Troubleshooting

This guide explains how to determine, diagnose, and fix issues you might encounter when using NGINX Instance Manager.


Known Issues

View the known issues and possible workarounds in the NGINX Management Suite modules:


How To Look Up the Installed Version

  • To see which version of an NGINX Management Suite module is installed, run the following commands:

    • Look up the installed version of NGINX Instance Manager:

      yum info nms-instance-manager
      
    • Look up the installed version of NGINX Management Suite API Connectivity Manager:

      yum info nms-api-connectivity-manager
      

    • Look up the installed version of NGINX Instance Manager:

      dpkg -s nms-instance-manager
      
    • Look up the installed version of NGINX API Connectivity Manager:

      dpkg -s nms-api-connectivity-manager
      

Troubleshooting Instance Manager

Newly installed NGINX instances aren’t returned

Description

After installing NGINX and the NGINX Agent on an instance, the instance is not returned when calling GET https://hostname/api/platform/v1/systems.

Resolution

The NGINX service needs to be running before you start the NGINX Agent service.

To resolve the issue, try restarting the NGINX Agent service:

sudo systemctl restart nginx-agent

NGINX service fails to start after upgrading NGINX OSS on RHEL 8

Description

In some cases, after upgrading NGINX OSS on RHEL 8, the NGINX service fails to start and returns an error similar to the following:

Job for nginx.service failed because the control process exited with error code.

The error log may include entries similar to the following example:

022/05/12 16:11:23 [emerg] 69688#69688: still could not bind()
22022/05/12 16:18:34 [emerg] 70092#70092: bind() to 0.0.0.0:80 failed (98: Address already in use)

Resolution

Ensure there isn’t a process bound to port 80 or 443.

  1. To stop processes bound to ports 80 and 443, run the following commands:

    sudo fuser -k 80/tcp
    sudo fuser -k 443/tcp
    
  2. Restart the NGINX service:

    sudo service nginx restart
    

Scan reports NGINX versions as undefined when NGINX App Protect is enabled

Description

When scanning for NGINX instances, the NGINX version is reported as undefined when NGINX App protect is installed.

Resolution

This behavior is by design. As a security precaution when NGINX App Protect is installed, the NGINX server does not report its version in any HTTP headers. The NGINX Plus and Instances pages in the web interface will continue to report the NGINX and NGINX App Protect versions.