X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=man%2Fsystemd-nspawn.xml;h=b7f3be923dc207f1005e34e73862cbcb94aa0ec4;hp=fef5c2c83a8151336b4069b5ed4f7e9873496f25;hb=4bbfe7ad22b0666e82719e39e40be1c6cbb5cc91;hpb=bb31a4ac1997c189a344caf554f34c6aabc71aa7
diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml
index fef5c2c83..b7f3be923 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 OPTIONSCOMMANDARGS
+ 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 +98,15 @@
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.
+ chroot1Â 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.
@@ -113,69 +124,212 @@
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
+ is specified
+ the directory is determined as
+ /var/lib/machines/
+ suffixed by the machine name as
+ specified with
+ . If
+ neither ,
+ , nor
+ are
+ specified, the current directory will
+ be used. May not be specified together
+ with
+ .
-
-
+
+
+ Directory or
+ btrfs subvolume to
+ use as template for the container's
+ root directory. If this is specified
+ and the container's root directory (as
+ configured by
+ ) does
+ not yet exist it is created as
+ btrfs subvolume and
+ populated from this template
+ tree. Ideally, the specified template
+ path refers to the root of a
+ btrfs subvolume, in
+ which case a simple copy-on-write
+ snapshot is taken, and populating the
+ root directory is instant. If the
+ specified template path does not refer
+ to the root of a
+ btrfs subvolume (or
+ not even to a btrfs
+ file system at all), the tree is
+ copied, which can be substantially
+ more time-consuming. Note that if this
+ option is used the container's root
+ directory (in contrast to the template
+ directory!) must be located on a
+ btrfs file system,
+ so that the btrfs
+ subvolume may be created. May not be
+ specified together with
+ or
+ .
+
- Directory to use as
- file system root for the namespace
- container. If omitted the current
- directory will be
- used.
+
+
+
+
+ If specified, the
+ container is run with a temporary
+ btrfs snapshot of
+ its root directory (as configured with
+ ), that
+ is removed immediately when the
+ container terminates. This option is
+ only supported if the root file system
+ is btrfs. May not
+ be specified together with
+ or
+ .
+
+
+
+
+
+
+ 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 either an
+ MBR partition table with a single
+ partition of type 0x83 that is marked
+ bootable, or a GUID partition table
+ with a root partition which is mounted
+ as the root directory of the
+ container. Optionally, GPT images 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
+ ,
+ or
+ .
-
+ 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. 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 during
+ its runtime (for example in tools like
+ machinectl1
+ and similar), 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 path of the container is
+ used, possibly suffixed with a random
+ identifier in case
+ mode is
+ selected. If the root directory
+ selected is the host's root directory
+ the host's hostname is used as default
+ instead.
- Set the specified uuid
+ Set the specified UUID
for the container. The init system
will initialize
/etc/machine-id
@@ -184,44 +338,196 @@
-
-
+
- Makes the container appear in
- other hierarchies than the name=systemd:/ one.
- Takes a comma-separated list of controllers.
-
+ 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.
+
- Mount the root file
- system read only for the
+
+
+
+ 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
+ ipvlan interface
+ of the specified Ethernet network
+ interface and add it to the
+ container. An
+ ipvlan interface
+ is a virtual interface, similar to a
+ macvlan interface, which
+ uses the same MAC address as the underlying
+ interface. The interface
+ in the container will be named after
+ the interface on the host, prefixed
+ with iv-. 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-.
+
+
+
+
+
+
+ If private networking
+ is enabled, maps an IP port on the
+ host onto an IP port on the
+ container. Takes a protocol specifier
+ (either tcp or
+ udp), separated by
+ a colon from a host port number in the
+ range 1 to 65535, separated by a colon
+ from a container port number in the
+ range from 1 to 65535. The protocol
+ specifier and its separating colon may
+ be omitted, in which case
+ tcp is assumed.
+ The container port number and its
+ colon may be ommitted, in which case
+ the same port as the host port is
+ implied. This option is only supported
+ if private networking is used, such as
+ or
+ .
+
+
+
+
+
+
+ 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
+ container. Takes a comma-separated
list of capability names, see
- capabilities7
+ capabilities7
for more information. Note that the
- following capabilities will be
- granted in any way: CAP_CHOWN,
+ 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,
@@ -232,7 +538,25 @@
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_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).
@@ -240,33 +564,38 @@
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
no,
host,
+ try-host,
guest,
+ try-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>)
+ /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),
+ at the same location. try-host
+ and try-guest do the same
+ but do not fail if the host does not have
+ persistent journalling enabled.
+ If auto (the default),
and the right subdirectory of
/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
@@ -280,35 +609,294 @@
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 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
- # yum --releasever=17 --nogpgcheck --installroot ~/fedora-tree/ install yum passwd vim-minimal rootfiles systemd
-# systemd-nspawn -D ~/fedora-tree /usr/lib/systemd/systemd
+ # yum -y --releasever=21 --nogpg --installroot=/srv/mycontainer --disablerepo='*' --enablerepo=fedora install systemd passwd yum fedora-release vim-minimal
+# systemd-nspawn -bD /srv/mycontainer
- This installs a minimal Fedora distribution into
- the directory ~/fedora-tree/
- and then boots an OS in a namespace container in it,
- with systemd as init system.
-
+ This installs a minimal Fedora distribution into
+ the directory /srv/mycontainer/ and
+ then boots an OS in a namespace container in
+ it.
+
-
- Example 2
+
+ Spawn a shell in a container of a minimal Debian unstable distribution
- # debootstrap --arch=amd64 unstable ~/debian-tree/
+ # 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.
+ 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/machines/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 an ephemeral <literal>btrfs</literal> snapshot of the host system
+
+ # systemd-nspawn -D / -xb
+
+ This runs a copy of the host system in a
+ btrfs snapshot which is
+ removed immediately when the container
+ exits. All file system changes made during
+ runtime will be lost on shutdown,
+ hence.
+
+
+
+ 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
+
@@ -322,9 +910,13 @@
See Alsosystemd1,
- chroot1,
- yum8,
- debootstrap8
+ chroot1,
+ yum8,
+ debootstrap8,
+ pacman8,
+ systemd.slice5,
+ machinectl1,
+ btrfs8