m23 logo

m23 is a free software distribution system licensed under the GPL, which installs and administers clients with

m23 is controlled via webbrowser. The installation of a new m23 client is done in only three steps and the integration of existing clients is possible, too. Group functions and mass installation tools make managing a vast number of clients comfortable. Client backup and server backup are included to avoid data loss. With the integrated virtualisation software, m23 can create and manage virtual m23 clients, that run on real m23 clients or the m23 server. Scripts and software packages (for installation on the clients) can be created directly from the m23 web interface.


m23 features

Administration via webbrowser

The entire administration is done via webbrowser and is possible from all computers having access to the m23 server via network. The installation of additional administration software is not necessary. A remote access to the m23 server via PDA or laptop is easily possible. Authentification and SSL encryption secure the communication and prevent undesirable access.

Three steps to your complete client

Installing a client with m23 is rather simple. Only three steps are required for a completely installed client.

1. Adding the client
Screenshot: Add client

First, you need to enter some values for the client. These are, for example, the network settings (IP, networkmask, etc.), user name and password or the name of an LDAP server that manages your user accounts.

2. Partitioning, formatting and installation of the operating system
Screenshot: Client partitioning and formatting

All clients can be partitioned and formatted individually. The resulting partitions can be used for the installation of the operating system, the creation of software RAIDs, for data storage or as swap space. The installation will start after the selection of the operating system.

3. Installation of additional software
Screenshot: add more packages

You can install additional software packages in the last (optional) step.

Integration of existing clients into m23

In addition to the bare metal installation on physical or virtual client system, including partitioning and formatting, existing, Debian-based systems (Debian, Ubuntu, Kubuntu, Xubuntu, Linux Mint, Elementary OS) can be integrated into the m23 environment, to simplify further administration ((de)installation and updating of packages).

Group functions

You will like the convenient group functions if you have a big amount of clients that need to install new software or if other routine jobs need to be done. E.g. a new software package can be installed on all clients or be removed from all clients of a group. In addition, an update or a client recovery can be accomplished on all group members. An arbitrary number of groups can be created, where each client can simultaneously be a member in an arbitrary number of groups.

Mass installation

The mass installation tools are handy, if you need to install a big amount of clients with similar requirements (and maybe different hardware). The mass installation is done in three steps.

1. Creation of a defined client
Screenshot: Define client model

A model client, that holds the basic settings (such as the default gateway or the group name), is defined (but not installed). The real clients are to be derived from this defined client. The defined client gets a partitioning and formatting for its virtual harddrive (as well as rules what to do if the real harddrives are differing in size or type), the operation system and appropriate software packages.

2. Choosing the parameter generator options
Screenshot: Select generation method for parameters

Now you have to choose which of the settings, that can or have to be different on each client, shall be kept (e.g. user name), generated automatically (e.g. client name) or read from a file or entered by hand (e.g. MAC address). The partitioning of the virtual harddisk will be adjusted on client deployment.

3. Final review of the client parameters
Screenshot: Review generated parameters

In this last step you see all the parameters and values of all clients in a table and you can change the values by hand. It is possible to change the number of clients, too. Automatically generated client parameters will be calculated in the required amount or existing clients will be removed.

Client features

Operating systems

m23 supports:

m23 supports Debian, Ubuntu, Kubuntu, Xubuntu, Fedora, Linux Mint, elementary OS, CentOS and openSUSE. The choice of the Linux distribution is a matter of taste and a question of the functional range. m23 gives the administrator the chance to choose the right distribution for each client individually which can be installed automatically. m23 allows to manages all clients via the same m23 administration interface, no matter which distribution is installed.

Free partitioning and formatting

In addition to the automatic partitioning and formatting, m23 supports individual harddrive setups. The resulting partitions can be used for the operating system, to store data and for swapping. The m23 interface includes all necessary functions for deleting, adding and formatting of partitions and for assigning them to mountpoints, installation or swap usage. In addition, it is possible to reuse the existing partition layout for the installation.

Support for software RAIDs

Partitions or entire harddrives can be combined into software RAIDs. m23 supports the RAID levels 0, 1, 4, 5, 6 and 10. These RAID levels have advantages and disadvantages in relation to speed increase and data reliability. RAIDs can be used like normal partitions to install operating systems to or to use them as swap or storage space. You can install the Linux kernel and its modules on a separate (non-RAID) partition to be able to install an operating system on all possible RAID levels.

User management with LDAP

User accounts can be managed with a central LDAP server. This increases the ease of use in environments with many clients and a lot of users. The OpenLDAP server is shipped with the m23 server and can be administered via the highly integrated phpLDAPadmin. m23 can use existing LDAP entries for new m23 clients or add extra entries on adding an m23 client.

NFS for storing home directories

An NFS server for storing the user's home directories is a good supplement to an existing LDAP server. Using an NFS server simplifies the making of backups dramatically in contrast to a lot of clients storing the home directories on local harddrives. As a benefit of this combination the user has the alternative to log in into any client and find her or his own desktop and files.

Software packages

Thousands of software packages like office packages, graphic tools, server applications or games can be installed via the webinterface. Software installation or removal jobs are carried out at boot time or while the client is in normal use.

Software choice in different distributions

The Linux distributions that are installable with m23 offer a large variety of free software, which can be installed easily. In addition to the package sources recommended by m23 other package sources can be added to install software from other suppliers.

Package dependency check

You can check if the removal or installation of software will be sucessful before the actual process. The administration interface gives a warning message, e.g. if a package can not be installed due to unsolved dependencies.

Automatic software package caching

Software packages are downloaded from the internet to keep them up-to-date. The packages are then cached to ensure that every package is downloaded only once. If a certain package is installed a second time, the package will be installed from the cache. In case that a new version of the package exists, the latest package will first be downloaded and stored in the cache. On your m23 server this job is done by the proxy cache Squid.

Pool builder for building package sources

The pool builder makes it possible to combine software packages from different media (CD, DVD, internet) on the m23 server and convert them to a package source. These package sources can be used to install clients. This can be done without an internet connection or if the internet connection is rather slow. It is possible, too, to add selfmade packages to the pool.

Package builder

Debian packages can be created from compressed tar files from the m23 interface. These packages are then available for installation on the m23 clients.

Efficient file transfer using BitTorrent

To efficiently deploy large files to any number of m23 clients, the m23 api offers functions making use of BitTorrent. The m23 clients exchange parts of the files deployed with BitTorrent among each other, in the optimal case resulting in each file being only deployed once from the m23 server. A possible use case would be to deploy a virtual applicance to a set of systems used for training in an educational environment.

Package selections

Packages which will always be installed (or removed) together can be grouped to a package selection. These package selections can be used for single clients, groups of clients or directly during installation of the operating system.

Script editor

Scripts for any kind of client jobs can be created using the integrated script editor in the m23 interface. The full range of functions of the m23 api is available for use in these scripts.

Configuration management

m23 offers several options for configuring the m23 clients. Many settings can be adapted by using the debconf dialogs that are imported into the m23 interface from the distributions' packages. Alternatively, client scripts can make use of the file editing functions provided by the m23 api, to perform any kind of configuration task. If that's not yet enough, one can, of course, also use one's favourite configuration tool, e.g. (R)?ex, Chef, Cfengine (, awk, sed), git, subversion or cvs.

Graphical desktops

Support for:

The m23 clients can be installed as workstation with the graphical user interfaces KDE, Gnome, XFce, LXDE, Unity, Mate, TDE, Cinnamon, Pantheon and pure X11 or as a server without graphical subsystem. In most server setups, the server doesn't need a user interface because most of the server software runs in text mode. If you choose the Ubuntu distribution you can also install Unity, for Linux Mint Mate or Cinnamon, for Kubuntu "Kubuntu desktop" (KDE based) and for elementary OS, there is the Pantheon desktop.

Imaging: Installation using image files

An image file of a partition or entire harddisk can be used to install other clients. These image files are taken from installed clients with all their software packages and settings. The creation of these image files is included in the m23 administration interface for your comfort. Image files can be compressed to save storage space and bandwidth on rollout. An image file can be used to install any number of clients. After the end of the transfer, the client will be adjusted like a client that was installed from software packages. This is done on Debian, Ubuntu, Kubuntu and Xubuntu clients. These "image clients" can be managed like "normal clients" with m23, this includes software installation and other administrative tasks.

Client backup


Personal data and additional settings can be backupped and restored with the integrated software BackupPC. This is necessary for all personal data which is not handled by m23.

Client recovery

A client can be reinstalled with excactly the same software selection and configuration as it was installed with m23 before. This is done with the recovery feature directly from the m23 interface. The recovery includes the complete installation with partitioning and formatting. All settings done with m23 will be restored. Manual changes need a recovery from a backup medium.

Rescue system

The m23 rescue system is a minimal Linux environment that can be booted on the clients via the network. You can use it for on-location maintenance or via an SSH console. The administrator has full access to the client and can do all administrative work. Additional tools (e.g. the client log) support the administrator with his/her fault analysis.

Client virtualisation


The free virtualisation solution VirtualBox OSE is now (optional) part of m23 and can be installed directly on the m23 server as well as on the managed m23 clients. Required for virtualisation is a current Debian system (Debian Lenny or Squeeze). Virtual m23 clients which act on the network just like normal m23 clients are managed via the m23 server as usual. These virtual clients can be partitioned and formatted like a normal PC and of course the operating system and additional software can be installed as well. Access to the VMs' desktops is (optionally) possible by using x2go.

VirtualBox OSE packages are available for 32 and 64 bit machines, that can be installed directly via the m23 web interface on the m23 clients. These m23 clients are virtualisation hosts for virtual m23 clients after the installation. Virtualisation may be useful to use the existing ressources of your computers better (e.g. office PCs that usually wait for user input most of the time or on a web server).

Screenshot: Installation on a virtual client

You can check the usage of harddisk and memory on the virtualisation host in the "VM creation dialog" before you create a new virtual m23 client. So you can take care not to assign too much harddisk space or memory to the VM. The newly created VM runs through the usual 3-step-setup after the creation is done.

Virtual m23 clients can run in graphical mode or without visible output. A modified VNC server was integrated for the graphical output to replace the VRDP feature of the non-free VirtualBox edition. It can be used to access the virtual clients from the boot on and allows to engage if problems occur. The VNC session contains the VirtualBox window with the running virtual m23 client and is based on the lightweight window manager flwm. An analog clock, a terminal and a button to shut down the session together with the VirtualBox machine are visible too.

Improve m23

The m23 interface and the entire m23 system can be improved with extra functions.

The MDK (m23 Development Kit) is a powerful environment to adjust m23 to your needs. E.g. you can create your own m23 server installation CD or build new network boot images with new modules.

Using the m23 extension halfSister, the ambitious administrator can easily make his or her favourite Linux distribution installable with m23, like it was already done with CentOS, openSUSE and Fedora.

Server features

The m23 server can be installed on different system architectures. For x86 systems (physical or virtual), there is the m23 server installation ISO file. For virtualization software, there is a VM appliance in the OVA file format. For RaspberryPi, there's an image that can be written to an SD card, and for Debian, there are architecture-independent packages. Additionally, m23 is available as an 'app' in Univention's UCS App Center.

m23 server components

The m23 server is based upon Debian, or, in the case of the RaspberryPi, Raspbian. It uses Apache, PHP and MySQL to provide the m23 web interface and to generate bash scripts that will be executed on the clients on-demand. Furthermore, it comprises a DHCP and a TFTP server, which are required for network boot and for assigning network settings later. The Squid proxy ensures that each package will only be downloaded from the internet once, in case of using the publicly accessible package sources. BackupPC can be used to create backups of personal data and additional settings which are not taken care of by m23 directly. The preconfigured OpenLDAP server can be used for centralized management of user accounts for the m23 clients.

m23 command line interface

The modular m23 command line interface (m23cli) provides an additional way to request status information for the m23 clients and to execute administrative jobs. This can be harnessed for automatization by use of own scripts.

Server backup

Server backup

The server backup function stores the m23 server with all its data at given points in time. The backups contain all information necessary to restore the whole m23 server functionality. Multiple points in time can be selected for this purpose. GPG encrypted backup files can be transferred to external servers automatically.

A GPG key management was integrated into the m23 webinterface, too. After a data fault the restore script will first install an "empty" m23 server and use the backup to bring it into a previously saved state. A short guide showing the restoring steps can be printed out directly from the m23 web interface (and should be before an emergency occurs!).

Variable firewall

A variable firewall makes sure that only safe values will be handed to the database. This should prevent SQL injection attacs.

IP manager

The IP management allows you to connect network settings to a MAC address, so that the necessary values are sent to the respective device via DHCP. Aside from this direct assignment, IP ranges can be defined, within which the IPs can be assigned dynamically (e.g. to notebooks). Specific settings (e.g. client name, MAC address) or specific IP ranges can now be blocked, so m23 cannot wrongly use these for m23 clients.

How it works

m23 differentiates between the server and the clients. The m23 server is tasked with the deployment of software and client management. Clients are the systems which are managed by the m23 server, so those where the software will be installed.

Diagram of operation principles

The installation of an operating system on an m23 client, which can take on the role of a (web/file/...) server or a desktop work station, will be started by booting via network (PXE), or using a boot CD / flash drive. The client's hardware will automatically be recognized and configured. After the hardware recognition has terminated successfully, the detected hardware and partition info will be sent to the server, and displayed in the m23 web interface, where the administrator can now make the settings for formatting and partitioning of the hard drive. The administrator will now also select further attributes, e.g. the distribution, desktop, kernel and package selections to install on the client. When the installation of the operating system, which, aside from a base system, uses the packages of the corresponding distribution, has terminated, further administrative tasks (e.g. (de)installation of packages, updates, backups etc.) can be executed.

Communication between the m23 client and the m23 server

Communication between the m23 client and the m23 server

Generation of scripts

The bash scripts executed on the clients are dynamically created from PHP code by the m23 server.

Script generation

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