Weekly status #336

Weekly status for the week of 19th February to 24th February.


This past week has seen the arrival of two of our roadmap items; Dell Powerflex and UEFI variable editing support, as well as several improvements for VM functionality.


New Dell Powerflex storage driver

There are various enablement activities between Dell and Canonical as a part of our ongoing partnership. The latest of them is adding the ability for LXD to interface directly with its PowerFlex storage services in order to allow LXD instances and volumes to be stored on the platform.

Due to its design, PowerFlex will be another LXD storage driver offering remote storage capabilities similar to the already existing implementation for Ceph RBD.

The Powerflex driver also required modifications to the storage subsystem in LXD in order to accommodate the requirement of each volume having its own volatile.uuid property which is used by the Powerflex driver to generate a volume name in the Powerflex system. This allows LXD to overcome the volume length restrictions in Powerflex.

Documentation: Dell PowerFlex

Direct modification of VM UEFI variables (LXD snap only).

It is now possible to directly, and programmatically modify a VM’s UEFI variables using the new lxc config uefi command(s). This allows for customisation of the boot environment (such as customising the secure boot keys) without having to go into the VM’s UEFI firmware screen.

Documentation: UEFI variables for VMs

Device override when importing instance from backup file

It is now possible to use the --device flag when importing an instance from a backup file using lxc import. This allows for overriding the device config used when creating the instance, similar to the --device flag available on the lxc launch and lxc init commands.

VMs can be started with migration.stateful enabled and root disk’s size.state unset

Previously when using a VM with migration.stateful enabled (which allows for both stateful stop and live migration) the instance’s root disk would also need the size.state property to be set before the VM could be started. This check has now been deferred until the VM is attempted to be live migrated or statefully stopped. Additionally it is now possible to set the size.state property on a VM’s root disk whilst the VM is running.

API how-tos in the documentation

The documentation has been extended with an initial set of API how-tos to aid users when integrating with LXD’s API directly. These API examples are being added to each section of the documentation alongside the examples using the lxc CLI tool.

VM config volumes now ignore pool’s volume.block.filesystem setting

When using VMs atop of a storage pool that uses block backed volumes (such as LVM or Ceph RBD) the pool’s volume.block.filesystem setting is now ignored for new VMs, and the default filesystem (ext4) is always used.

This is because newer versions of xfs require the minimum volume size to be 300MiB, which was deemed wasteful for LXD’s VM config volume (especially on non-thinly provisioned pools), as it only requires less than 50MiBs. Additionally as the VM config volume is effectively an internal implementation detail and is not exposed to the VM or the end user directly using the specified filesystem, it was deemed acceptable for this to not be modifiable.

Bug fixes

  • Fixed an issue when rsync was being used for file transfer and the AppArmor profile being applied to it was prematurely removed, meaning that the transfer failed when used with the LXD snap. This is being backported into 5.0-stable branch and will be cherry-picked into the 5.0/stable snap channel.
  • Fixed regression with the authorization subsystem not expanding partial image fingerprints, nor taking into account effective projects when checking for access leading to overly restricted access in some cases.
  • Fixed an issue with a recent storage patch that incorrectly removed block.filesystem* settings for VM config drives on LVM and Ceph RBD. It should have only removed them from custom block volumes.

All changes

The items listed below is all of the work which happened over the past week and which will be included in the next release.


LXD Charm

  • Nothing to report this week

Distribution work

This section is used to track the work done in downstream Linux distributions to ship the latest LXD as well as work to get various software to work properly inside containers.


  • Nothing to report this week.


LXD snap