Config CONF.libvirt.inject_partition=-1, build instance with metadata will remain some images in /var/tmp/.guestfs-0/appliance.d

[jiangyuhao]

Description
===========
Boot instance with metadata will remain some images in '/var/tmp/.guestfs-0/appliance.d' when this compute_node config CONF.libvirt.inject_partition=-1.

Steps to reproduce
==================
1) Config inject_partition=-1(/etc/nova/nova.conf) in compute_node.
2) boot instance with metadata on this compute_node.
3) boot instance success but some images were remained.

Expected result
===============
In the end of booting instance, can remove those images in /var/tmp/.guestfs-0/appliance.d

Actual result
=============
Those images be left forever.

Environment
===========
1. Exact version of OpenStack you are running. See the following
  openstack-nova-api-18.0.2-1.el7.noarch

2. Which hypervisor did you use?
   Libvirt + KVM

2. Which storage type did you use?
   LVM

3. Which networking type did you use?
   Neutron with OpenVSwitch)

Logs & Configs
==============
{'message': u"No operating system found in <LocalFileImage:{'path': u'/var/lib/nova/instances/7e79433f-917d-43da-88f0-757c6d3572c5/disk', 'format': 'qcow2'}>", 'class': 'NovaException', 'kwargs': {'code': 500}}

[Matt Riedemann (mriedem)]

This sounds like more of a libguestfs issue than a nova issue, unless nova isn't creating the guest in such a way that libguestfs would cleanup properly.

What version of libguestfs are you using?

Also note that file injection as a feature is disabled by default (it has been for years) and is also deprecated in the API:

https://docs.openstack.org/nova/latest/reference/api-microversion-history.html#id52

So in all this is very low priority to resolve IMO.

[Matt Riedemann (mriedem)]

What happens with the files in /var/tmp/.guestfs-0/appliance.d after you restart the compute host operating system? They still are not removed even though they are in a tmp directory?

[Kashyap Chamarthy (kashyapc)]

So, the libguestfs files in /var/tmp/.guestfs-0/appliance.d are the *cache* and libguestfs never removes those files.

(Double-checked with libguestfs maintainers.)

And Nova _shouldn't_ delete those files either; that's wrong.

Instead, we suggest to use a tool like `systemd-tmpfiles`; from its man page:

"`systemd-tmpfiles` creates, deletes, and cleans up volatile and temporary files and directories, based on the configuration file format and location specified in tmpfiles.d(5)"

So we should close this bug as "invalid", afraid.