Skip to content

Contact sales

By filling out this form and clicking submit, you acknowledge our privacy policy.
  • Labs icon Lab
  • A Cloud Guru
Google Cloud Platform icon

Troubleshooting HAProxy Issues

Even well-designed and maintained HAProxy installations experience issues of all sorts; an HAProxy configuration issue, one or more servers down or misconfigured, content issues, application or site configuration issues — the possibilities are endless. HAProxy troubleshooting skills are key to maintaining a healthy and happy HAProxy environment. In this lab, we’re going to get hands-on with troubleshooting in an HAProxy environment. We have a number of issues to track down and fix in our HAProxy lab environment, and we will use a number of utilities and techniques that are available on a basic HAProxy installation to accomplish our goals. Upon completion of this lab, you will be able to track down and correct issues in an HAProxy environment.

Google Cloud Platform icon

Path Info

Clock icon Intermediate
Clock icon 45m
Clock icon Jun 30, 2021

Contact sales

By filling out this form and clicking submit, you acknowledge our privacy policy.

Table of Contents

  1. Challenge

    Troubleshoot HAProxy Service Issues

    HAProxy Troubleshooting Using systemctl.

    The first thing we might want to check is the status of our haproxy service itself. If it's not running, it's not working. Our haproxy service is managed by systemctl.

    Check the status of the haproxy service using systemctl. Ensure that the service is enabled and active. If it is not, fix it.

    HAProxy Troubleshooting Using journalctl.

    Both haproxy and systemd log to the systemd journal, so the next place we might want to check is there.

    Check the systemd journal using journalctl for HAProxy errors. Address any issues you might find that prevent HAProxy from starting.

  2. Challenge

    Troubleshoot HAProxy Configuration Issues

    Checking the HAProxy Configuration File.

    Sometimes we have one or more errors in our configuration file that prevent the haproxy service from starting. We can use the haproxy command to validate our configuration file.

    Validate the /etc/haproxy/haproxy.cfg file using the haproxy command. Address any issues you find that would prevent HAProxy from working properly.

  3. Challenge

    Troubleshooting HAProxy Issues Using the stats Interface

    Using the stats Socket for Troubleshooting.

    We might want to try using the stats socket directly to glean information about our environment. Let's give it a try! Add some formatting to the stats socket output using cut and column, and a looping mechanism using watch. Use CTRL-C to exit. Address any issues you find.

    Using the stats Web Interface for Troubleshooting.

    If we want an easy-to-read interface to HAProxy's stats facility, we can use the HAProxy stats web interface. Let's open a web browser and connect to port 8050 on the public IP of our HAProxy server. Address any issues you find.

  4. Challenge

    Troubleshoot HAProxy Using Log Information

    HAProxy Troubleshooting Using HAProxy Logs and halog.

    We can leverage the detailed and precise HAProxy logs for troubleshooting. When combined with the halog command, we can generate meaningful statistics that can help pinpoint issues.

    Try extracting some data from the /var/log/haproxy-combined-traffic.log file using halog:

    • Pull data on per-server HTTP statistics.
    • List URLs with 404 errors.
    • List URLs by the number of errors generated.
    • Try some of your own! See what evidence you can find!
    Examining HAProxy Logs Using grep.

    We can use our old friend grep to hand-examine our HAProxy logs. We can use grep to look for pattern matches in the log files.

    Try the following:

    • Look for elements with a DOWN status.
    • Find all the 404 error log entries.

The Cloud Content team comprises subject matter experts hyper focused on services offered by the leading cloud vendors (AWS, GCP, and Azure), as well as cloud-related technologies such as Linux and DevOps. The team is thrilled to share their knowledge to help you build modern tech solutions from the ground up, secure and optimize your environments, and so much more!

What's a lab?

Hands-on Labs are real environments created by industry experts to help you learn. These environments help you gain knowledge and experience, practice without compromising your system, test without risk, destroy without fear, and let you learn from your mistakes. Hands-on Labs: practice your skills before delivering in the real world.

Provided environment for hands-on practice

We will provide the credentials and environment necessary for you to practice right within your browser.

Guided walkthrough

Follow along with the author’s guided walkthrough and build something new in your provided environment!

Did you know?

On average, you retain 75% more of your learning if you get time for practice.

Start learning by doing today

View Plans