<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE fileref SYSTEM "fileref.dtd">
<fileref>
<header>
<copyright>
<year>1997</year>
<year>2016</year>
<holder>Ericsson AB, All Rights Reserved</holder>
</copyright>
<legalnotice>
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
The Initial Developer of the Original Code is Ericsson AB.
</legalnotice>
<title>relup</title>
<prepared></prepared>
<docno></docno>
<date></date>
<rev></rev>
</header>
<file>relup</file>
<filesummary>Release upgrade file</filesummary>
<description>
<p>The <em>release upgrade file</em> describes how a release is
upgraded in a running system.</p>
<p>This file is automatically generated by
<seealso marker="systools#make_relup/3"><c>systools:make_relup/3,4</c></seealso>,
using a release resource file
(<c>.rel</c>), application resource files (<c>.app</c>), and
application upgrade files (<c>.appup</c>) as input.</p>
</description>
<section>
<title>File Syntax</title>
<p>In a target system, the release upgrade file is to be located in
directory <c>$ROOT/releases/Vsn</c>.</p>
<p>The <c>relup</c> file contains one single Erlang term, which
defines the instructions used to upgrade the release. The file has
the following syntax:</p>
<code type="none">
{Vsn,
[{UpFromVsn, Descr, Instructions}, ...],
[{DownToVsn, Descr, Instructions}, ...]}.</code>
<taglist>
<tag><c>Vsn = string()</c></tag>
<item><p>Current release version.</p></item>
<tag><c>UpFromVsn = string()</c></tag>
<item><p>Earlier version of the release to upgrade from.</p></item>
<tag><c>Descr = term()</c></tag>
<item><p>A user-defined parameter passed
from the function
<seealso marker="systools#make_relup/3"><c>systools:make_relup/3,4</c></seealso>.
It is used in the return value of
<seealso marker="release_handler#install_release/1"><c>release_handler:install_release/1,2</c></seealso>.</p></item>
<tag><c>Instructions</c></tag>
<item><p>A list of low-level release upgrade instructions, see
<seealso marker="appup"><c>appup(4)</c></seealso>.
It consists of the release upgrade instructions from
the respective application upgrade files (high-level instructions
are translated to low-level instructions), in the same order
as in the start script.</p></item>
<tag><c>DownToVsn = string()</c></tag>
<item><p>Earlier version of the release to downgrade to.</p></item>
</taglist>
</section>
<section>
<title>See Also</title>
<p><seealso marker="kernel:app"><c>app(4)</c></seealso>,
<seealso marker="appup"><c>appup(4)</c></seealso>,
<seealso marker="rel"><c>rel(4)</c></seealso>,
<seealso marker="release_handler"><c>release_handler(3)</c></seealso>,
<seealso marker="systools"><c>systools(3)</c></seealso></p>
</section>
</fileref>
