoubtedly, a helpful tool during development and I would argue that developers should use it as freely as possible if it helps them to understand and troubleshoot their code.

In production, application logging is useful for tracking certain events, such as the occurrence of a particular exception, but it usually fails to deliver what it is so often mistakenly used for: as a mechanism for analyzing application failures in production. Why?

Because approaches to achieving this goal with logging are naturally brittle: their usefulness depends heavily on developers, messages are without context, and if not designed carefully, logging may severely slow down your application.

Secretly, what you are really hoping to get from your application logs, in the one or the other form, is something like this:

A logging strategy that delivers out-of-the-box using dynaTrace: user context, all relevant data in place, zero config

The Limits of Logging
Logging Relies on Developers
Let's face it: logging is, inherently, a developer-centric mechanism. The usefulness of your application logs stands and falls with your developers. A best practice for logging in production says: "don't log too much" (see Optimal Logging @ Google testing blog). This sounds sensible, but what does this actually mean? If we recall the basic motivation behind logging in production, we could equally rephrase this as "log just enough information you need to know about a failure that enables you to take adequate actions". So, what would it take your developers to provide such actionable insights? Developers would need to correctly anticipate where in the code errors would occur in production. They would also need to collect any relevant bits of information along an execution path that bear these insights and, last but not least, present them in a meaningful way so that others can understand, too. Developers are, no doubt, a critical factor to the practicality of your application logs.

Logging Lacks Context
Logging during development is so helpful because developers and testers usually examine smaller, co-located units of code that are executed in a single thread. It is fairly easy to maintain an overview under such simulated conditions, such as a test scenario:

13:49:59 INFO com.company.product.users.UserManager - Registered user ‘foo'.
13:49:59 INFO com.company.product.users.UserManager - User ‘foo' has logged in.
13:49:59 INFO com.company.product.users.UserManager - User ‘foo' has logged out.

But how can you reliably identify an entire failing user transaction in a real-life scenario, that is, in a heavily multi-threaded environment with multiple tiers that serve piles of distributed log files? I say, hardly at all. Sure, you can go mine for certain isolated events, but you cannot easily extract causal relationships from an incoherent, distributed set of log messages:

13:49:59 INFO com.company.product.users.UserManager - User ‘foo' has logged in.
13:49:59 INFO com.company.product.users.UserManager - User ‘bar' has logged in.
...
13:49:60 SEVERE org.hibernate.exception.JDBCConnectionException: could not execute query
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:99)
...

After all, the ability to identify such contexts is key to deciding why a particular user action failed.

Logging Impacts Performance
What is a thorough logging strategy worth if your users cannot use your application because it is terribly slow? In case you did not know, logging, especially during peak load times, may severely slow down your application. Let's have a quick look at some of the reasons:

Writing log messages from the application's memory to persistent storage, usually to the file system, demands substantial I/O (see Top Performance Mistakes when moving from Test to Production: Excessive Logging). Traditional logger implementations wrote files by issuing synchronous I/O requests, which put the calling thread into a wait state until the log message was fully written to disk.

In some cases, the logger itself may cause a decent bottle-neck: in the Log4j library (up to version 1.2), every single log activity results in a call to an internal template method Appender.doAppend() that is synchronized for thread-safety (see Multithreading issues - doAppend is synchronised?). The practical implication of this is that threads, which log to the same Appender, for example a FileAppender, must queue up with any other threads writing logs. Consequently, the application spends valuable time waiting in synchronization instead of doing whatever the app was actually designed to do. This will hurt performance, especially in heavily multi-thread environments like web application servers.

These performance effects can be vastly amplified when exception logging comes into play: exception data, such as error message, stack trace and any other piggy-backed exceptions ("initial cause exceptions") greatly increase the amount of data that needs to be logged. Additionally, once a system is in a faulty state, the same exceptions tend to appear over and over again, further hurting application performance. We had once monitored a 30% drawdown on CPU resources due to more than 180,000 exceptions being thrown in only 5 minutes on one of our application servers (see Performance Impact of Exceptions: Why Ops, Test and Dev need to care). If we had written these exceptions to the file system, they would have trashed I/O, filled up our disk space in no time and had considerably increased our response times.

Subsequently, it is safe to say that insightful logging and performance are two opposite goals: if you want the one, then you have to make a compromise on the other.

For more logging tips click here for the full article.

More Stories By Martin Etmajer

Leveraging his outstanding technical skills as a lead software engineer, Martin Etmajer has been a key contributor to a number of large-scale systems across a range of industries. He is as passionate about great software as he is about applying Lean Startup principles to the development of products that customers love.

Martin is a life-long learner who frequently speaks at international conferences and meet-ups. When not spending time with family, he enjoys swimming and Yoga. He holds a master's degree in Computer Engineering from the Vienna University of Technology, Austria, with a focus on dependable distributed real-time systems.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@DevOpsSummit Stories
SYS-CON Events announced today that Yuasa System will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Yuasa System is introducing a multi-purpose endurance testing system for flexible displays, OLED devices, flexible substrates, flat cables, and films in smartphones, wearables, automobiles, and healthcare.
DevOps is under attack because developers don’t want to mess with infrastructure. They will happily own their code into production, but want to use platforms instead of raw automation. That’s changing the landscape that we understand as DevOps with both architecture concepts (CloudNative) and process redefinition (SRE). Rob Hirschfeld’s recent work in Kubernetes operations has led to the conclusion that containers and related platforms have changed the way we should be thinking about DevOps and controlling infrastructure. The rise of Site Reliability Engineering (SRE) is part of that redefinition of operations vs development roles in organizations.
SYS-CON Events announced today that Dasher Technologies 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. Dasher Technologies, Inc. ® is a premier IT solution provider that delivers expert technical resources along with trusted account executives to architect and deliver complete IT solutions and services to help our clients execute their goals, plans and objectives. Since 1999, we've helped public, private and nonprofit organizations implement technology solutions that speed and simplify their operations. As one of the fastest growing IT solution providers in the country, we have gained a reputation for effortless implementations with relentless follow-through and enduring support.
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 engineers can navigate the Carrier Ecosystem for your IT team acting as an extension of your business, producing a hassle-free experience.
We all know that end users experience the Internet primarily with mobile devices. From an app development perspective, we know that successfully responding to the needs of mobile customers depends on rapid DevOps – failing fast, in short, until the right solution evolves in your customers' relationship to your business. Whether you’re decomposing an SOA monolith, or developing a new application cloud natively, it’s not a question of using microservices – not doing so will be a path to eventual business failure.
SYS-CON Events announced today that Taica will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. Taica manufacturers Alpha-GEL brand silicone components and materials, which maintain outstanding performance over a wide temperature range -40C to +200C. For more information, visit http://www.taica.co.jp/english/.
SYS-CON Events announced today that TidalScale, a leading provider of systems and services, 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. TidalScale has been involved in shaping the computing landscape. They've designed, developed and deployed some of the most important and successful systems and services in the history of the computing industry - internet, Ethernet, operating systems, programming languages and microprocessors. Their elite team has collectively earned dozens of patents, three film credits and grown record setting businesses. And collectively, they've shipped more than 2 billion licensed products. They are difference makers who have a reputation for delivering innovative products and accomplishing what many others don't believe is even possible. They are ...
SYS-CON Events announced today that MIRAI Inc. will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. MIRAI Inc. are IT consultants from the public sector whose mission is to solve social issues by technology and innovation and to create a meaningful future for people.
SYS-CON Events announced today that IBM has been named “Diamond Sponsor” of SYS-CON's 21st Cloud Expo, which will take place on October 31 through November 2nd 2017 at the Santa Clara Convention Center in Santa Clara, California.
SYS-CON Events announced today that TidalScale 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. TidalScale is the leading provider of Software-Defined Servers that bring flexibility to modern data centers by right-sizing servers on the fly to fit any data set or workload. TidalScale’s award-winning inverse hypervisor technology combines multiple commodity servers (including their associated CPUs, memory storage and network) into one or more large servers capable of handling the biggest Big Data problems and most unpredictable workloads.
Join IBM November 1 at 21st Cloud Expo at the Santa Clara Convention Center in Santa Clara, CA, and learn how IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Cognitive analysis impacts today’s systems with unparalleled ability that were previously available only to manned, back-end operations. Thanks to cloud processing, IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Imagine a robot vacuum that becomes your personal assistant that knows everything and can respond to your emotions and verbal commands!
Infoblox delivers Actionable Network Intelligence to enterprise, government, and service provider customers around the world. They are the industry leader in DNS, DHCP, and IP address management, the category known as DDI. We empower thousands of organizations to control and secure their networks from the core-enabling them to increase efficiency and visibility, improve customer service, and meet compliance requirements.
In his session at 21st Cloud Expo, Michael Burley, a Senior Business Development Executive in IT Services at NetApp, will describe how NetApp designed a three-year program of work to migrate 25PB of a major telco's enterprise data to a new STaaS platform, and then secured a long-term contract to manage and operate the platform. This significant program blended the best of NetApp’s solutions and services capabilities to enable this telco’s successful adoption of private cloud storage and launching of virtual storage services to its enterprise market.
DevOps is often described as a combination of technology and culture. Without both, DevOps isn't complete. However, applying the culture to outdated technology is a recipe for disaster; as response times grow and connections between teams are delayed by technology, the culture will die. A Nutanix Enterprise Cloud has many benefits that provide the needed base for a true DevOps paradigm. In their Day 3 Keynote at 20th Cloud Expo, Chris Brown, a Solutions Marketing Manager at Nutanix, and Mark Lavi, a Nutanix DevOps Solution Architect, explored the ways that Nutanix technologies empower teams to react faster than ever before and connect teams in ways that were either too complex or simply impossible with traditional infrastructures.
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend 21st Cloud Expo October 31 - November 2, 2017, at the Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, and learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
Cloud Expo, Inc. has announced today that Andi Mann and Aruna Ravichandran have been named Co-Chairs of @DevOpsSummit at Cloud Expo Silicon Valley which will take place Oct. 31-Nov. 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. "DevOps is at the intersection of technology and business-optimizing tools, organizations and processes to bring measurable improvements in productivity and profitability," said Aruna Ravichandran, vice president, DevOps product and solutions marketing, CA Technologies. "It's this results-driven combination of technology and business that makes me so passionate about DevOps and its future in the industry. I am truly honored to take on this co-chair role, and look forward to working with the DevOps Summit team at Cloud Expo and attendees to advance DevOps."
SYS-CON Events announced today that mruby Forum will exhibit at the Japan External Trade Organization (JETRO) Pavilion 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. mruby is the lightweight implementation of the Ruby language. We introduce mruby and the mruby IoT framework that enhances development productivity. For more information, visit http://forum.mruby.org/.
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 real-time decisions based on a combination of real user monitoring, synthetic testing, APM, NGINX / local load balancers, and other data sources, is critical.
Digital transformation is changing the face of business. The IDC predicts that enterprises will commit to a massive new scale of digital transformation, to stake out leadership positions in the "digital transformation economy." Accordingly, attendees at the upcoming Cloud Expo | @ThingsExpo at the Santa Clara Convention Center in Santa Clara, CA, Oct 31-Nov 2, will find fresh new content in a new track called Enterprise Cloud & Digital Transformation.
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, will discuss how given the magnitude of today's application ecosystem, tweaking existing software to stitch various components together leads to sub-optimal solutions. This definitely deserves a re-think, and paves the way for a new breed of lightweight application servers that are micro-services and DevOps ready!
SYS-CON Events announced today that NetApp 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. NetApp is the data authority for hybrid cloud. NetApp provides a full range of hybrid cloud data services that simplify management of applications and data across cloud and on-premises environments to accelerate digital transformation. Together with their partners, NetApp empowers global organizations to unleash the full potential of their data to expand customer touchpoints, foster greater innovation and optimize their operations.
In a recent survey, Sumo Logic surveyed 1,500 customers who employ cloud services such as Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP). According to the survey, a quarter of the respondents have already deployed Docker containers and nearly as many (23 percent) are employing the AWS Lambda serverless computing framework. It’s clear: serverless is here to stay. The adoption does come with some needed changes, within both application development and operations. That means serverless is also changing the way we leverage public clouds. Truth-be-told, many enterprise IT shops were so happy to get out of the management of physical servers within a data center that many limitations of the existing public IaaS clouds were forgiven. However, now that we’ve lived a few years with public IaaS clouds, developers and CloudOps pros are giving a huge thumbs down to the ...
Enterprises are adopting Kubernetes to accelerate the development and the delivery of cloud-native applications. However, sharing a Kubernetes cluster between members of the same team can be challenging. And, sharing clusters across multiple teams is even harder. Kubernetes offers several constructs to help implement segmentation and isolation. However, these primitives can be complex to understand and apply. As a result, it’s becoming common for enterprises to end up with several clusters. This leads to a waste of cloud resources and increased operational overhead.
SYS-CON Events announced today that Avere Systems, a leading provider of enterprise storage for the hybrid cloud, 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. Avere delivers a more modern architectural approach to storage that doesn't require the overprovisioning of storage capacity to achieve performance, overspending on expensive storage media for inactive data or the overbuilding of data centers to house increasing amounts of storage infrastructure.
Containers are rapidly finding their way into enterprise data centers, but change is difficult. How do enterprises transform their architecture with technologies like containers without losing the reliable components of their current solutions? In his session at @DevOpsSummit at 21st Cloud Expo, Tony Campbell, Director, Educational Services at CoreOS, will explore the challenges organizations are facing today as they move to containers and go over how Kubernetes applications can deploy with legacy components, and also go over automated capabilities provided by operators to auto-update Kubernetes with zero downtime for current and secure deployments.