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nbdkit-tar-plugin(1) NBDKIT nbdkit-tar-plugin(1)

NAME

nbdkit-tar-plugin - read and write files inside tar files without unpacking

SYNOPSIS

 nbdkit tar tar=FILENAME.tar file=PATH_INSIDE_TAR

EXAMPLE

Serve a single file inside a tarball

 nbdkit tar tar=file.tar file=some/disk.img
 guestfish --format=raw -a nbd://localhost

Opening a disk image inside an OVA file

The popular "Open Virtual Appliance" (OVA) format is really an uncompressed tar file containing (usually) VMDK-format files, so you could access one file in an OVA like this: 

 $ tar tf rhel.ova
 rhel.ovf
 rhel-disk1.vmdk
 rhel.mf
 $ nbdkit -r tar tar=rhel.ova file=rhel-disk1.vmdk
 $ guestfish --ro --format=vmdk -a nbd://localhost

DESCRIPTION

"nbdkit-tar-plugin" is a plugin which can read and writes files inside an uncompressed tar file without unpacking the tar file.

The "tar" and "file" parameters are required, specifying the name of the uncompressed tar file and the exact path of the file within the tar file to access as a disk image.

This plugin will not work on compressed tar files.

Use the nbdkit -r flag to open the file readonly. This is the safest option because it guarantees that the tar file will not be modified. Without -r writes will modify the tar file.

Also writing to the tar file does not change data checksums stored in other files (the "rhel.mf" file in the example above), and as these will become incorrect you probably won't be able to open the file with another tool afterwards.

The disk image cannot be resized.

SEE ALSO

https://github.com/libguestfs/nbdkit/blob/master/plugins/tar/tar.pl, nbdkit(1), nbdkit-plugin(3), nbdkit-perl-plugin(3).

AUTHORS

Richard W.M. Jones.

Based on the virt-v2v OVA importer written by Tomáš Golembiovský.

COPYRIGHT

Copyright (C) 2017 Red Hat Inc.

LICENSE

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

2019-01-26 nbdkit-1.10.3