This first method will automatically log out idle users who are logged on either at the local console or remotely via SSH. Go into the /etc/profile.d/ directory and create the autologout.sh file with the following contents:

TMOUT=100
readonly TMOUT
export TMOUT

This sets a timeout value of 100 seconds. (TMOUT is a Linux environmental variable that sets timeout values.)

Set the executable permission for everybody:

sudo chmod +x autologout.sh

Log out and then log back in. Then, let the VM sit idle. After 100 seconds, you should see that the VM is back at the login prompt. Note, though, that if any users are already logged in at the time you create this file, the new configuration won't take effect for them until they log out and then log back in.