=encoding utf8

=head1 NAME

virt-bootstrap - Setup root file system for libvirt-based containers

=head1 SYNOPSIS

B<virt-bootstrap> URI DEST [OPTIONS]

=head1 DESCRIPTION

B<virt-bootstrap> is a tool providing an easy way to setup the root
file system for libvirt-based containers. It allows to use either a
tarball containing the file system, an image on a docker registry
or virt-builder template and unpacks it either as a folder or in a

=head2 Supported sources are:

=over 4

=item B<file://F</path/to/rootfs.tar>>

Tar archive which contains root file system

=item B<docker://I<registry>:I<port>/I<image>:I<tag>>

Docker registry

=item B<virt-builder://I<template>>

virt-builder templates

=back

Docker container images are downloaded and the layers are getting cached.
If virt-bootstrap is running with effective UID=0 (root) the layersq
are cached in C</var/cache/virt-bootstrap/docker_images>.
For unprivileged users the C<~/.cache/virt-bootstrap/docker_images> directory
is used. If the environment variable C<XDG_CACHE_HOME> is specified then this
directory is used instead of C<~/.cache>.

The environment variable C<VIRTBOOTSTRAP_TMPDIR> can be used to specify
temporary directory used by virt-bootstrap or default C</tmp> will be used.

=head1 OPTIONS

=over 4

=item B<-f>, B<--format>

Output format of the root file system. Possible values are B<dir>
(default) and B<qcow2>.

=item B<--root-password> ROOT_PASSWORD

This argument will generate hash from B<ROOT_PASSWORD> and insert the
hashed value into C</etc/shadow> in the created root file system.

If the output format is C<qcow2> these modifications are applied in
additional qcow2 disk image.

Note that the C</etc/shadow> file must already exist in the extracted
root file system of the container image and it must have entry for root
user.

=item B<--no-cache>

When this flag is used Docker images will be downloaded in temporary
directory and discarded after the root file system is extracted.

=item B<--status-only>

If this flag is used the log messages will be suppresses and only information
about the current progress will be displayed.

=item B<-q>, B<--quiet>

Show only warning and error messages.

=item B<-d>, B<--debug>

Show debugging output messages.

=item B<-h>, B<--help>

Display command line help summary.

=item B<--version>

Show virt-bootstrap's version number and exit.

=back

=head2 Authentication options for accessing private Docker registry

Note: If B<--username> argument is specified and B<--password> omitted
password prompt will be issued. If B<--username> is omitted the B<--password>
argument will be ignored.

=over 4

=item B<-u>, B<--username> USERNAME

   This argument takes USERNAME to be used to access Docker source registry.

=item B<-p>, B<--password> PASSWORD

This argument takes PASSWORD to be used to access Docker source registry.

=item B<--not-secure>

Don't require HTTPS and verification of certificates when talking to Docker registry.

See L<skopeo(1)/"skopeo copy">

=back

=head2 UID/GID mapping

=over 4

=item B<--uidmap> I<start>:I<target>:I<count>

Shift UIDs of all root file system entries with some offset. This parameter
can be specified multiple times.

Example: C<--uidmap 0:1000:10 --uidmap 500:1500:10>
This will map the UIDs: 0-9 to 1000-1009 and 500-509 to 1500-1509

See L<virt-install(1)/"INSTALLATION OPTIONS">

=item B<--gidmap> I<start>:I<target>:I<count>

Shift GIDs of all root file system entries with some offset. This parameter
can be specified multiple times.

Example: C<--gidmap 0:1000:10 --gidmap 500:1500:10>
This will map the GIDs: 0-9 to 1000-1009 and 500-509 to 1500-1509

See L<virt-install(1)/"INSTALLATION OPTIONS">

=item B<--idmap> I<start>:I<target>:I<count>

Remapping owner and group of all files and directories inside of the
root file system. This parameter can be specified multiple times.

Example: C<--idmap 0:1000:10 --idmap 500:1500:10>
This will map UIDs and GIDs: 0-9 to 1000-1009 and 500-509 to 1500-1509

See L<virt-install(1)/"INSTALLATION OPTIONS">

=back

=head1 USAGE EXAMPLES

=over 4

=item Create root file system using Ubuntu image docker.io registry:

    $ virt-bootstrap docker://ubuntu /tmp/foo

=item Create root file system from image stored on private Docker registry:

    $ virt-bootstrap docker://localhost:5000/ubuntu /tmp/foo \
      --username testuser \
      --password testpassoword \
      --not-secure

=item Apply UIDs/GIDs mapping for root file system entries

    $ virt-bootstrap docker://fedora /tmp/foo \
      --idmap 0:1000:10

This above command will map UIDs/GIDs: B<0>-B<9> to B<1000>-B<1009>

The same result can be achieved with:

    $ virt-bootstrap docker://fedora /tmp/foo \
      --uidmap 0:1000:10 \
      --gidmap 0:1000:10

=item Multiple mapping values can be specified as follows:

    $ virt_bootstrap.py docker://ubuntu /tmp/foo \
      --idmap 0:1000:10 \
      --idmap 500:1500:10

This will map the UID/GIDs:
B<0>-B<9> to B<1000>-B<1009> and B<500>-B<509> to B<1500>-B<1509>

=item Set root password

    $ virt_bootstrap.py docker://opensuse /tmp/foo \
      --root-password secret

The above command will download the C<opensuse> container image and
extract the root file system to C</tmp/foo>. Then it will generate hash
of the string C<secret> and insert it into C</tmp/foo/etc/shadow> file.

    $ virt_bootstrap.py docker://opensuse /tmp/foo \
      --root-password secret \
      -f qcow2

Similarly for B<qcow2> format the container image will be downloaded and
the root file system will be extracted into qcow2 disk images with backing
chains. Then additional qcow2 image will be created with backing file set to
the last layer and the modification of C<shadow> file will be applied
there.

=back

=head1 AUTHOR

Written by Cedric Bosdonnat and  Radostin Stoyanov

=cut