Download rescure iso
wget https://download.grml.org/grml64-small_2022.11.iso

Create rescure system

openstack image create systemrescuecd \
  --file grml64-small_2022.11.iso \
  --disk-format iso \
  --container-format bare \
  --min-ram 512 \
  --property hw_cdrom_bus=scsi

# show image
openstack image list --name systemrescuecd

Attach rescure system

openstack server rescue --image systemrescuecd ${SERVER_ID}

# Login to VM console and fix issues
Detach rescure system

openstack server unrescue ${SERVER_ID}

Links
https://help.switch.ch/engines/documentation/rescue-vm/
https://grml.org/