Can't login to Web interface

I had exactly the same symptoms in that the WebUI just redirected back to itself on successful login. I had done the usual triage:

  • ran perfectly
  • validate.php was all green

I checked in /opt/librenms/logs/librenms.log I had this pointer to the issue:

production.ERROR: ErrorException: session_start(): open(/var/lib/php/session/sess_02f1ad1f86608ad8c6b1dad1a9f2510e, O_RDWR) failed: Permission denied (13) in /opt/librenms/app/Http/Controllers/AjaxController.php:17

After running the below command the issue went away:

chown -R nginx:nginx /var/lib/php/session

The baffling thing is that I have an EC2 user-data script that builds my LibreNMS instance (chef on the backlog) that hasn’t changed in weeks but yesterday it stopped working. I checked the commits on librenms github page and nothing that stood out as the culprit but I guess there must have been some creep in dependencies that caused this…

For info, my vitals:


Component Version
LibreNMS 1.41-65-g290e07c
DB Schema 256
PHP 7.2.7
MySQL 5.5.56-MariaDB
RRDTool 1.4.8


[OK] Composer Version: 1.6.5
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database schema correct