X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd-nspawn.xml;h=7d450f912c1c617c17d6bd41a32eb0d87374963a;hp=777e0a3a77ba0ead624e29111ade46477892c9da;hb=d1b38fac57d82f0249b9e581eb0d18175f6aa74a;hpb=2b3987a863975f5a1fa1754725e3d07a5d4f6478 diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml index 777e0a3a7..7d450f912 100644 --- a/man/systemd-nspawn.xml +++ b/man/systemd-nspawn.xml @@ -49,7 +49,17 @@ - systemd-nspawn OPTIONS COMMAND ARGS + systemd-nspawn + OPTIONS + COMMAND + ARGS + + + + systemd-nspawn + -b + OPTIONS + ARGS @@ -87,15 +97,15 @@ involved with boot and systems management. In contrast to - chroot1 - systemd-nspawn may be used to boot - full Linux-based operating systems in a - container. + chroot1 systemd-nspawn + may be used to boot full Linux-based operating systems + in a container. Use a tool like - yum8 + yum8, + debootstrap8, or - debootstrap8 + pacman8 to set up an OS directory tree suitable as file system hierarchy for systemd-nspawn containers. @@ -113,26 +123,57 @@ 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. + underlying file system. It is however possible to + enter an existing container, see + Example 4 below. + systemd-nspawn implements the Container Interface specification. + + As a safety check + systemd-nspawn will verify the + existence of /etc/os-release in + the container tree before starting the container (see + os-release5). It + might be necessary to add this file to the container + tree manually if the OS of the container is too old to + contain this file out-of-the-box. + + + + Incompatibility with Auditing + + Note that the kernel auditing subsystem is + currently broken when used together with + containers. We hence recommend turning it off entirely + by booting with audit=0 on the + kernel command line, or by turning it off at kernel + build time. If auditing is enabled in the kernel, + operating systems booted in an nspawn container might + refuse log-in attempts. Options - 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: + If option is specified, the + arguments are used as arguments for the init + binary. Otherwise, COMMAND + specifies the program to launch in the container, and + the remaining arguments are used as arguments for this + program. If is not used and no + arguments are specifed, a shell is launched in the + container. + + The following options are understood: - + Prints a short help text and exits. @@ -146,29 +187,32 @@ - + Directory to use as file system root for the namespace - container. If omitted the current + container. If omitted, the current directory will be used. - + Automatically search for an init binary and invoke it instead of a shell or a user supplied - program. + program. If this option is used, arguments + specified on the command line are used + as arguments for the init binary. + - + Run the command under specified user, create home @@ -179,10 +223,35 @@ + + + + + Sets the machine name + for this container. This name may be + used to identify this container on the + host, and is used to initialize the + container's hostname (which the + container can choose to override, + however). If not specified, the last + component of the root directory of the + container is used. + + + + + + Make the container + part of the specified slice, instead + of the + machine.slice. + + + - Set the specified uuid + Set the specified UUID for the container. The init system will initialize /etc/machine-id @@ -190,16 +259,6 @@ - - - - - Makes the container appear in - other hierarchies than the name=systemd:/ one. - Takes a comma-separated list of controllers. - - - @@ -214,7 +273,7 @@ Mount the root file - system read only for the + system read-only for the container. @@ -223,7 +282,7 @@ List one or more additional capabilities to grant the - container. Takes a comma separated + container. Takes a comma-separated list of capability names, see capabilities7 for more information. Note that the @@ -249,7 +308,7 @@ Control whether the container's journal shall be made - visible to the host system. If enabled + visible to the host system. If enabled, allows viewing the container's journal files from the host (but not vice versa). Takes one of @@ -261,13 +320,13 @@ not linked. If host, the journal files are stored on the host file system (beneath - /var/log/journal/<machine-id>) + /var/log/journal/machine-id) and the subdirectory is bind-mounted into the container at the same location. If guest, the journal files are stored on the guest file system (beneath - /var/log/journal/<machine-id>) + /var/log/journal/machine-id) and the subdirectory is symlinked into the host at the same location. If auto (the default), @@ -275,7 +334,7 @@ /var/log/journal exists, it will be bind mounted into the container. If the - subdirectory doesn't exist, no + subdirectory does not exist, no linking is performed. Effectively, booting a container once with guest or @@ -291,6 +350,26 @@ Equivalent to . + + + + + + Bind mount a file or + directory from the host into the + container. Either takes a path + argument -- in which case the + specified path will be mounted from + the host to the same path in the + container --, or a colon-separated + pair of paths -- in which case the + first specified path is the source in + the host, and the second path is the + destination in the container. The + option + creates read-only bind + mount. + @@ -302,7 +381,7 @@ # systemd-nspawn -bD /srv/mycontainer This installs a minimal Fedora distribution into - the directory /srv/mycontainer/ and + the directory /srv/mycontainer/ and then boots an OS in a namespace container in it. @@ -317,7 +396,35 @@ distribution into the directory ~/debian-tree/ and then spawns a shell in a namespace container in it. + + + + Example 3 + + # pacstrap -c -d ~/arch-tree/ base +# systemd-nspawn -bD ~/arch-tree/ + + This installs a mimimal Arch Linux distribution into + the directory ~/arch-tree/ and then + boots an OS in a namespace container in it. + + + + Example 4 + + To enter the container, PID of one of the + processes sharing the new namespaces must be used. + systemd-nspawn prints the PID + (as viewed from the outside) of the launched process, + and it can be used to enter the container. + + # nsenter -m -u -i -n -p -t $PID + nsenter1 + is part of + util-linux. + Kernel support for entering namespaces was added in + Linux 3.8. @@ -332,8 +439,11 @@ systemd1, chroot1, + unshare1, yum8, - debootstrap8 + debootstrap8, + pacman8, + systemd.slice5