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.\" Title: systemd-nspawn
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.\" Author: Lennart Poettering <lennart@poettering.net>
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.\" Manual: systemd-nspawn
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.TH "SYSTEMD\-NSPAWN" "1" "03/16/2012" "systemd" "systemd-nspawn"
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.\" http://bugs.debian.org/507673
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systemd-nspawn \- Spawn a namespace container for debugging, testing and building
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.HP \w'\fBsystemd\-nspawn\ \fR\fB[OPTIONS...]\fR\fB\ \fR\fB[COMMAND]\fR\fB\ \fR\fB[ARGS...]\fR\ 'u
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\fBsystemd\-nspawn \fR\fB[OPTIONS...]\fR\fB \fR\fB[COMMAND]\fR\fB \fR\fB[ARGS...]\fR
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may be used to run a command or OS in a light\-weight namespace container\&. In many ways it is similar to
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\fBchroot\fR(1), but more powerful since it fully virtualizes the file system hierarchy, as well as the process tree, the various IPC subsystems and the host and domain name\&.
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limits access to various kernel interfaces in the container to read\-only, such as
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/sys/fs/selinux\&. Network interfaces and the system clock may not be changed from within the container\&. Device nodes may not be created\&. The host system cannot be rebooted and kernel modules may not be loaded from within the container\&.
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Note that even though these security precautions are taken
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is not suitable for secure container setups\&. Many of the security features may be circumvented and are hence primarily useful to avoid accidental changes to the host system from the container\&. The intended use of this program is debugging and testing as well as building of packages, distributions and software involved with boot and systems management\&.
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may be used to boot full Linux\-based operating systems in a container\&.
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to set up an OS directory tree suitable as file system hierarchy for
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will mount file systems private to the container to
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and similar\&. These will not be visible outside of the container, and their contents will be lost when the container exits\&.
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containers from the same directory tree will not make processes in them see each other\&. The PID namespace separation of the two containers is complete and the containers will share very few runtime objects except for the underlying file system\&.
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If no arguments are passed the container is set up and a shell started in it, otherwise the passed command and arguments are executed in it\&. The following options are understood:
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\fB\-\-help\fR, \fB\-h\fR
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Prints a short help text and exits\&.
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\fB\-\-directory=\fR, \fB\-D\fR
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Directory to use as file system root for the namespace container\&. If omitted the current directory will be used\&.
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\fB\-\-user=\fR, \fB\-u\fR
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Run the command under specified user, create home directory and cd into it\&. As rest of systemd\-nspawn, this is not the security feature and limits against accidental changes only\&.
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\fB\-\-private\-network\fR
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Turn off networking in the container\&. This makes all network interfaces unavailable in the container, with the exception of the loopback device\&.
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# debootstrap \-\-arch=amd64 unstable debian\-tree/
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# systemd\-nspawn \-D debian\-tree/
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This installs a minimal Debian unstable distribution into the directory
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and then spawns a shell in a namespace container in it\&.
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# systemd\-nspawn \-D /var/lib/mock/fedora\-rawhide\-x86_64/root/ /sbin/init systemd\&.log_level=debug
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This installs a minimal Fedora distribution into a subdirectory of
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and then boots an OS in a namespace container in it, with systemd as init system, configured for debug logging\&.
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The exit code of the program executed in the container is returned\&.
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\fBdebootstrap\fR(8),
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\fBLennart Poettering\fR <\&lennart@poettering\&.net\&>