Welcome!

@DevOpsSummit Authors: Pat Romanski, Liz McMillan, Zakia Bouachraoui, Elizabeth White, Yeshim Deniz

Related Topics: @DevOpsSummit, Java IoT, Microservices Expo, Linux Containers, Machine Learning , Agile Computing

@DevOpsSummit: Blog Post

Don’t Trust Your Log Files | @DevOpsSummit [#DevOps]

Most exceptions are handled by your code or by the frameworks your app uses

Don’t Trust Your Log Files: How and Why to Monitor All Exceptions

I would say that only one out of a million exceptions thrown in an application actually makes it to a log file - unless you run your application in verbose logging mode - Do you agree? No? Here is why I think that is: because most exceptions are handled by your code or by the frameworks your app uses. Here is a chart from an enterprise application showing that there are about 4000x more custom application exception objects thrown than important log messages written:

4000 times more Exceptions than log messages: Can they be ignored? What's their impact?

Why worry about these exceptions that nobody cares to write to a log file? Two reasons:

  1. They are typically thrown for a good reason and therefore indicate a problem, e.g., configuration issues in frameworks or runtime problems
  2. Every Exception object is a potential performance problem because it means the JVM needs to allocate memory, get the stack trace and dispose the object soon after

Reason #1: Configuration Problems
The following shows a transaction where the method getImagePath makes a web service call to a back-end server using HttpClient. getImagePath uses an HTTP Endpoint URL. The Web Service however only supports HTTPS (SSL). The web service call therefore fails with an SSLException. getImagePath retries three times until it gives up and just returns a default value to the caller. No log entry written, no exception thrown to the caller, everything seems okay to the outside world even though we have a severe impact on an end user who is waiting longer than necessary for an image that he doesn't get to see:

Exceptions are highlighting configuration problems (wrong URL) but the calling method is not doing anything with that information

Key Takeaways:

  • End Users: This code is executed for every user that executes this request and none of them will get the correct image path. Additionally, the user is waiting on it for several seconds. We all know what users will do if they have to wait too long.
  • Business: If your app delivers dynamic user-specific content, e.g., recommendations for that user, you need to ensure that no configuration problem causes your app to deliver incorrect content. As business owner you want to get alerted when a problem in the app causes incorrect responses to your users.
  • Operations: When users complain, there is no documented evidence of a problem (nothing in a log file). Make sure to monitor outgoing web requests and the status of these calls as this helps you to identify if you have requests that start failing or not delivering what they are supposed to deliver.
  • Developers: Everything probably worked well when they tested this web service in their own environment where they used a dummy or mocked web service endpoint. Make sure to add log for these situations and let Operations know how to configure these endpoints.

For Reason #2, and further insight, click here for the full article.

More Stories By Andreas Grabner

Andreas Grabner has been helping companies improve their application performance for 15+ years. He is a regular contributor within Web Performance and DevOps communities and a prolific speaker at user groups and conferences around the world. Reach him at @grabnerandi

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
Contino is a global technical consultancy that helps highly-regulated enterprises transform faster, modernizing their way of working through DevOps and cloud computing. They focus on building capability and assisting our clients to in-source strategic technology capability so they get to market quickly and build their own innovation engine.
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 benefits of the cloud without losing performance as containers become the new paradigm.
DevOpsSUMMIT at CloudEXPO will expand the DevOps community, enable a wide sharing of knowledge, and educate delegates and technology providers alike. Recent research has shown that DevOps dramatically reduces development time, the amount of enterprise IT professionals put out fires, and support time generally. Time spent on infrastructure development is significantly increased, and DevOps practitioners report more software releases and higher quality. Sponsors of DevOpsSUMMIT at CloudEXPO will benefit from unmatched branding, profile building and lead generation opportunities.
You want to start your DevOps journey but where do you begin? Do you say DevOps loudly 5 times while looking in the mirror and it suddenly appears? Do you hire someone? Do you upskill your existing team? Here are some tips to help support your DevOps transformation. Conor Delanbanque has been involved with building & scaling teams in the DevOps space globally. He is the Head of DevOps Practice at MThree Consulting, a global technology consultancy. Conor founded the Future of DevOps Thought Leaders Debate. He regularly supports and sponsors Meetup groups such as DevOpsNYC and DockerNYC.
In addition to 22 Keynotes and General Sessions, pick from 40 technical sessions in two tracks: (1) DevOpsSUMMIT (2) Cloud-Native & Serverless. EXPIRES AUGUST 31, 2018. Ticket prices: ($295-Aug 31) ($395-Oct 31) ($495-Nov 12) ($595-Walk-in) Does NOT include lunch. DevOps Institue Certification DevOps Institute Two-Day DevOps Certification Program EXPIRES AUGUST 31, 2018. Ticket prices: ($995-Aug 31) ($1,095-Oct 31) ($1,195-Nov 12) ($1,395-Walk-in)