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(4). 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(4), appup(4), rel(4), release_handler(3),
systools(3)