Happy New Year, fellow people trying to make things work.
Hopefully everyone is mostly succeeding despite the fact the war on entropy cannot be won.
Interesting problem this morning, in a quest to live a more portable life I just moved all my services from a home network to Amazon Web Services. Great deal on the Free Tier there, perfect thing to evict all your local services and get them in the cloud.
Problem is, I did the normal thing you'd expect to work after bringing up the Amazon instances - a simple 'yum update'.
yum did it's thing, packages were updated, and things looked just fine. You can't be sure your changes are good until you reboot though, and here's where the trouble started.
After a yum update on the stock RHEL 6 AMI, your AWS instance will fail to boot. You go to grab the system log from the instance and you see this most unhappy nugget at the bottom:
VFS: Cannot open root device "LABEL=_/" or unknown-block(0,0)