relup - Release upgrade file
The
release upgrade file describes how a release is upgraded in a running
system.
This file is automatically generated by
systools:make_relup/3,4, using a
release resource file (
.rel), application resource files
(
.app), and application upgrade files (
.appup) as input.
In a target system, the release upgrade file is to be located in directory
$ROOT/releases/Vsn.
The
relup file contains one single Erlang term, which defines the
instructions used to upgrade the release. The file has the following syntax:
{Vsn,
[{UpFromVsn, Descr, Instructions}, ...],
[{DownToVsn, Descr, Instructions}, ...]}.
- Vsn = string():
- Current release version.
- UpFromVsn = string():
- Earlier version of the release to upgrade from.
- Descr = term():
- A user-defined parameter passed from the function
systools:make_relup/3,4. It is used in the return value of
release_handler:install_release/1,2.
- Instructions:
- A list of low-level release upgrade instructions, see
appup(5). 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.
- DownToVsn = string():
- Earlier version of the release to downgrade to.
app(5),
appup(5),
rel(5),
release_handler(3erl),
systools(3erl)