diff options
Diffstat (limited to 'README')
| -rw-r--r-- | README | 55 |
1 files changed, 55 insertions, 0 deletions
@@ -0,0 +1,55 @@ +This source repository builds packages that work with initramfs-tools +to add function to an initramfs that is likely cloud specific. + +Most likely, you do not want to install these packages unless you know +what you're doing. + +== growroot == +This initramfs module will re-write the partition table of a disk +so that the root partition has as much space as possible, bumping it +up to the edge of the disk, or the edge of the next partition. + +This is valueable in an environment where a volume can be grown past +its original size. It addresses the following situation: + * The initial [virtual] disk has a partition table on it + * The provisioning system creates a volume with additional space + at the end of the disk (after the root partition) + * the system boots, but cannot use the additional space without a reboot + because the kernel will not re-read the partition table information + of a disk that is in use. + +The way this is addressed is: + * in the initramfs unmount the root filesystem + * rewrite the partition table + * tell the kernel to re-read + * remount the root filesystem + +== rescuevol == +When installed the initramfs will check to see if any partitions +with a label of 'RESCUE_VOL' are attached. If such a volume is attached, +it will boot off that volume rather than the root volume. + +This is useful in a cloud environment, when the user is able to attach +and detach volumes to a running system, but has no other mechanism +for interupting of fixing a failed boot. It is analogous to inserting +a rescue CD into a system to recover from failure. + +It may be helpful in the case where the kernel and ramdisk can be loaded +from the instance, but the system is unusable. This could occur if +an error left ssh access broken or the system didn't come all the way up. + +The user could attach a correctly labeled volume, reboot the instance +and access the system to fix it. + +If the volume contains a file '/etc/rescuevol-ignore' it will be ignored. +This allows you to fix your instance, create that volume and *not* boot the +rescue volume on next boot + +== overlayroot == +Configure overlayfs filesystems over the root device based on +configuration provided by kernel command line or in-image config. + +see overlayroot/etc/overlayroot.conf for more information. + +== dyn-netconf == +see dyn-netconf/doc/README.txt |