A coworker brought this up, and it’s worth noting:
what's wrong with this? # parted -s /dev/sda mkpart primary ext2 1M 8M # mke2fs /dev/sda1 Unfortunately, this will occasionally fail with this error from mk2fs: The file /dev/sda1 does not exist and no size was specified.
This is due to a race condition in the udevd and mke2fs. Since /dev/sda has just been changed, udevd watches for a “close after open for writing” signal from inotify, and then does a BLKRRPART ioctl on /dev/sda. If mk2efs tries to write during this time, /dev/sda1 may briefly not exist.
But flock will prevent the BLKRRPART from being issued, so this will reliably create a partition:
flock -s /dev/sda -c "parted -s /dev/sda mkpart primary ext2 1M 8M && mke2fs /dev/sda1"