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authorSiri Hansen <[email protected]>2011-10-24 14:25:15 +0200
committerSiri Hansen <[email protected]>2011-11-17 16:47:29 +0100
commit281fb9929e2cdcfdaf95e0b90b3b690b78535ddb (patch)
tree2e296a38709a1fe03a9adc076e0e30ba3f25ea38 /system/doc/design_principles/release_handling.xml
parent1e344f34bf9f3fcc0a75b2980ab79e60d4cd71fc (diff)
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Document upgrade instructions restart_new_emulator and restart_emulator
Diffstat (limited to 'system/doc/design_principles/release_handling.xml')
-rw-r--r--system/doc/design_principles/release_handling.xml52
1 files changed, 44 insertions, 8 deletions
diff --git a/system/doc/design_principles/release_handling.xml b/system/doc/design_principles/release_handling.xml
index 1d62c242c0..8ed36f3c56 100644
--- a/system/doc/design_principles/release_handling.xml
+++ b/system/doc/design_principles/release_handling.xml
@@ -4,7 +4,7 @@
<chapter>
<header>
<copyright>
- <year>2003</year><year>2009</year>
+ <year>2003</year><year>2011</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
@@ -313,18 +313,35 @@
</section>
<section>
+ <marker id="restart_new_emulator_instr"></marker>
<title>restart_new_emulator (low-level)</title>
<p>This instruction is used when changing to a new emulator
- version, or if a system reboot is needed for some other reason.
- Requires that the system is started with heart beat
+ version, or when any of the core applications kernel, stdlib
+ or sasl is upgraded. If a system reboot is needed for some
+ other reason, the <c>restart_emulator</c> instruction should
+ be used instead.</p>
+ <p>Requires that the system is started with heart beat
monitoring, see <c>erl(1)</c> and <c>heart(3)</c>.</p>
- <p>When the release handler encounters the instruction, it shuts
- down the current emulator by calling <c>init:reboot()</c>, see
+ <p>The <c>restart_new_emulator</c> instruction shall always be
+ the very first instruction in a relup. If the relup is
+ generated by <c>systools:make_relup/3,4</c> this is
+ automatically ensured.</p>
+ <p>When the release handler encounters the instruction, it first
+ generates a temporary boot file, which starts the new versions
+ of the emulator and the core applications. Then it shuts down
+ the current emulator by calling <c>init:reboot()</c>, see
<c>init(3)</c>. All processes are terminated gracefully and
the system can then be rebooted by the heart program, using
- the new release version. This new version must still be made
- permanent when the new emulator is up and running. Otherwise,
- the old version is used in case of a new system reboot.</p>
+ the temporary boot file. After the reboot, the rest of the
+ relup instructions are executed. This is done as a part of the
+ boot script.</p>
+ <p>An info report is written when the upgrade is completed. To
+ programatically find out if the upgrade is complete,
+ call <c>release_handler:which_releases/0</c> and check if the
+ expected release has status <c>current</c>.</p>
+ <p>The new version must be made permanent when the new emulator
+ is up and running. Otherwise, the old version will be used in
+ case of a new system reboot.</p>
<p>On UNIX, the release handler tells the heart program which
command to use to reboot the system. Note that the environment
variable <c>HEART_COMMAND</c>, normally used by the heart
@@ -333,6 +350,25 @@
by using the SASL configuration parameter <c>start_prg</c>, see
<c>sasl(6)</c>.</p>
</section>
+
+ <section>
+ <marker id="restart_emulator_instr"></marker>
+ <title>restart_emulator (low-level)</title>
+ <p>This instruction is not related to upgrades of erts or any of
+ the core applications. It can be used by any application to
+ force a restart of the emulator after all upgrade instructions
+ are executed.</p>
+ <p>There can only be one <c>restart_emulator</c> instruction in
+ a relup script, and it shall always be placed at the end. If
+ the relup is generated by <c>systools:make_relup/3,4</c> this
+ is automatically ensured.</p>
+ <p>When the release handler encounters the instruction, it shuts down
+ the emulator by calling <c>init:reboot()</c>, see
+ <c>init(3)</c>. All processes are terminated gracefully and
+ the system can then be rebooted by the heart program using the
+ new release version. No more upgrade instruction will be
+ executed after the restart.</p>
+ </section>
</section>
<section>