CONTAINER-SHELL(1)

NAME
container-shell - Manage systemd-nspawn containers (shell)

SYNOPSIS
container-shell ['OPTIONS']
cntsh ['OPTIONS']

DESCRIPTION

compute-tools provides the system integration for managing containers using systemd-nspawn.

  Usage

Although the container-shell can be started from a running system like any other program, the main intend is to use the container-shell via SSH. That way otherwise unprivileged users have possibility to manage containers without needing a regular shell login on the container server.

For usage over SSH a unprivileged user should be created:
sudo adduser --gecos "compute-tools,,," \
--home /var/lib/open-infrastructure/container-shell \
--shell /usr/bin/container-shell

The container-shell can then be allowed for specific SSH keys via /var/lib/compute-tools/container-shell/.ssh/authorized_keys like so:
command="/usr/bin/container-shell",no-port-forwarding,no-X11-forwarding,\
no-agent-forwarding,no-pty ssh-ed25519 [...]

  Restricted shell

The container-shell by default grants any user that has access to it to use all available container commands.

Through two corresponding environment variables users can be allowed or disallowed to use specific container commands. In connection with SSH this makes it possible to grant certain SSH keys (and by that, users) privileges to operate container servers without having to give them root access, a login shell at all and prevents them from doing things they are not trusted to do.

  Example (blacklisting)

In order to allow all commands except for removing and stopping containers, the following variable can be used:
command="CONTAINER_COMMANDS_DISABLE='remove stop' \
/usr/bin/container-shell",no-port-forwarding,no-X11-forwarding,\
no-agent-forwarding,no-pty ssh-ed25519 [...]

  Example (whitelisting)

The other way around works too. To disallow all commands except for listing containers and showing the compute-tools version, the following variable can be used:
command="CONTAINER_COMMANDS_ENABLE='list version' \
/usr/bin/container-shell",no-port-forwarding,no-X11-forwarding,\
no-agent-forwarding,no-pty ssh-ed25519 [...]

COMMANDS

All container commands are available, see container(1). Additionally, the following commands are specific to container-shell:

about:
    Shows introduction (manpage).

help:
    Shows available commands within the container-shell.

help COMMAND:
    Shows help (manpage) for a specific container command.

logout, exit:
    Exits container-shell.

SEE ALSO
compute-tools(7),
container(1).

HOMEPAGE

More information about compute-tools and the Open Infrastructure project can be found on the homepage (https://open-infrastructure.net).

CONTACT

Bug reports, feature requests, help, patches, support and everything else are welcome on the Open Infrastructure Software Mailing List <software@lists.open-infrastructure.net>.

Debian specific bugs can also be reported in the Debian Bug Tracking System (https://bugs.debian.org).

AUTHORS

compute-tools were written by Daniel Baumann <daniel.baumann@open-infrastructure.net> and others.