lxc-autostart: don't set timeout if user requested -s

[mirror_lxc.git] / doc / lxc-unshare.sgml.in

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lxc: linux Container library

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Authors:
Daniel Lezcano <daniel.lezcano at free.fr>
Serge Hallyn <serge.hallyn at ubuntu.com>

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<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 <replaceable>namespaces</replaceable></arg>
      <arg choice="req">-u <replaceable>user</replaceable></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 <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.
	  </para>
	</listitem>
      </varlistentry>

      <varlistentry>
	<term>
	  <option>-u <replaceable>user</replaceable></option>
	</term>
	<listitem>
	  <para>
	    Specify a user which the new task should become.  This option is
	    only valid if a user namespace is unshared.
	  </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>
  </refsect1>

  &seealso;

  <refsect1>
    <title>Author</title>
    <para>Daniel Lezcano <email>daniel.lezcano@free.fr</email></para>
  </refsect1>

</refentry>

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