UNSHARE(1) User Commands UNSHARE(1)NAME
unshare - run program with some namespaces unshared from parent
SYNOPSIS
unshare [options] program [arguments]
DESCRIPTION
Unshares the indicated namespaces from the parent process and then exe‐
cutes the specified program. The namespaces to be unshared are indi‐
cated via options. Unshareable 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 flags).
It's recommended to use mount --make-rprivate or mount --make-
rslave after unshare --mount to make sure that mountpoints in
the new namespace are really unshared from parental namespace.
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 mes‐
sage queues, semaphore sets and shared memory segments.
(CLONE_NEWIPC flag)
network namespace
The process will have independent IPv4 and IPv6 stacks, IP rout‐
ing tables, firewall rules, the /proc/net and /sys/class/net
directory trees, sockets, etc. (CLONE_NEWNET flag)
pid namespace
Children will have a distinct set of PID to process mappings
from their parent. (CLONE_NEWPID flag)
user namespace
The process will have a distinct set of UIDs, GIDs and capabili‐
ties. (CLONE_NEWUSER flag)
See clone(2) for the exact semantics of the flags.
OPTIONS-h, --help
Display help text and exit.
-i, --ipc
Unshare the IPC namespace.
-m, --mount
Unshare the mount namespace.
-n, --net
Unshare the network namespace.
-p, --pid
Unshare the pid namespace. See also the --fork and --mount-proc
options.
-u, --uts
Unshare the UTS namespace.
-U, --user
Unshare the user namespace.
-f, --fork
Fork the specified program as a child process of unshare rather
than running it directly. This is useful when creating a new
pid namespace.
--mount-proc[=mountpoint]
Just before running the program, mount the proc filesystem at
the mountpoint (default is /proc). This is useful when creating
a new pid namespace. It also implies creating a new mount
namespace since the /proc mount would otherwise mess up existing
programs on the system. The new proc filesystem is explicitly
mounted as private (by MS_PRIVATE|MS_REC).
SEE ALSOunshare(2), clone(2), mount(8)BUGS
None known so far.
AUTHOR
Mikhail Gusarov <dottedmag@dottedmag.net>
AVAILABILITY
The unshare command is part of the util-linux package and is available
from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.
util-linux July 2013 UNSHARE(1)
