Quote from Junipers facebook:
JUNOS TIP: Suppose you saw that your Alarm LED is red. Issue either the show
system alarm command or the show chassis alarm command.
One reason for chassis alarm is that the management port is not
connected. To clear this alarm, if you are not actually using the management
port, merely execute the following command: root@Junos#set
chassis alarm management-ethernet link-down ignore.
And one reason for the system alarm is that there is no rescue configuration
created. To fix this alarm, merely save a rescue configuration: root@
Junos#run request system configuration rescue save.
Let’s illustrate this:
root@Junos#run request system configuration rescue save