X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd-nspawn.xml;h=b3a2d328559273a6feccc01114ca7e562e419e98;hp=2a26b1ef18e51d241b577314cb1246345b9dd18c;hb=9700d6980f7c212b10a69399e6430b82a6f45587;hpb=5430f7f2bc7330f3088b894166bf3524a067e3d8 diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml index 2a26b1ef1..b3a2d3285 100644 --- a/man/systemd-nspawn.xml +++ b/man/systemd-nspawn.xml @@ -21,7 +21,8 @@ along with systemd; If not, see . --> - + systemd-nspawn @@ -49,7 +50,17 @@ - systemd-nspawn OPTIONS COMMAND ARGS + systemd-nspawn + OPTIONS + COMMAND + ARGS + + + + systemd-nspawn + -b + OPTIONS + ARGS @@ -59,7 +70,7 @@ systemd-nspawn may be used to run a command or OS in a light-weight namespace container. In many ways it is similar to - chroot1, + chroot1, 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 @@ -87,15 +98,18 @@ 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 - debootstrap8 or mock1 + yum8, + debootstrap8, + or + pacman8 to set up an OS directory tree suitable as file system - hierarchy for systemd-nspawn containers. + hierarchy for systemd-nspawn + containers. Note that systemd-nspawn will mount file systems private to the container to @@ -110,89 +124,640 @@ 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. Use + machinectl1's + login command to request an + additional login prompt in a running container. + + systemd-nspawn implements the + Container + Interface specification. + + As a safety check + systemd-nspawn will verify the + existence of /usr/lib/os-release + or /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. 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. + Directory to use as + file system root for the container. If + neither + nor are + specified, the current directory will + be used. May not be specified together with + . - - + + + + Disk image to mount + the root directory for the container + from. Takes a path to a regular file + or to a block device node. The file or + block device must contain a GUID + Partition Table with a root partition + which is mounted as the root directory + of the container. Optionally, it may + contain a home and/or a server data + partition which are mounted to the + appropriate places in the + container. All these partitions must + be identified by the partition types + defined by the Discoverable + Partitions Specification. Any + other partitions, such as foreign + partitions, swap partitions or EFI + system partitions are not mounted. May + not be specified together with + . + - Directory to use as - file system root for the namespace - 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. If this option is used, + arguments specified on the command + line are used as arguments for the + init binary. This option may not be + combined with + . + - + - 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. + After transitioning + into the container, change to the + specified user-defined in the + container's user database. Like all + other systemd-nspawn features, this is + not a security feature and provides + protection against accidental + destructive operations + only. + + + + + + + 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. + + + + + + Set the specified UUID + for the container. The init system + will initialize + /etc/machine-id + from this if this file is not set yet. + + + + Make the container + part of the specified slice, instead + of the default + machine.slice. + + + - Turn off networking in - the container. This makes all network - interfaces unavailable in the - container, with the exception of the - loopback device. + Disconnect networking + of the container from the host. This + makes all network interfaces + unavailable in the container, with the + exception of the loopback device and + those specified with + + and configured with + . If + this option is specified, the + CAP_NET_ADMIN capability will be added + to the set of capabilities the + container retains. The latter may be + disabled by using + . + + + + + + Assign the specified + network interface to the + container. This will remove the + specified interface from the calling + namespace and place it in the + container. When the container + terminates, it is moved back to the + host namespace. Note that + + implies + . This + option may be used more than once to + add multiple network interfaces to the + container. + + + + + + Create a + macvlan interface + of the specified Ethernet network + interface and add it to the + container. A + macvlan interface + is a virtual interface that adds a + second MAC address to an existing + physical Ethernet link. The interface + in the container will be named after + the interface on the host, prefixed + with mv-. Note that + + implies + . This + option may be used more than once to + add multiple network interfaces to the + container. + + + + + + Create a virtual + Ethernet link + (veth) between host + and container. The host side of the + Ethernet link will be available as a + network interface named after the + container's name (as specified with + ), prefixed + with ve-. The + container side of the Ethernet + link will be named + host0. Note that + + implies + . + + + + + + Adds the host side of + the Ethernet link created with + to the + specified bridge. Note that + + implies + . If + this option is used, the host side of + the Ethernet link will use the + vb- prefix instead + of ve-. + + + + + + + Sets the SELinux + security context to be used to label + processes in the container. + + + + + + + + Sets the SELinux security + context to be used to label files in + the virtual API file systems in the + container. + + + + + List one or more + additional capabilities to grant the + container. Takes a comma-separated + list of capability names, see + capabilities7 + for more information. Note that the + following capabilities will be granted + in any way: CAP_CHOWN, + CAP_DAC_OVERRIDE, CAP_DAC_READ_SEARCH, + CAP_FOWNER, CAP_FSETID, CAP_IPC_OWNER, + CAP_KILL, CAP_LEASE, + CAP_LINUX_IMMUTABLE, + CAP_NET_BIND_SERVICE, + CAP_NET_BROADCAST, CAP_NET_RAW, + CAP_SETGID, CAP_SETFCAP, CAP_SETPCAP, + CAP_SETUID, CAP_SYS_ADMIN, + CAP_SYS_CHROOT, CAP_SYS_NICE, + CAP_SYS_PTRACE, CAP_SYS_TTY_CONFIG, + CAP_SYS_RESOURCE, CAP_SYS_BOOT, + CAP_AUDIT_WRITE, + CAP_AUDIT_CONTROL. Also CAP_NET_ADMIN + is retained if + is + specified. If the special value + all is passed, all + capabilities are + retained. + + + + + + Specify one or more + additional capabilities to drop for + the container. This allows running the + container with fewer capabilities than + the default (see above). + + + + + + Control whether the + container's journal shall be made + visible to the host system. If enabled, + allows viewing the container's journal + files from the host (but not vice + versa). Takes one of + no, + host, + guest, + auto. If + no, the journal is + not linked. If host, + the journal files are stored on the + host file system (beneath + /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) + and the subdirectory is symlinked into the host + at the same location. If + auto (the default), + and the right subdirectory of + /var/log/journal + exists, it will be bind mounted + into the container. If the + subdirectory does not exist, no + linking is performed. Effectively, + booting a container once with + guest or + host will link the + journal persistently if further on + the default of auto + is used. + + + + + + Equivalent to + . + + + + + + Mount the root file + system read-only for the + container. + + + + + + + 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 + mounts. + + + + + + Mount a tmpfs file + system into the container. Takes a + single absolute path argument that + specifies where to mount the tmpfs + instance to (in which case the + directory access mode will be chosen + as 0755, owned by root/root), or + optionally a colon-separated pair of + path and mount option string, that is + used for mounting (in which case the + kernel default for access mode and + owner will be chosen, unless otherwise + specified). This option is + particularly useful for mounting + directories such as + /var as tmpfs, to + allow state-less systems, in + particular when combined with + . + + + + + + Specifies an + environment variable assignment to + pass to the init process in the + container, in the format + NAME=VALUE. This + may be used to override the default + variables or to set additional + variables. This parameter may be used + more than once. + + + + + + Allows the container + to share certain system facilities + with the host. More specifically, this + turns off PID namespacing, UTS + namespacing and IPC namespacing, and + thus allows the guest to see and + interact more easily with processes + outside of the container. Note that + using this option makes it impossible + to start up a full Operating System in + the container, as an init system + cannot operate in this mode. It is + only useful to run specific programs + or applications this way, without + involving an init system in the + container. This option implies + . This + option may not be combined with + . + + + + + + Controls whether the + container is registered with + systemd-machined8. Takes + a boolean argument, defaults to + yes. This option + should be enabled when the container + runs a full Operating System (more + specifically: an init system), and is + useful to ensure that the container is + accessible via + machinectl1 + and shown by tools such as + ps1. If + the container does not run an init + system, it is recommended to set this + option to no. Note + that + implies + . + + + + + + + Instead of creating a + transient scope unit to run the + container in, simply register the + service or scope unit + systemd-nspawn has + been invoked in with + systemd-machined8. This + has no effect if + is + used. This switch should be used if + systemd-nspawn is + invoked from within a service unit, + and the service unit's sole purpose + is to run a single + systemd-nspawn + container. This option is not + available if run from a user + session. + + + + + + Control the + architecture ("personality") reported + by + uname2 + in the container. Currently, only + x86 and + x86-64 are + supported. This is useful when running + a 32-bit container on a 64-bit + host. If this setting is not used, + the personality reported in the + container is the same as the one + reported on the + host. + + + + + + + Turns off any status + output by the tool itself. When this + switch is used, the only output + from nspawn will be the console output + of the container OS itself. + + + + =MODE + + Boots the container in + volatile (ephemeral) mode. When no + mode parameter is passed or when mode + is specified as yes + full volatile mode is enabled. This + means the root directory is mounted as + mostly unpopulated + tmpfs instance, and + /usr from the OS + tree is mounted into it, read-only + (the system thus starts up with + read-only OS resources, but pristine + state and configuration, any changes + to the either are lost on + shutdown). When the mode parameter is + specified as state + the OS tree is mounted read-only, but + /var is mounted + as tmpfs instance + into it (the system thus starts up + with read-only OS resources and + configuration, but pristine state, any + changes to the latter are lost on + shutdown). When the mode parameter is + specified as no + (the default) the whole OS tree is made + available writable. + + Note that setting this to + yes or + state will only + work correctly with operating systems + in the container that can boot up with + only /usr + mounted, and are able to populate + /var + automatically, as + needed. + + + + - Example 1 + Examples + + Boot a minimal Fedora distribution in a container - # debootstrap --arch=amd64 unstable debian-tree/ -# systemd-nspawn -D debian-tree/ + # yum -y --releasever=19 --nogpg --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora install systemd passwd yum fedora-release vim-minimal +# systemd-nspawn -bD /srv/mycontainer - This installs a minimal Debian unstable - distribution into the directory - debian-tree/ and then spawns a - shell in a namespace container in it. + This installs a minimal Fedora distribution into + the directory /srv/mycontainer/ and + then boots an OS in a namespace container in + it. + - + + Spawn a shell in a container of a minimal Debian unstable distribution - - Example 2 + # debootstrap --arch=amd64 unstable ~/debian-tree/ +# systemd-nspawn -D ~/debian-tree/ + + This installs a minimal Debian unstable + distribution into the directory + ~/debian-tree/ and then spawns a + shell in a namespace container in it. + + + + Boot a minimal Arch Linux distribution in a container + + # 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. + + + + Enable Arch Linux container on boot + + # mv ~/arch-tree /var/lib/container/arch +# systemctl enable systemd-nspawn@arch.service +# systemctl start systemd-nspawn@arch.service + + This makes the Arch Linux container part of the + multi-user.target on the host. + + + + + Boot into a btrfs snapshot of the host system + + # btrfs subvolume snapshot / /.tmp +# systemd-nspawn --private-network -D /.tmp -b - # mock --init -# systemd-nspawn -D /var/lib/mock/fedora-rawhide-x86_64/root/ /sbin/init systemd.log_level=debug + This runs a copy of the host system in a + btrfs snapshot. + - This installs a minimal Fedora distribution into - a subdirectory of /var/lib/mock/ - and then boots an OS in a namespace container in it, - with systemd as init system, configured for debug - logging. + + Run a container with SELinux sandbox security contexts + # chcon system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -R /srv/container +# systemd-nspawn -L system_u:object_r:svirt_sandbox_file_t:s0:c0,c1 -Z system_u:system_r:svirt_lxc_net_t:s0:c0,c1 -D /srv/container /bin/sh + @@ -206,9 +771,12 @@ See Also systemd1, - chroot1, - debootstrap8, - mock1 + chroot1, + yum8, + debootstrap8, + pacman8, + systemd.slice5, + machinectl1