X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=man%2Fsystemd-nspawn.xml;h=ca99da4909cac88b654779a86d0508945ec53f64;hb=672682a6b9d6fb6a3722c3fea1a93b4831747b54;hp=a80cec4e6c62d8c781fa54cdbe88359e15bc3264;hpb=f03dc7c0c58c5cddb62dbd809c1f4ccad3c6e2b6;p=elogind.git diff --git a/man/systemd-nspawn.xml b/man/systemd-nspawn.xml index a80cec4e6..ca99da490 100644 --- a/man/systemd-nspawn.xml +++ b/man/systemd-nspawn.xml @@ -97,14 +97,13 @@ 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, - debootstrap8 + debootstrap8, or pacman8 to set up an OS directory tree suitable as file system @@ -124,15 +123,37 @@ 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. It is however possible to - enter an existing container, see - Example 4 below. - + 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 /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. @@ -171,7 +192,7 @@ Directory to use as file system root for the namespace - container. If omitted the current + container. If omitted, the current directory will be used. @@ -212,15 +233,46 @@ host, and is used to initialize the container's hostname (which the container can choose to override, - however). If not specified the last + 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. + + + + + + + + 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. + + + - Set the specified uuid + Set the specified UUID for the container. The init system will initialize /etc/machine-id @@ -228,16 +280,6 @@ - - - - - Makes the container appear in - other hierarchies than the name=systemd:/ one. - Takes a comma-separated list of controllers. - - - @@ -252,7 +294,7 @@ Mount the root file - system read only for the + system read-only for the container. @@ -261,7 +303,7 @@ 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 @@ -282,12 +324,22 @@ CAP_AUDIT_CONTROL. + + + + 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 + visible to the host system. If enabled, allows viewing the container's journal files from the host (but not vice versa). Takes one of @@ -313,7 +365,7 @@ /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 @@ -349,6 +401,54 @@ creates read-only bind mount. + + + + + 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. + + + + + + + Turns off any status + output by the tool itself. When this + switch is used, then the only output + by nspawn will be the console output + of the container OS + itself. + + + + + + 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. + + @@ -360,7 +460,7 @@ # 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. @@ -388,22 +488,35 @@ 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. + # 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. + + + + + Example 5 + + # btrfs subvolume snapshot / /.tmp +# systemd-nspawn --private-network -D /.tmp -b + + This runs a copy of the host system in a + btrfs snapshot. + + + + Example 6 - # nsenter -m -u -i -n -p -t $PID + # 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 - nsenter1 - is part of - util-linux. - Kernel support for entering namespaces was added in - Linux 3.8. + This runs a container with SELinux sandbox security contexts. @@ -418,10 +531,11 @@ systemd1, chroot1, - unshare1, yum8, debootstrap8, - pacman8 + pacman8, + systemd.slice5, + machinectl1