You will have to reboot the VM instance and once it is coming UP, please get into the ‘greb’ menu and follow the below steps:
Access the grub menu & edit it with ‘e’
The default grub protection username & password is root/abc123
Default grub menu options will be displayed after this as shown below ,
Remove the entries after “root=/dev/mapper/jmpvgnocf-lvroot” in kernel line with init=/bin/bash as shown below ,
Linux /vmlinuz-2.6.32-100.24.1.el5 root=/dev/mapper/jmpvgnocf-lvroot ro /
console =tty1 console=ttys0,9600n8 acpi_enforce_resources=lax
Linux /vmlinuz-2.6.32-100.24.1.el5 root=/dev/mapper/jmpvgnocf-lvroot init=/bin/bash
Boot in to the system with Ctrl-x or F10 & make the file system rw with “mount –o remount,rw /” command.
Finally change admin password with “passwd admin” command then exit & reboot the system.
Note: Grub mode protection is enabled with either “password” or “pbkdf” mode passwords in 13.x ,search for password in /boot/grub/grub.cfg file & replace the password with the one created with either “grub-mkpasswd-pbkdf2” or “grub-md5-crypt” for changing the default password.
** Many thanks to Lijo K. from Juniper support for sharing those information with me**
Abed AL-R. B.