To void this message on pre Vagrant 1.8
```bash
There are errors in the configuration of this machine. Please fix
the following errors and try again:
VirtualBox Provider:
* The following settings shouldn't exist: linked_clone
```
In cd93721, I relied on a suprising combination of quotes to protect ssh
execution to strip the quoted path to the private key file.
Since any ssh command line argument can be passed via
`ANSIBLE_SSH_ARGS`, it is quite more readable and easy to rely on the
`-i` argument, which is not affected like `-o IdentityFile=...` and also
supports multiple occurences.
See also http://sourceforge.net/p/fuse/mailman/message/30498048/
Finally fix#6671
Note that I decided to not squash both commits for better
documentation and traceability.
Surprisingly (to me at least), a simple quote enclosure was not enough
to fix the problem.
Caveat: the stringified ansible-playbook command logged in verbose mode
is wrongly formatted (no quotes are escaped).
Fix#6671
Set the IPv6 adapter IP to be <prefix>::1. Otherwise, guest to host
communication over IPv6 is not routed correctly. This means that
consumers should not specify <prefix>::1 IP addresses to VirtualBox,
which should be a reasonable restriction.
Fixes#6658
Like in the (remote) `ansible` provisioner, it is preferred to pass the
directory that contains the generated inventory file. This way, advanced
inventory usages can be achieved by adding more inventory files into the
same directory.
Related to #2103 and #6500
[ci skip]
Vagrant should only consider the host-only interfaces used by the
virtual machine in the IPv6 fixup code. There may be other interfaces
present on the system with IPv6 addresses that for various reasons
would fail the routing check (for example, an interface with no
machines attached).
The patch changes the behavior to not scan all of the host-only
interfaces and adds a unit test for the behavior (that the correct IP
is validated).
Lastly, there is a small fix here that may not be an issue for most
people where the IPv6 prefix was asummed to be a multiple of 16 for
the purposes of constructing the UDP probe datagram. This assumption
has been removed.
Fixes#6586