Ubuntu Manpage: nsenter - run program with namespaces of other processes

Provided by: util-linux_2.27.1-6ubuntu3.10_amd64

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. Enterable namespaces are:

mount namespace
Mounting and unmounting filesystems will not affect the rest of the system (CLONE_
NEWNS flag), except for filesystems which are explicitly marked as shared (with
mount --make-shared; see /proc/self/mountinfo for the shared flag).

UTS namespace
Setting hostname or domainname will not affect the rest of the system. (CLONE_
NEWUTS flag)

IPC namespace
The process will have an independent namespace for System V message queues,
semaphore sets and shared memory segments. (CLONE_NEWIPC flag)

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. (CLONE_
NEWNET flag)

PID namespace
Children will have a set of PID to process mappings separate from the nsenter
process (CLONE_NEWPID flag). 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.

user namespace
The process will have a distinct set of UIDs, GIDs and capabilities. (CLONE_
NEWUSER flag)

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

If program is not given, then ``${SHELL}'' is run (default: /bin/sh).

OPTIONS

       -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/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.

       -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  --target  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.

AUTHORS

       Eric Biederman ⟨biederm@xmission.com⟩
       Karel Zak ⟨kzak@redhat.com⟩

AVAILABILITY