ltsp-update-image - generate an NBD image from an LTSP chroot


ltsp-update-image [OPTION] [CHROOT...]


Generates a compressed squashfs NBD image from an LTSP chroot and exports it with nbd-server. Chroot can be a full path or a subdirectory of the LTSP base directory, and it defaults to the host architecture if unset.


-b, --base[=PATH]

The LTSP base directory Defaults to /opt/ltsp if unspecified.

-c, --cleanup

Temporarily remove user accounts, logs, caches etc from the chroot before exporting the image. The chroot arch is required to be compatible with the server arch.


Compress the resulting image with TYPE (gzip, lzo, xz, lz4). If unspecified, use mksquashfs default.

-e, --exclude[=LIST]

List of dirs/files to exclude from the image. This is in addition to /etc/ltsp/ltsp-update-image.excludes.

-f, --config-nbd

Generate appropriate nbd-server configuration files. It’s automatically set if NFS isn’t used or if other LTSP generated nbd-server configuration files already exist.

-h, --help

Displays the ltsp-update-image help message.

-m, --no-compress

Don’t compress the generated image.

-n, --no-backup

Don’t backup chroot.img to chroot.img.old.

-r, --revert

Swap chroot.img with chroot.img.old and update kernels.


Output version information and exit.


Part of the ltsp package and the latest versions are available in source form from


/etc/ltsp/<tool>.conf: Upon execution the tool will read a configuration file to override built-in defaults.

Values are NAME="VALUE" pairs, with # representing commented lines. most commandline options have an equivalent. an example Debian based system with an alternate base location, architecture, and distribution:

# set alternate default location for ltsp chroot (--base)
# build an amd64 chroot by default (--arch)
# build a Debian sid environment (--dist)

/etc/ltsp/ltsp-server.conf: Each LTSP server tool will read a generic configuration file. This file is typically used for setting BASE, TFTP_DIRS and TFTP_BOOT_DIR. These settings are overwritten by those set in specific tool configs.


Autogenerated from the script source code with help2man. Distributed under the terms of the GNU General Public License version 2 or any later version.


Report bugs to


ltsp-build-client(8), ltsp-update-kernels(8), ltsp-update-sshkeys(8), mksquashfs(1), nbd-server(1)