nsenter(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | AUTHORS | SEE ALSO | REPORTING BUGS | AVAILABILITY

NSENTER(1)                    User Commands                   NSENTER(1)

NAME         top

       nsenter - run program in different namespaces

SYNOPSIS         top

       nsenter [options] [program [arguments]]

DESCRIPTION         top

       The nsenter command executes program in the namespace(s) that are
       specified in the command-line options (described below). If
       program is not given, then "${SHELL}" is run (default: /bin/sh).

       Enterable namespaces are:

       mount namespace
           Mounting and unmounting filesystems will not affect the rest
           of the system, except for filesystems which are explicitly
           marked as shared (with mount --make-shared; see
           /proc/self/mountinfo for the shared flag). For further
           details, see mount_namespaces(7) and the discussion of the
           CLONE_NEWNS flag in clone(2).

       UTS namespace
           Setting hostname or domainname will not affect the rest of
           the system. For further details, see uts_namespaces(7).

       IPC namespace
           The process will have an independent namespace for POSIX
           message queues as well as System V message queues, semaphore
           sets and shared memory segments. For further details, see
           ipc_namespaces(7).

       network namespace
           The process will have independent IPv4 and IPv6 stacks, IP
           routing tables, firewall rules, the /proc/net and
           /sys/class/net directory trees, sockets, etc. For further
           details, see network_namespaces(7).

       PID namespace
           Children will have a set of PID to process mappings separate
           from the nsenter process. nsenter will fork by default if
           changing the PID namespace, so that the new program and its
           children share the same PID namespace and are visible to each
           other. If --no-fork is used, the new program will be exec’ed
           without forking. For further details, see pid_namespaces(7).

       user namespace
           The process will have a distinct set of UIDs, GIDs and
           capabilities. For further details, see user_namespaces(7).

       cgroup namespace
           The process will have a virtualized view of
           /proc/self/cgroup, and new cgroup mounts will be rooted at
           the namespace cgroup root. For further details, see
           cgroup_namespaces(7).

       time namespace
           The process can have a distinct view of CLOCK_MONOTONIC
           and/or CLOCK_BOOTTIME which can be changed using
           /proc/self/timens_offsets. For further details, see
           time_namespaces(7).

OPTIONS         top

       Various of the options below that relate to namespaces take an
       optional file argument. This should be one of the
       /proc/[pid]/ns/* files described in namespaces(7), or the
       pathname of a bind mount that was created on one of those files.

       -a, --all
           Enter all namespaces of the target process by the default
           /proc/[pid]/ns/* namespace paths. The default paths to the
           target process namespaces may be overwritten by namespace
           specific options (e.g., --all --mount=[path]).

           The user namespace will be ignored if the same as the
           caller’s current user namespace. It prevents a caller that
           has dropped capabilities from regaining those capabilities
           via a call to setns(). See setns(2) for more details.

       -t, --target PID
           Specify a target process to get contexts from. The paths to
           the contexts specified by pid are:

           /proc/pid/ns/mnt
               the mount namespace

           /proc/pid/ns/uts
               the UTS namespace

           /proc/pid/ns/ipc
               the IPC namespace

           /proc/pid/ns/net
               the network namespace

           /proc/pid/ns/pid
               the PID namespace

           /proc/pid/ns/user
               the user namespace

           /proc/pid/ns/cgroup
               the cgroup namespace

           /proc/pid/ns/time
               the time namespace

           /proc/pid/root
               the root directory

           /proc/pid/cwd
               the working directory respectively

       -m, --mount[=file]
           Enter the mount namespace. If no file is specified, enter the
           mount namespace of the target process. If file is specified,
           enter the mount namespace specified by file.

       -u, --uts[=file]
           Enter the UTS namespace. If no file is specified, enter the
           UTS namespace of the target process. If file is specified,
           enter the UTS namespace specified by file.

       -i, --ipc[=file]
           Enter the IPC namespace. If no file is specified, enter the
           IPC namespace of the target process. If file is specified,
           enter the IPC namespace specified by file.

       -n, --net[=file]
           Enter the network namespace. If no file is specified, enter
           the network namespace of the target process. If file is
           specified, enter the network namespace specified by file.

       -p, --pid[=file]
           Enter the PID namespace. If no file is specified, enter the
           PID namespace of the target process. If file is specified,
           enter the PID namespace specified by file.

       -U, --user[=file]
           Enter the user namespace. If no file is specified, enter the
           user namespace of the target process. If file is specified,
           enter the user namespace specified by file. See also the
           --setuid and --setgid options.

       --user-parent
           Enter the parent user namespace. Parent user namespace will
           be acquired from any other enabled namespace. If combined
           with --user option the parent user namespace will be fetched
           from the user namespace and replace it.

       -C, --cgroup[=file]
           Enter the cgroup namespace. If no file is specified, enter
           the cgroup namespace of the target process. If file is
           specified, enter the cgroup namespace specified by file.

       -T, --time[=file]
           Enter the time namespace. If no file is specified, enter the
           time namespace of the target process. If file is specified,
           enter the time namespace specified by file.

       -G, --setgid gid
           Set the group ID which will be used in the entered namespace
           and drop supplementary groups. nsenter always sets GID for
           user namespaces, the default is 0. If the argument "follow"
           is specified the GID of the target process is used.

       -S, --setuid uid
           Set the user ID which will be used in the entered namespace.
           nsenter always sets UID for user namespaces, the default is
           0. If the argument "follow" is specified the UID of the
           target process is used.

       --keep-caps
           When the --user option is given, ensure that capabilities
           granted in the user namespace are preserved in the child
           process.

       --preserve-credentials
           Don’t modify UID and GID when enter user namespace. The
           default is to drops supplementary groups and sets GID and UID
           to 0.

       -r, --root[=directory]
           Set the root directory. If no directory is specified, set the
           root directory to the root directory of the target process.
           If directory is specified, set the root directory to the
           specified directory. The specified directory is open before
           it switches to the requested namespaces.

       -w, --wd[=directory]
           Set the working directory. If no directory is specified, set
           the working directory to the working directory of the target
           process. If directory is specified, set the working directory
           to the specified directory. The specified directory is open
           before it switches to the requested namespaces, it means the
           specified directory works as "tunnel" to the current
           namespace. See also --wdns.

       -W, --wdns[=directory]
           Set the working directory. The directory is open after switch
           to the requested namespaces and after chroot(2) call. The
           options --wd and --wdns are mutually exclusive.

       -e, --env
           Pass environment variables from the target process to the new
           process being created. If this option is not provided, the
           environment variables will remain the same as in the current
           namespace..

       -F, --no-fork
           Do not fork before exec’ing the specified program. By
           default, when entering a PID namespace, nsenter calls fork
           before calling exec so that any children will also be in the
           newly entered PID namespace.

       -Z, --follow-context
           Set the SELinux security context used for executing a new
           process according to already running process specified by
           --target PID. (The util-linux has to be compiled with SELinux
           support otherwise the option is unavailable.)

       -c, --join-cgroup
           Add the initiated process to the cgroup of the target
           process.

       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

NOTES         top

       The --user-parent option requires Linux 4.9 or higher, older
       kernels will raise inappropriate ioctl for device error.

AUTHORS         top

       Eric Biederman <biederm@xmission.com>, Karel Zak
       <kzak@redhat.com>

SEE ALSO         top

       clone(2), setns(2), namespaces(7)

REPORTING BUGS         top

       For bug reports, use the issue tracker at
       https://github.com/util-linux/util-linux/issues.

AVAILABILITY         top

       The nsenter command is part of the util-linux package which can
       be downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>. This page
       is part of the util-linux (a random collection of Linux
       utilities) project. Information about the project can be found at
       ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you have
       a bug report for this manual page, send it to
       util-linux@vger.kernel.org. This page was obtained from the
       project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2023-12-22. (At that time, the date of the most recent commit
       that was found in the repository was 2023-12-14.) If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page,
       or you have corrections or improvements to the information in
       this COLOPHON (which is not part of the original manual page),
       send a mail to man-pages@man7.org

util-linux 2.39.594-1e0ad      2023-08-25                     NSENTER(1)

Pages that refer to this page: unshare(1)setns(2)ipc_namespaces(7)mount_namespaces(7)namespaces(7)network_namespaces(7)time_namespaces(7)uts_namespaces(7)lsns(8)