This patch is adding a new cleaning step called "erase_devices_metadata"
to the GenericHardwareManager. This step is responsible for erasing the
metadata of the disks present in the node (partition tables, signatures,
filesystem identifiers etc...).
It's important to note that the "erase_devices" cleaning step will also
remove all these metadatas (because it will zero/shred the whole disk)
but, it takes a lot of time to run and for some usages of Ironic only
cleaning the device metadata and leaving the data from previous tenants
on the disk after the machine is recycled is fine. That's the use case
for systems using Ironic just to install the same base image onto many
nodes which will run another cloud on top afterwards (TripleO).
The new cleaning step has a default priority of 99, so it should run
before the "erase_devices" cleaning step so that we can guarantee that
the metadata was removed even in case of a failure when cleaning the
disks.
The version of the GenericHardwareManager was bumped to "1.1" with the
addition of this new clean step.
This patch make use of the "destroy_disk_metadata" method from ironic-lib
to get rid of the metadata.
Closes-Bug: #1603411
Change-Id: I3d7b39d5ee3e03ce63185e4168b1ac954a896c93
d528728090