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<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<!DOCTYPE refentry PUBLIC @docdtd@ [
<!ENTITY commonoptions SYSTEM "@builddir@/common_options.sgml">
<!ENTITY seealso SYSTEM "@builddir@/see_also.sgml">
]>
<refentry>
<docinfo><date>@LXC_GENERATE_DATE@</date></docinfo>
<refmeta>
<refentrytitle>lxc-unshare</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>lxc-unshare</refname>
<refpurpose>
Run a task in a new set of namespaces.
</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>lxc-unshare</command>
<arg choice="req">-s, --namespaces <replaceable>namespaces</replaceable></arg>
<arg choice="opt">-u, --user <replaceable>user</replaceable></arg>
<arg choice="opt">-H, --hostname <replaceable>hostname</replaceable></arg>
<arg choice="opt">-i, --ifname <replaceable>ifname</replaceable></arg>
<arg choice="opt">-d, --daemon</arg>
<arg choice="opt">-M, --remount</arg>
<arg choice="req">command</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>lxc-unshare</command> 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.
</para>
</refsect1>
<refsect1>
<title>Options</title>
<variablelist>
<varlistentry>
<term>
<option>-s, --namespaces <replaceable>namespaces</replaceable></option>
</term>
<listitem>
<para>
Specify the namespaces to attach to, as a pipe-separated list,
e.g. <replaceable>NETWORK|IPC</replaceable>. Allowed values are
<replaceable>MOUNT</replaceable>, <replaceable>PID</replaceable>,
<replaceable>UTSNAME</replaceable>, <replaceable>IPC</replaceable>,
<replaceable>USER </replaceable> and
<replaceable>NETWORK</replaceable>. 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.
<replaceable>MOUNT\|PID</replaceable> or quoted, e.g.
<replaceable>"MOUNT|PID"</replaceable>.)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-u, --user <replaceable>user</replaceable></option>
</term>
<listitem>
<para>
Specify a userid which the new task should become.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-H, --hostname <replaceable>hostname</replaceable></option>
</term>
<listitem>
<para>
Set the hostname in the new container. Only allowed if
the UTSNAME namespace is set.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-i, --ifname <replaceable>interfacename</replaceable></option>
</term>
<listitem>
<para>
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
container.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-d, --daemon</option>
</term>
<listitem>
<para>
Daemonize (do not wait for the container to exit before exiting)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-M, --remount</option>
</term>
<listitem>
<para>
Mount default filesystems (/proc /dev/shm and /dev/mqueue)
in the container. Only allowed if MOUNT namespace is set.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
To spawn a new shell with its own UTS (hostname) namespace,
<programlisting>
lxc-unshare -s UTSNAME /bin/bash
</programlisting>
If the hostname is changed in that shell, the change will not be
reflected on the host.
</para>
<para>
To spawn a shell in a new network, pid, and mount namespace,
<programlisting>
lxc-unshare -s "NETWORK|PID|MOUNT" /bin/bash
</programlisting>
The resulting shell will have pid 1 and will see no network interfaces.
After re-mounting /proc in that shell,
<programlisting>
mount -t proc proc /proc
</programlisting>
ps output will show there are no other processes in the namespace.
</para>
<para>
To spawn a shell in a new network, pid, mount, and hostname
namespace.
<programlisting>
lxc-unshare -s "NETWORK|PID|MOUNT|UTSNAME" -M -H myhostname -i veth1 /bin/bash
</programlisting>
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.
</para>
</refsect1>
&seealso;
</refentry>
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