Debugging application crash issues by altering app log rate limit

Products

• VMware Tanzu Platform
• VMware Tanzu Application Service
• VMware Tanzu Application Service for VMs

Issue/Introduction

After a platform upgrade, customer observed a certain app crashing. The following log entries appeared:

2024-09-25T09:56:13.211-04:00 [APP/PROC/WEB/0]
[OUT] app instance exceeded log rate limit (16384 bytes/sec)

2024-09-25T09:56:14.307-04:00 [APP/PROC/WEB/0]
 [OUT] Exit status 137 (out of memory)

Environment

In order to execute the cf scale commands in this article, you need to have cf CLI v8 installed:

Installing the cf CLI

Resolution

Because the "exceeded log rate limit" error was unusual, customer asked to set the log limit to "unlimited." Many other apps already used this value, and customer asserted that this app formerly was set to "unlimited."

We changed the log rate limit using cf scale commands referenced in this doc (https://docs.vmware.com/en/VMware-Tanzu-Application-Service/6.0/tas-for-vms/quota-plans.html). This is the syntax:

cf scale -l LOG-RATE-LIMIT APP-NAME (using “-1”  for unlimited LOG-RATE-LIMIT)

With log rate limit set to unlimited, we were able to observe stack traces and errors that informed us why the log rate was so high.