nsenter

NSENTER(1)                       User Commands                      NSENTER(1)

NAME
       nsenter - run program with namespaces of other processes

SYNOPSIS
       nsenter [options] [program [arguments]]

DESCRIPTION
       Enters  the namespaces of one or more other processes and then executes
       the specified program. 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_name-
              spaces(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 namespaces(7) and the discus-
              sion of the CLONE_NEWUTS flag in clone(2).

       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  namespaces(7)
              and the discussion of the CLONE_NEWIPC flag in clone(2).

       network namespace
              The process will have independent IPv4 and IPv6 stacks, IP rout-
              ing tables, firewall rules, the /proc/net and /sys/class/net di-
              rectory  trees,  sockets,  etc.   For further details, see name-
              spaces(7)  and  the  discussion  of  the  CLONE_NEWNET  flag  in
              clone(2).

       PID namespace
              Children  will  have  a  set of PID to process mappings separate
              from the nsenter process  For  further  details,  see  pid_name-
              spaces(7) and the discussion of the CLONE_NEWPID flag in 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  pro-
              gram will be exec'ed without forking.

       user namespace
              The process will have a distinct set of UIDs, GIDs and capabili-
              ties.  For further details, see user_namespaces(7) and the  dis-
              cussion of the CLONE_NEWUSER flag in clone(2).

       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) and the
              discussion of the CLONE_NEWCGROUP flag in clone(2).

       See clone(2) for the exact semantics of the flags.

OPTIONS
       Various of the options below that relate to namespaces take an optional
       file  argument.   This  should be one of the /proc/[pid]/ns/* files de-
       scribed in namespaces(7).

       -a, --all
              Enter all namespaces  of  the  target  process  by  the  default
              /proc/[pid]/ns/*  namespace paths. The default paths to the tar-
              get 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/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, en-
              ter the user namespace specified by file.  See also the --setuid
              and --setgid options.

       -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.

       -G, --setgid gid
              Set the group ID which will be used in the entered namespace and
              drop  supplementary groups.  nsenter(1) always sets GID for user
              namespaces, the default is 0.

       -S, --setuid uid
              Set the user ID which will be used  in  the  entered  namespace.
              nsenter(1)  always  sets UID for user namespaces, the default is
              0.

       --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.

       -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.

       -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 --tar-
              get PID. (The util-linux has to be compiled with SELinux support
              otherwise the option is unavailable.)

       -V, --version
              Display version information and exit.

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

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

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

AVAILABILITY
       The  nsenter command is part of the util-linux package and is available
       from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-
       linux/>.

util-linux                         June 2013                        NSENTER(1)