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The following command can be run to find read-only file system in your instance.
grep "\sro[\s,]" /proc/mounts
Details
Reboot the instance through the OpenStack Horizon dashboard.
Browse to the Nebula dashboard at nebula.ncsa.illinois.edu.
In the drop-down "Actions" menu to the right of your instance select "
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Hard Reboot Instance". A soft reboot tries to shut down the instance gracefully and normally would be preferable to a hard reboot, which halts the instance immediately. However, in this case, the soft reboot will try shutting down services and writing to disk and at this point the disk is read-only.
Confirm the rebootinstance has rebooted.
Logging in as root
To log in as root you must previously have set a password for root in the instance.
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The fsck command can recover your disk partition but there is no guarantee that it will work correctly. The fsck operation can occasionally cause data corruption on active disks. For this reason, the fsck procedure should only be performed on unmounted or read-only file system systems to minimize this risk. Problems can still occur in cases of severe damage though, so consider these last-resort methods for data recovery.
Use the "mount" command to verify the file system you wish to fix is read-only.
/dev/vdb1 on /tmp/newdir type ext4 (ro,relatime,seclabel,data=ordered)
Run fsck on the file device you wish to check, for example "fsck ". You may be prompted.
fsck /dev/vdb1
Normally, the file system is consistent, and the fsck command merely reports on the number of files, used blocks, and free blocks in the file system. If the file system is inconsistent, the fsck command displays information about the inconsistencies found and prompts you for permission to repair them.". You may be prompted.
After fsck has been run it is important to check the /lost+found directory in the checked file system. This is where fsck puts partially recovered files. Sometimes, fsck is able to recover file data, but it cannot find a reference to the file on the filesystem.When this happens, fsck places the files in the /lost+found directory so that you can manually try to figure out what the file is. If there are files in this directory check to see if you can identify them. Often these are files that were previously deleted but were still being used when the system crashed. It is worth checking them though to be sure.
Contact "nebula@ncsa.illinois.edu" with any questions.