NSS requires the NDP user space module (ndpapp) to be loaded and running when NSS starts. If ndpapp is not running, modules in NSS that attempt eDirectory operations fail and prevent NSS from loading.
In some environments, when the NDP module (ndpmod) attempts to register the /dev/ndp device, the kernel routine misc_register() registers the device inside the kernel, but does not make it available in user space until about 17 seconds later. Because of the delay, the NDP user space module kills itself for about 10 seconds. NSS cannot start until ndpapp reloads itself. When these events occur, you see a message in the /var/log/messages file similar to the following that indicates the /dev/ndp is not available in user space:
Sep 1 19:37:54 servername ndpapp: stat: /dev/ndp: 2: No such file or directory
Increasing the UDEV event handling limits to 1024 has been tested and circumvents this problem. The /dev/ndp device gets created and is seen by ndpapp so that NSS can start.
Log in as the root user.
Open /etc/sysconfig/udev in a text editor, then locate the following lines:
Specify 1024 as the value for each parameter:
Save the file.
Reboot the server.