NSX Load Balancer nginx process crashes when LB application drop rule is configured.

Products

• VMware NSX

Issue/Introduction

NSX native Load Balancer is configured, with LB application drop rule.
The Load Balancer nginx process crashed with the below entries encountered in var/log/syslog:

2025-07-10T00:02:53.005Z NSX 438763 - [nsx@6876 comp="nsx-edge" subcomp="node-mgmt" username="root" level="INFO"] Core dump generation received by process: 2511350 [nginx]
2025-07-10T00:02:53.007Z NSX 438763 - [nsx@6876 comp="nsx-edge" subcomp="node-mgmt" username="root" level="WARNING"] Core file generated: /var/log/core/core.nginx.#.gz

/var/dump:
total 186M
-rw-r--r--  1 root root 186M Jul 10 00:04 core.nginx.#.gz

 

Environment

VMware NSX 4.2.1.x

Cause

The cause of the issue is due to the LB application drop rule. When the http request hits the rule, the http request would enter the finalizing process, in which the memory request would be release, since the request is still been accessed to increase the LB drop rule stats it causes the core dump.

Resolution

This is a known issue impacting VMware NSX which will be fixed in future releases.

Workaround: 

Remove all the LB application drop rule as a workaround.

To remove the LB application drop rule, you may remove it from the UI:
Navigate to NSX UI -> Networking -> load balancing->virtual severs 

Find the virtual server "VIRTUAL_SERVER_443" and then get the load balancer rules. The drop rule is in the access phase.

Delete the "Connection Drop" rule