Navigate to the Nirin Dashboard at cloud.nci.org.au
Click on the Instance which does not boot.
Click on the Console tab and open the console in a separate browser window.
In the Console window click on the Send Ctrl-Alt-Del button
Wait for the Instance to reboot to the GRUB menu
Press 'e' when one of the GRUB boot option lines are selected
Scroll down to the Kernel Command Line
Remove the text console=ttyS0,115200 to ensure that the (novnc based) Console is able to accept IO from keyboard
Add a relevant option to drop down to a recovery terminal
If you want to drop down to your ramdisk image with no filesystems mounted, add rd.break to the kernel command line.
If you want a bash prompt with the rootfs mounted, add init=/bin/bash
Press Ctrl-x to boot with modified kernel command line
You should see a bash prompt after some initial boot steps. At this point if you need to make changes to any files on the rootfs, please remount it with the rw flag:
mount -o remount,rw /
Make the changes as required. For example, if you have an issue with a /g/data mount included in /etc/fstab, open /etc/fstab and comment the problematic line
Your Instance should now boot