Solve the Linux operating system can not log in

Received feedback from the development that one of the test machines can not be logged in after restarting.

It is not possible to log in to the local SSH without logging in to the remote SSH, so restart the single-user mode and try to solve the problem.

1. Check the disk and everything works.

2, check the /etc/passwd file for no exceptions.

3, check the ssh configuration file is normal.

4, add a new user, restart still can not log in.

5, check /etc/proflie configuration is normal.

So I thought that development once wanted to set the maximum number of open files, so check

cat /etc/security/limits.conf

* soft nofile 6553500

* hard nofile 6553500

The maximum number of files opened for discovery settings is too large, commented out. Restart everything and log in normally.