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@@ -173,4 +173,60 @@ EOF</userinput></screen>
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</itemizedlist>
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</sect2>
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+
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+ <sect2>
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+ <title>Long Running Processes</title>
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+
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+ <para>Beginning with systemd-230, all user processes are killed when a
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+ user session is ended, even if nohup is used, or the process uses
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+ <function>daemon()</function> or <function>setsid()</function>. This is a
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+ deliberate change from a historically permissive environment to a more
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+ restrictive one. The new behavior may cause issues if you depend on long
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+ running programs (e.g., <command>screen</command> or
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+ <command>tmux</command>) to remain active after ending your user
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+ session. There are three ways to enable lingering processes to remain after
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+ a user session is ended.</para>
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+
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+ <itemizedlist>
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+ <listitem>
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+ <para>
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+ <emphasis>Enable process lingering for only needed users</emphasis>:
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+ normal users have permission to enabling process lingering
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+ with the command <command>loginctl enable-linger</command> for their
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+ own user. System administrators can use the same command with a
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+ <parameter>user</parameter> argument to enable for a user. That user
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+ can then use the <command>systemd-run</command> command to start
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+ long running processes. For example: <command>systemd-run --scope
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+ --user /usr/bin/screen</command>. If you enable lingering for your
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+ user, the user@.service will remain even after all login sessions are
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+ closed, and will automatically start at system boot. This has the
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+ advantage of explicitly allowing and disallowing processes to run
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+ after the user session has ended, but breaks backwards compatibility
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+ with tools like <command>nohup</command> and utilities that use
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+ <function>deamon()</function>.
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>Enable system-wide process lingering</emphasis>:
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+ you can set <parameter>KillUserProcesses=no</parameter> in
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+ <filename>/etc/logind.conf</filename> to enable process lingering
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+ globally for all users. This has the benefit of leaving the old
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+ method available to all users at the expense of explicit control.
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+ </para>
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+ </listitem>
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+ <listitem>
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+ <para>
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+ <emphasis>Disable at build-time</emphasis>: You can enable
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+ lingering by default while building systemd by adding the switch
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+ <parameter>--without-kill-user-processes</parameter> to the
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+ <command>configure</command> command for systemd. This completely
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+ disables the ability of systemd to kill user processes at session
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+ end.
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+ </para>
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+ </listitem>
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+ </itemizedlist>
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+
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+ </sect2>
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+
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</sect1>
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DJ Lucas