NSENTER(1) User Commands NSENTER(1)
NAME
nsenter - run program in different namespaces
SYNOPSIS
nsenter [options] [program [arguments]]
DESCRIPTION
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
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.
-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.
-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.
--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.
-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.)
-h, --help
Display help text and exit.
-V, --version
Print version and exit.
AUTHORS
Eric Biederman <biederm@xmission.com>, Karel Zak <kzak@redhat.com>
SEE ALSO
clone(2), setns(2), namespaces(7)
REPORTING BUGS
For bug reports, use the issue tracker at
https://github.com/util-linux/util-linux/issues.
AVAILABILITY
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/>.
util-linux 2.38.1 2022-05-11 NSENTER(1)
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