relup(4)
NAME
relup - Release upgrade file
DESCRIPTION
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.
FILE SYNTAX
In a target system, the release upgrade file should be located in the OTP_ROOT/erts-EVsn/Vsn directory.
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() is the current version of the release.
- * UpFromVsn = string() is an earlier version of the release to
upgrade from.
- * Descr = term() is a user defined parameter passed from the sys
tools:make_relup/3, 4 function. It will be used in the return value of release_handler:install_release/1, 2.
- * Instructions is 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() is an earlier version of the release to down
grade to.
- When upgrading from UpFromVsn with release_handler:install_release/1, 2, there does not have to be an exact match of versions, but UpFromVsn can be a sub-string of the current release version.