[Libguestfs] Question: running appliance commands over guest fs (resize2fs -P).

[Richard W.M. Jones]

On Tue, Sep 15, 2015 at 05:17:16PM +0300, Maxim Perevedentsev wrote:
> On 09/15/2015 04:57 PM, Richard W.M. Jones wrote:
> >>2) More general, how to execute commands from appliance but make
> >>them run over image (which may not have anything but filesystem) - I
> >>saw something like that in source.
> >Not sure I understand the question?
>
> As I understand, guestfs runs its own kernel-like daemon that can
> run its own commands. It is used to run e.g. resize2fs or e2fsck
> over loaded disk images. But those two utilities require the
> partition not to be mounted, so they are run by daemon and do not
> require anything to exists on partition.
> 
> In API I found only the 'command' command which requires the
> partition to be mounted and have kernel image on it. This cannot
> operate on empty or non-mounted partition.

You probably want to use the guestfs_debug API, ie:

  char *cmd[] = { "resize2fs", "-P", ..., NULL };
  char *ret = guestfs_debug (g, "sh", cmd);

It's better to add a new API however, and not difficult either:

  http://libguestfs.org/guestfs.3.html#adding-a-new-api-action

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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