What is the underlying storage system for the VM? Ceph? ISCSI? Local Storage?
It looks like there could have been a storage/network blip and the OS FS might have been set RO. You should be able to run an fsck during the boot and see if that removes the RO flag.
Openstack - File system changing to read-only mode after 1 or 2 days of creating the instance. Not able to access any files after that. I am using Ubuntu 18.04 instances. I have installed openstack on my server which is also ubuntu 18.04. I have enough disk space. After this issues, when i try to remount , i am not able to do. what is the cause of this kind of issue and how to resolve this. Kindly help me in resolving this. Attaching logs here.