disk/vfs: ensure guestfs capabilities

[OpenStack Infra]

https://review.openstack.org/120467
commit 6a0e6209cab2ced467b63ce9ce69a41daae669fe
Author: Sahid Orentino Ferdjaoui <email address hidden>
Date: Wed Sep 10 16:05:22 2014 +0000

    disk/vfs: ensure guestfs capabilities

    Ensures that guestfs is available and well configured. Also
    when checking for capabilities this commit introduces an in-memory
    flag to avoid repeating the process if succeeded.
    If we are able to load guestfs but something wrong happens a fatal
    error is raised.

    DocImpact: We should add a not for ubuntu like systems that use
    libguestfs to execute the command 'update-guestfs-appliance' for
    configuring it.

    Closes-Bug: #1275267
    Closes-Bug: #1157922
    Change-Id: I97b3a23829ea1f3aadfe08ca6448b35010d2f312

[Sahid Orentino (sahid-ferdjaoui)]

More information here from Richard W.M. Jones:

 - 'sudo update-guestfs-appliance' goes away with libguestfs >= 1.26
   in Debian & Ubuntu, where, finally, they have got rid of that daft
   script, and the appliance gets built automatically on demand, as
   happens on Fedora and everywhere else.

 - However Ubuntu does still have the kernel permissions problem, and
   this will probably stay this way forever, since we haven't managed
   to persuade them that what they are doing is stupid.

So since the situation is fluid, perhaps it's better just to link to
the FAQ?

http://libguestfs.org/guestfs-faq.1.html#downloading-installing-compiling-libguestfs

[Tom Fifield (fifieldt)]

@Matt - I think you fixed this in the install guide, right?

[Matt Kassawara (ionosphere80)]

Juno appears to work with or without libguestfs and the installation guide appears correct.