The nova-lxd driver has to take a slightly different approach
to virtual interface wiring due to a lack of an equivalent to
'launch and pause' in LXD.
For some interface types, the last mile tap device needs to
be present for vif plugging to complete successfully which
occurs prior to the instance being launched; This change
refactors the vif module to create veth pairs directly
in nova-lxd, rather than delegating this to LXD as part of
a bridged network interface type. This allows vif plugging
to complete prior to the instance being created in LXD.
The side effect of this change is that all currently supported
interface types are now configured as 'physical' interfaces
in LXD profiles for instances - wiring to bridges is handled
directly by the nova-lxd driver instead.
This change has been validated with:
ovs driver + iptables hybrid firewall driver
ovs driver + openvswitch native firewall driver
linuxbridge driver + iptables hybrid firewall driver
The VIF wiring approach is described in detail in the VIF
wiring documentation included in this change.
Previously, the nova-lxd driver was installed to nova_lxd.
Currently, nova-lxd driver installs into nova.
This commit updates the documentation to reflact that