[pve-devel] [PATCH v4 storage qemu-server container 0/9] move disk or volume to other guests

Aaron Lauterer a.lauterer at proxmox.com
Tue Nov 2 16:03:26 CET 2021

This is the continuation of 'disk-reassign' but instead of a separate
API endpoint we now follow the approach to make it part of the
'move-disk' and 'move-volume' endpoints for VMs and containers.

The main idea is to make it easy to move a disk/volume to another guest.
Currently this is a manual and error prone process that requires
knowledge of how PVE handles disks/volumes and the mapping which guest
they belong to.

With this, the 'qm move-disk' and 'pct move-volume' are changed in the
way that the storage parameter is optional as well as the new
target-vmid and target-{disk,volume}. This will keep old calls to move the
disk/volume to another storage working. To move to another guest, the
storage needs to be omitted.

Major changes since the last iteration as dedicated API endpoint [0] are
that the storage layer only implements the renaming itself. The layer
above (qemu-server and pve-container) define the name of the new
volume/disk.  Therefore it was necessary to expose the new
'find_free_volname' function.  The rename function on the storage layer
handles possible template references and the creation of the new volid
as that is highly dependent on the actual storage.

The following storage types are implemented at the moment:
* dir based ones
* (thin) LVM
* Ceph RBD

Most parts of the disk-reassign code has been taken and moved into the
'move_disk' and 'move_volume' endpoints with conditional checking if the
reassign code or the move to other storage code is meant to run
depending on the given parameters.

Changes since v3:
* added check if $vmid exists in $vmlist
* added check if volume if part of a snapshot (containers, qemu already
    had it)
* added section in storage/ApiChangeLog
* code style issues

Changes since v2:
* fixed base image handling
* fixed code style issues

Changes since v1 [2] (thx @ Fabian_E for the reviews!):
* drop exposed 'find_free_diskname' method
* drop 'wants_fmt_suffix' method (not needed anymore)
* introduce 'find_free_volname' which decides if only the diskname is
  needed or the longer path for directory based storages
* use $source_volname instead of $source_volid -> avoids some extra
  calls to get to $source_volname again
* make --target-{disk,volume} optional and fall back to source key
* smaller fixes in code quality and using existing functions like
  'parse_volname' instead of a custom regex (possible with the new

Changes since the RFC [1]:
* added check if target guest is replicated and fail if storage does not
  support replication
* only pass minimum of needed parameters to the storage layer and infer
  other needed information from that
* lock storage and check if the volume aready exists (handling a
  possible race condition between calling find_free_disk and the actual
* use a helper method to determine if the plugin needs the fmt suffix
  in the volume name
* getting format of the source and pass it to find_free_disk
* style fixes (long lines, multiline post-if, ...)

[0] https://lists.proxmox.com/pipermail/pve-devel/2021-April/047481.html
[1] https://lists.proxmox.com/pipermail/pve-devel/2021-June/048400.html
[2] https://lists.proxmox.com/pipermail/pve-devel/2021-July/049445.html

storage: Aaron Lauterer (2):
  storage: add new find_free_volname
  add disk rename feature

 ApiChangeLog                 | 10 ++++++++
 PVE/Storage.pm               | 29 +++++++++++++++++++++--
 PVE/Storage/LVMPlugin.pm     | 24 +++++++++++++++++++
 PVE/Storage/LvmThinPlugin.pm |  1 +
 PVE/Storage/Plugin.pm        | 45 ++++++++++++++++++++++++++++++++++++
 PVE/Storage/RBDPlugin.pm     | 26 +++++++++++++++++++++
 PVE/Storage/ZFSPoolPlugin.pm | 23 ++++++++++++++++++
 7 files changed, 156 insertions(+), 2 deletions(-)

qemu-server: Aaron Lauterer (4):
  cli: qm: change move_disk to move-disk
  Drive: add valid_drive_names_with_unused
  api: move-disk: add move to other VM
  api: move-disk: cleanup very long lines

 PVE/API2/Qemu.pm        | 234 ++++++++++++++++++++++++++++++++++++++--
 PVE/CLI/qm.pm           |   3 +-
 PVE/QemuServer/Drive.pm |   4 +
 3 files changed, 230 insertions(+), 11 deletions(-)

storage: Aaron Lauterer (3):
  cli: pct: change move_volume to move-volume
  api: move-volume: add move to another container
  api: move-volume: cleanup very long lines

 src/PVE/API2/LXC.pm | 286 +++++++++++++++++++++++++++++++++++++++-----
 src/PVE/CLI/pct.pm  |   3 +-
 2 files changed, 261 insertions(+), 28 deletions(-)


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