lxc-unshare(1) — Linux manual page


lxc-unshare(1)                                            lxc-unshare(1)

NAME         top

       lxc-unshare - Run a task in a new set of namespaces.

SYNOPSIS         top

       lxc-unshare {-s, --namespaces namespaces} [-u, --user user] [-H,
                   --hostname hostname] [-i, --ifname ifname] [-d,
                   --daemon] [-M, --remount] {command}

DESCRIPTION         top

       lxc-unshare can be used to run a task in a cloned set of
       namespaces. This command is mainly provided for testing purposes.
       Despite its name, it always uses clone rather than unshare to
       create the new task with fresh namespaces. Apart from testing
       kernel regressions this should make no difference.

OPTIONS         top

       -s, --namespaces namespaces
              Specify the namespaces to attach to, as a pipe-separated
              list, e.g. NETWORK|IPC. Allowed values are MOUNT, PID,
              UTSNAME, IPC, USER and NETWORK. This allows one to change
              the context of the process to e.g. the network namespace
              of the container while retaining the other namespaces as
              those of the host. (The pipe symbol needs to be escaped,
              e.g.  MOUNT\|PID or quoted, e.g.  "MOUNT|PID".)

       -u, --user user
              Specify a userid which the new task should become.

       -H, --hostname hostname
              Set the hostname in the new container. Only allowed if the
              UTSNAME namespace is set.

       -i, --ifname interfacename
              Move the named interface into the container. Only allowed
              if the NETWORK namespace is set. You may specify this
              argument multiple times to move multiple interfaces into

       -d, --daemon
              Daemonize (do not wait for the container to exit before

       -M, --remount
              Mount default filesystems (/proc /dev/shm and /dev/mqueue)
              in the container. Only allowed if MOUNT namespace is set.

EXAMPLES         top

       To spawn a new shell with its own UTS (hostname) namespace,

                 lxc-unshare -s UTSNAME /bin/bash

       If the hostname is changed in that shell, the change will not be
       reflected on the host.

       To spawn a shell in a new network, pid, and mount namespace,

                 lxc-unshare -s "NETWORK|PID|MOUNT" /bin/bash

       The resulting shell will have pid 1 and will see no network
       interfaces.  After re-mounting /proc in that shell,

                 mount -t proc proc /proc

       ps output will show there are no other processes in the

       To spawn a shell in a new network, pid, mount, and hostname

                 lxc-unshare -s "NETWORK|PID|MOUNT|UTSNAME" -M -H myhostname -i veth1 /bin/bash

       The resulting shell will have pid 1 and will see two network
       interfaces (lo and veth1). The hostname will be "myhostname" and
       /proc will have been remounted. ps output will show there are no
       other processes in the namespace.

SEE ALSO         top

       lxc(7), lxc-create(1), lxc-copy(1), lxc-destroy(1), lxc-start(1),
       lxc-stop(1), lxc-execute(1), lxc-console(1), lxc-monitor(1),
       lxc-wait(1), lxc-cgroup(1), lxc-ls(1), lxc-info(1),
       lxc-freeze(1), lxc-unfreeze(1), lxc-attach(1), lxc.conf(5)

AUTHOR         top

       Daniel Lezcano <daniel.lezcano@free.fr>

COLOPHON         top

       This page is part of the lxc (Linux containers) project.
       Information about the project can be found at 
       ⟨http://linuxcontainers.org/⟩.  If you have a bug report for this
       manual page, send it to lxc-devel@lists.linuxcontainers.org.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/lxc/lxc.git⟩ on 2023-12-22.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2023-12-18.)  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

                               2022-06-16                 lxc-unshare(1)