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diff --git a/lib/sasl/doc/src/release_handler.xml b/lib/sasl/doc/src/release_handler.xml new file mode 100644 index 0000000000..4a973bc5ed --- /dev/null +++ b/lib/sasl/doc/src/release_handler.xml @@ -0,0 +1,697 @@ +<?xml version="1.0" encoding="latin1" ?> +<!DOCTYPE erlref SYSTEM "erlref.dtd"> + +<erlref> + <header> + <copyright> + <year>1996</year><year>2009</year> + <holder>Ericsson AB. All Rights Reserved.</holder> + </copyright> + <legalnotice> + The contents of this file are subject to the Erlang Public License, + Version 1.1, (the "License"); you may not use this file except in + compliance with the License. You should have received a copy of the + Erlang Public License along with this software. If not, it can be + retrieved online at http://www.erlang.org/. + + Software distributed under the License is distributed on an "AS IS" + basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See + the License for the specific language governing rights and limitations + under the License. + + </legalnotice> + + <title>release_handler</title> + <prepared></prepared> + <docno></docno> + <date></date> + <rev></rev> + </header> + <module>release_handler</module> + <modulesummary>Unpacking and Installation of Release Packages</modulesummary> + <description> + <p>The <em>release handler</em> is a process belonging to the SASL + application which is responsible for <em>release handling</em>, + that is, unpacking, installation, and removal of release packages.</p> + <p>An introduction to release handling and a usage example can be + found in + <seealso marker="doc/design_principles:release_handling">Design Principles</seealso>. + </p> + <p>A <em>release package</em> is a compressed tar file containing + code for a certain version of a release, created by calling + <seealso marker="systools#make_tar/1">systools:make_tar/1,2</seealso>. + The release package should be placed in the <c>$ROOT/releases</c> + directory of the previous version of the release where + <c>$ROOT</c> is the installation root directory, + <c>code:root_dir()</c>. + Another <c>releases</c> directory can be specified using the SASL + configuration parameter <c>releases_dir</c>, or the OS environment + variable <c>RELDIR</c>. The release handler must have write access + to this directory in order to install the new release. + The persistent state of the release handler is stored there in a + file called <c>RELEASES</c>.</p> + <p>A release package should always contain the release resource file + <c>Name.rel</c> and a boot script <c>Name.boot</c>. It may contain + a release upgrade file <c>relup</c> and a system configuration + file <c>sys.config</c>. The <c>.rel</c> file contains information + about the release: its name, version, and which ERTS and + application versions it uses. The <c>relup</c> file contains + scripts for how to upgrade to, or downgrade from, this version of + the release.</p> + <p>The release package can be <em>unpacked</em>, which extracts + the files. An unpacked release can be <em>installed</em>. + The currently used version of the release is then upgraded or + downgraded to the specified version by evaluating the instructions + in <c>relup</c>. An installed release can be made + <em>permanent</em>. There can only be one permanent release in + the system, and this is the release that is used if the system is + restarted. An installed release, except the permanent one, can be + <em>removed</em>. When a release is removed, all files that + belong to that release only are deleted.</p> + <p>Each version of the release has a status. The status can be + <c>unpacked</c>, <c>current</c>, <c>permanent</c>, or <c>old</c>. + There is always one latest release which either has status + <c>permanent</c> (normal case), or <c>current</c> (installed, but + not yet made permanent). The following table illustrates + the meaning of the status values:</p> + <pre> +Status Action NextStatus +------------------------------------------- + - unpack unpacked +unpacked install current + remove - +current make_permanent permanent + install other old + remove - +permanent make other permanent old + install permanent +old reboot_old permanent + install current + remove - + </pre> + <p>The release handler process is a locally registered process on + each node. When a release is installed in a distributed system, + the release handler on each node must be called. The release + installation may be synchronized between nodes. From an operator + view, it may be unsatisfactory to specify each node. The aim is + to install one release package in the system, no matter how many + nodes there are. If this is the case, it is recommended that + software management functions are written which take care of + this problem. Such a function may have knowledge of the system + architecture, so it can contact each individual release handler + to install the package.</p> + <p>For release handling to work properly, the runtime system needs + to have knowledge about which release it is currently running. It + must also be able to change (in run-time) which boot script and + system configuration file should be used if the system is + restarted. This is taken care of automatically if Erlang is + started as an embedded system. Read about this in <em>Embedded System</em>. In this case, the system configuration file + <c>sys.config</c> is mandatory.</p> + <p>A new release may restart the system. Which program to use is + specified by the SASL configuration parameter <c>start_prg</c> + which defaults to <c>$ROOT/bin/start</c>.</p> + <p>The emulator restart on Windows NT expects that the system is + started using the <c>erlsrv</c> program (as a service). + Furthermore the release handler expects that the service is named + <em>NodeName</em>_<em>Release</em>, where <em>NodeName</em> is + the first part of the Erlang nodename (up to, but not including + the "@") and <em>Release</em> is the current release of + the application. The release handler furthermore expects that a + program like <c>start_erl.exe</c> is specified as "machine" to + <c>erlsrv</c>. During upgrading with restart, a new service will + be registered and started. The new service will be set to + automatic and the old service removed as soon as the new release + is made permanent.</p> + <p>The release handler at a node which runs on a diskless machine, + or with a read-only file system, must be configured accordingly + using the following <c>sasl</c> configuration parameters (see + <seealso marker="sasl_app">sasl(6)</seealso> for details):</p> + <taglist> + <tag><c>masters</c></tag> + <item> + <p>This node uses a number of master nodes in order to store + and fetch release information. All master nodes must be up + and running whenever release information is written by this + node.</p> + </item> + <tag><c>client_directory</c></tag> + <item> + <p>The <c>client_directory</c> in the directory structure of + the master nodes must be specified.</p> + </item> + <tag><c>static_emulator</c></tag> + <item> + <p>This parameter specifies if the Erlang emulator is + statically installed at the client node. A node with a static + emulator cannot dynamically switch to a new emulator because + the executable files are statically written into memory.</p> + </item> + </taglist> + <p>It is also possible to use the release handler to unpack and + install release packages when not running Erlang as an embedded + system, but in this case the user must somehow make sure that + correct boot scripts and configuration files are used if + the system needs to be restarted.</p> + <p>There are additional functions for using another file structure + than the structure defined in OTP. These functions can be used + to test a release upgrade locally.</p> + </description> + <funcs> + <func> + <name>check_install_release(Vsn) -> {ok, OtherVsn, Descr} | {error, Reason}</name> + <fsummary>Check installation of a release in the system.</fsummary> + <type> + <v>Vsn = OtherVsn = string()</v> + <v>Descr = term()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Checks if the specified version <c>Vsn</c> of the release + can be installed. The release must not have status + <c>current</c>. Issues warnings if <c>relup</c> or + <c>sys.config</c> are not present. If <c>relup</c> is present, + its contents are checked and <c>{error,Reason}</c> is + returned if an error is found. Also checks that all required + applications are present and that all new code can be loaded, + or <c>{error,Reason}</c> is returned.</p> + <p>This function evaluates all instructions that occur before + the <c>point_of_no_return</c> instruction in the release + upgrade script.</p> + <p>Returns the same as <c>install_release/1</c>. <c>Descr</c> + defaults to "" if no <c>relup</c> file is found.</p> + </desc> + </func> + <func> + <name>create_RELEASES(Root, RelDir, RelFile, AppDirs) -> ok | {error, Reason}</name> + <fsummary>Create an initial RELEASES file.</fsummary> + <type> + <v>Root = RelDir = RelFile = string()</v> + <v>AppDirs = [{App, Vsn, Dir}]</v> + <v> App = atom()</v> + <v> Vsn = Dir = string()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Creates an initial RELEASES file to be used by the release + handler. This file must exist in order to install new + releases.</p> + <p><c>Root</c> is the root of the installation (<c>$ROOT</c>) as + described above. <c>RelDir</c> is the the directory where + the <c>RELEASES</c> file should be created (normally + <c>$ROOT/releases</c>). <c>RelFile</c> is the name + of the <c>.rel</c> file that describes the initial release, + including the extension <c>.rel</c>.</p> + <p><c>AppDirs</c> can be used to specify from where the modules + for the specified applications should be loaded. <c>App</c> is + the name of an application, <c>Vsn</c> is the version, and + <c>Dir</c> is the name of the directory where <c>App-Vsn</c> + is located. The corresponding modules should be located under + <c>Dir/App-Vsn/ebin</c>. The directories for applications not + specified in <c>AppDirs</c> are assumed to be located in + <c>$ROOT/lib</c>.</p> + </desc> + </func> + <func> + <name>install_file(Vsn, File) -> ok | {error, Reason}</name> + <fsummary>Install a release file in the release structure.</fsummary> + <type> + <v>Vsn = File = string()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Installs a release dependent file in the release structure. + A release dependent file is a file that must be in + the release structure when a new release is installed: + <c>start.boot</c>, <c>relup</c> and <c>sys.config</c>.</p> + <p>The function can be called, for example, when these files + are generated at the target. It should be called after + <c>set_unpacked/2</c> has been called.</p> + </desc> + </func> + <func> + <name>install_release(Vsn) -> {ok, OtherVsn, Descr} | {error, Reason}</name> + <name>install_release(Vsn, [Opt]) -> {ok, OtherVsn, Descr} | {error, Reason}</name> + <fsummary>Install a release in the system.</fsummary> + <type> + <v>Vsn = OtherVsn = string()</v> + <v>Opt = {error_action, Action} | {code_change_timeout, Timeout}</v> + <v> | {suspend_timeout, Timeout} | {update_paths, Bool}</v> + <v> Action = restart | reboot</v> + <v> Timeout = default | infinity | int()>0</v> + <v> Bool = boolean()</v> + <v>Descr = term()</v> + <v>Reason = {illegal_option, Opt} | {already_installed, Vsn} | {change_appl_data, term()} | term()</v> + </type> + <desc> + <p>Installs the specified version <c>Vsn</c> of the release. + Looks first for a <c>relup</c> file for <c>Vsn</c> and a + script <c>{UpFromVsn,Descr1,Instructions1}</c> in this file + for upgrading from the current version. If not found, + the function looks for a <c>relup</c> file for the current + version and a script <c>{Vsn,Descr2,Instructions2}</c> in this + file for downgrading to <c>Vsn</c>.</p> + <p>If a script is found, the first thing that happens is that + the applications specifications are updated according to + the <c>.app</c> files and <c>sys.config</c> belonging to + the release version <c>Vsn</c>.</p> + <p>After the application specifications have been updated, + the instructions in the script are evaluated and the function + returns <c>{ok,OtherVsn,Descr}</c> if successful. + <c>OtherVsn</c> and <c>Descr</c> are the version + (<c>UpFromVsn</c> or <c>Vsn</c>) and description + (<c>Descr1</c> or <c>Descr2</c>) as specified in the script.</p> + <p>If a recoverable error occurs, the function returns + <c>{error,Reason}</c> and the original application + specifications are restored. If a non-recoverable error + occurs, the system is restarted.</p> + <p>The option <c>error_action</c> defines if the node should be + restarted (<c>init:restart()</c>) or rebooted + (<c>init:reboot()</c>) in case of an error during + the installation. Default is <c>restart</c>.</p> + <p>The option <c>code_change_timeout</c> defines the timeout + for all calls to <c>sys:change_code</c>. If no value is + specified or <c>default</c> is given, the default value + defined in <c>sys</c> is used.</p> + <p>The option <c>suspend_timeout</c> defines the timeout for + all calls to <c>sys:suspend</c>. If no value is specified, + the values defined by the <c>Timeout</c> parameter of + the <c>upgrade</c> or <c>suspend</c> instructions are used. + If <c>default</c> is specified, the default value defined in + <c>sys</c> is used.</p> + <p>The option <c>{update_paths,Bool}</c> indicates if all + application code paths should be updated (<c>Bool==true</c>), + or if only code paths for modified applications should be + updated (<c>Bool==false</c>, default). This option only has + effect for other application directories than the default + <c>$ROOT/lib/App-Vsn</c>, that is, application directories + provided in the <c>AppDirs</c> argument in a call to + <c>create_RELEASES/4</c> or <c>set_unpacked/2</c>.</p> + <p>Example: In the current version <c>CurVsn</c> of a release, + the application directory of <c>myapp</c> is + <c>$ROOT/lib/myapp-1.0</c>. A new version <c>NewVsn</c> is + unpacked outside the release handler, and the release handler + is informed about this with a call to:</p> + <code type="none"> +release_handler:set_unpacked(RelFile, [{myapp,"1.0","/home/user"},...]). +=> {ok,NewVsn} + </code> + <p>If <c>NewVsn</c> is installed with the option + <c>{update_paths,true}</c>, afterwards + <c>code:lib_dir(myapp)</c> will return + <c>/home/user/myapp-1.0</c>.</p> + </desc> + </func> + <func> + <name>make_permanent(Vsn) -> ok | {error, Reason}</name> + <fsummary>Make the specified release version permanent.</fsummary> + <type> + <v>Vsn = string()</v> + <v>Reason = {bad_status, Status} | term()</v> + </type> + <desc> + <p>Makes the specified version <c>Vsn</c> of the release + permanent.</p> + </desc> + </func> + <func> + <name>remove_release(Vsn) -> ok | {error, Reason}</name> + <fsummary>Remove a release from the system.</fsummary> + <type> + <v>Vsn = string()</v> + <v>Reason = {permanent, Vsn} | client_node | term()</v> + </type> + <desc> + <p>Removes a release and its files from the system. + The release must not be the permanent release. Removes only + the files and directories not in use by another release.</p> + </desc> + </func> + <func> + <name>reboot_old_release(Vsn) -> ok | {error, Reason}</name> + <fsummary>Reboot the system from an old release.</fsummary> + <type> + <v>Vsn = string()</v> + <v>Reason = {bad_status, Status} | term()</v> + </type> + <desc> + <p>Reboots the system by making the old release permanent, and + calls <c>init:reboot()</c> directly. The release must have + status <c>old</c>.</p> + </desc> + </func> + <func> + <name>set_removed(Vsn) -> ok | {error, Reason}</name> + <fsummary>Mark a release as removed.</fsummary> + <type> + <v>Vsn = string()</v> + <v>Reason = {permanent, Vsn} | term()</v> + </type> + <desc> + <p>Makes it possible to handle removal of releases outside + the release handler. Tells the release handler that + the release is removed from the system. This function does + not delete any files.</p> + </desc> + </func> + <func> + <name>set_unpacked(RelFile, AppDirs) -> {ok, Vsn} | {error, Reason}</name> + <fsummary>Mark a release as unpacked.</fsummary> + <type> + <v>RelFile = string()</v> + <v>AppDirs = [{App, Vsn, Dir}]</v> + <v> App = atom()</v> + <v> Vsn = Dir = string()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Makes it possible to handle unpacking of releases outside + the release handler. Tells the release handler that + the release is unpacked. <c>Vsn</c> is extracted from + the release resource file <c>RelFile</c>.</p> + <p><c>AppDirs</c> can be used to specify from where the modules + for the specified applications should be loaded. <c>App</c> is + the name of an application, <c>Vsn</c> is the version, and + <c>Dir</c> is the name of the directory where <c>App-Vsn</c> + is located. The corresponding modules should be located under + <c>Dir/App-Vsn/ebin</c>. The directories for applications not + specified in <c>AppDirs</c> are assumed to be located in + <c>$ROOT/lib</c>.</p> + </desc> + </func> + <func> + <name>unpack_release(Name) -> {ok, Vsn} | {error, Reason}</name> + <fsummary>Unpack a release package.</fsummary> + <type> + <v>Name = Vsn = string()</v> + <v>Reason = client_node | term()</v> + </type> + <desc> + <p>Unpacks a release package <c>Name.tar.gz</c> located in + the <c>releases</c> directory.</p> + <p>Performs some checks on the package - for example checks + that all mandatory files are present - and extracts its + contents.</p> + </desc> + </func> + <func> + <name>which_releases() -> [{Name, Vsn, Apps, Status}]</name> + <fsummary>Return all known releases</fsummary> + <type> + <v>Name = Vsn = string()</v> + <v>Apps = ["App-Vsn"]</v> + <v>Status = unpacked | current | permanent | old</v> + </type> + <desc> + <p>Returns all releases known to the release handler.</p> + </desc> + </func> + </funcs> + + <section> + <title>Application Upgrade/Downgrade</title> + <p>The following functions can be used to test upgrade and downgrade + of single applications (instead of upgrading/downgrading an entire + release). A script corresponding to <c>relup</c> is created + on-the-fly, based on the <c>.appup</c> file for the application, + and evaluated exactly in the same way as <c>release_handler</c> + does.</p> + <warning> + <p>These function is primarily intended for simplified testing of + of <c>.appup</c> files. They are not run within the context of + the <c>release_handler</c> process. They must therefore + <em>not</em> be used together with calls to + <c>install_release/1,2</c>, as this will cause + <c>release_handler</c> to end up in an inconsistent state.</p> + <p>No persistent information is updated, why these functions can + be used on any Erlang node, embedded or not. Also, using these + functions does not effect which code will be loaded in case of + a reboot.</p> + <p>If the upgrade or downgrade fails, the application may end up + in an inconsistent state.</p> + </warning> + </section> + <funcs> + <func> + <name>upgrade_app(App, Dir) -> {ok, Unpurged} | restart_new_emulator | {error, Reason}</name> + <fsummary>Upgrade to a new application version</fsummary> + <type> + <v>App = atom()</v> + <v>Dir = string()</v> + <v>Unpurged = [Module]</v> + <v> Module = atom()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Upgrades an application <c>App</c> from the current + version to a new version located in <c>Dir</c> according to + the <c>.appup</c> script.</p> + <p><c>App</c> is the name of the application, which must be + started. <c>Dir</c> is the new library directory of + <c>App</c>, the corresponding modules as well as + the <c>.app</c> and <c>.appup</c> files should be located + under <c>Dir/ebin</c>.</p> + <p>The function looks in the <c>.appup</c> file and tries to + find an upgrade script from the current version of + the application using + <seealso marker="#upgrade_script/2">upgrade_script/2</seealso>. + This script is evaluated using + <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>, + exactly in the same way as + <seealso marker="#install_release/1">install_release/1,2</seealso> + does.</p> + <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is + successful, where <c>Unpurged</c> is a list of unpurged + modules, or <c>restart_new_emulator</c> if this instruction is + encountered in the script, or <c>{error, Reason}</c> if + an error occurred when finding or evaluating the script.</p> + </desc> + </func> + <func> + <name>downgrade_app(App, Dir) -></name> + <name>downgrade_app(App, OldVsn, Dir) -> {ok, Unpurged} | restart_new_emulator | {error, Reason}</name> + <fsummary>Downgrade to a previous application version</fsummary> + <type> + <v>App = atom()</v> + <v>Dir = OldVsn = string()</v> + <v>Unpurged = [Module]</v> + <v> Module = atom()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Downgrades an application <c>App</c> from the current + version to a previous version <c>OldVsn</c> located in + <c>Dir</c> according to the <c>.appup</c> script.</p> + <p><c>App</c> is the name of the application, which must be + started. <c>OldVsn</c> is the previous version of + the application and can be omitted if <c>Dir</c> is of + the format <c>"App-OldVsn"</c>. <c>Dir</c> is the library + directory of this previous version of <c>App</c>, + the corresponding modules as well as the old <c>.app</c> file + should be located under <c>Dir/ebin</c>. The <c>.appup</c> + file should be located in the <c>ebin</c> directory of + the <em>current</em> library directory of the application + (<c>code:lib_dir(App)</c>).</p> + <p>The function looks in the <c>.appup</c> file and tries to + find an downgrade script to the previous version of + the application using + <seealso marker="#downgrade_script/3">downgrade_script/3</seealso>. + This script is evaluated using + <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>, + exactly in the same way as + <seealso marker="#install_release/1">install_release/1,2</seealso> + does.</p> + <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is + successful, where <c>Unpurged</c> is a list of unpurged + modules, or <c>restart_new_emulator</c> if this instruction is + encountered in the script, or <c>{error, Reason}</c> if + an error occurred when finding or evaluating the script.</p> + </desc> + </func> + <func> + <name>upgrade_script(App, Dir) -> {ok, NewVsn, Script}</name> + <fsummary>Find an application upgrade script</fsummary> + <type> + <v>App = atom()</v> + <v>Dir = string()</v> + <v>NewVsn = string()</v> + <v>Script = Instructions -- see appup(4)</v> + </type> + <desc> + <p>Tries to find an application upgrade script for <c>App</c> + from the current version to a new version located in + <c>Dir</c>.</p> + <p>The upgrade script can then be evaluated using + <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>. + It is recommended to use + <seealso marker="#upgrade_app/2">upgrade_app/2</seealso> + instead, but this function is useful in order to inspect + the contents of the script.</p> + <p><c>App</c> is the name of the application, which must be + started. <c>Dir</c> is the new library directory of + <c>App</c>, the corresponding modules as well as + the <c>.app</c> and <c>.appup</c> files should be located + under <c>Dir/ebin</c>.</p> + <p>The function looks in the <c>.appup</c> file and tries to + find an upgrade script from the current version of + the application. High-level instructions are translated to + low-level instructions and the instructions are sorted in + the same manner as when generating a <c>relup</c> script.</p> + <p>Returns <c>{ok, NewVsn, Script}</c> if successful, where + <c>NewVsn</c> is the new application version.</p> + <p>Failure: If a script cannot be found, the function fails + with an appropriate error reason.</p> + </desc> + </func> + <func> + <name>downgrade_script(App, OldVsn, Dir) -> {ok, Script}</name> + <fsummary>Find an application downgrade script</fsummary> + <type> + <v>App = atom()</v> + <v>OldVsn = Dir = string()</v> + <v>Script = Instructions -- see appup(4)</v> + </type> + <desc> + <p>Tries to find an application downgrade script for <c>App</c> + from the current version to a previous version <c>OldVsn</c> + located in <c>Dir</c>.</p> + <p>The downgrade script can then be evaluated using + <seealso marker="#eval_appup_script/4">eval_appup_script/4</seealso>. + It is recommended to use + <seealso marker="#downgrade_app/2">downgrade_app/2,3</seealso> + instead, but this function is useful in order to inspect + the contents of the script.</p> + <p><c>App</c> is the name of the application, which must be + started. <c>Dir</c> is the previous library directory of + <c>App</c>, the corresponding modules as well as + the old <c>.app</c> file should be located under + <c>Dir/ebin</c>. The <c>.appup</c> file should be located in + the <c>ebin</c> directory of the <em>current</em> library + directory of the application (<c>code:lib_dir(App)</c>).</p> + <p>The function looks in the <c>.appup</c> file and tries to + find an downgrade script from the current version of + the application. High-level instructions are translated to + low-level instructions and the instructions are sorted in + the same manner as when generating a <c>relup</c> script.</p> + <p>Returns <c>{ok, Script}</c> if successful.</p> + <p>Failure: If a script cannot be found, the function fails + with an appropriate error reason.</p> + </desc> + </func> + <func> + <name>eval_appup_script(App, ToVsn, ToDir, Script) -> {ok, Unpurged} | restart_new_emulator | {error, Reason}</name> + <fsummary>Evaluate an application upgrade or downgrade script</fsummary> + <type> + <v>App = atom()</v> + <v>ToVsn = ToDir = string()</v> + <v>Script -- see upgrade_script/2, downgrade_script/3</v> + <v>Unpurged = [Module]</v> + <v> Module = atom()</v> + <v>Reason = term()</v> + </type> + <desc> + <p>Evaluates an application upgrade or downgrade script + <c>Script</c>, the result from calling + <seealso marker="#upgrade_app/2">upgrade_app/2</seealso> or + <seealso marker="#downgrade_app/3">downgrade_app/2,3</seealso>, + exactly in the same way as + <seealso marker="#install_release/1">install_release/1,2</seealso> + does.</p> + <p><c>App</c> is the name of the application, which must be + started. <c>ToVsn</c> is the version to be upgraded/downgraded + to, and <c>ToDir</c> is the library directory of this version. + The corresponding modules as well as the <c>.app</c> and + <c>.appup</c> files should be located under <c>Dir/ebin</c>.</p> + <p>Returns <c>{ok, Unpurged}</c> if evaluating the script is + successful, where <c>Unpurged</c> is a list of unpurged + modules, or <c>restart_new_emulator</c> if this instruction is + encountered in the script, or <c>{error, Reason}</c> if + an error occurred when evaluating the script.</p> + </desc> + </func> + </funcs> + + <section> + <title>Typical Error Reasons</title> + <list type="bulleted"> + <item> + <p><c>{bad_masters, Masters}</c> - The master nodes + <c>Masters</c> are not alive.</p> + </item> + <item> + <p><c>{bad_rel_file, File}</c> - Specified <c>.rel</c> file + <c>File</c> can not be read, or does not contain a single + term.</p> + </item> + <item> + <p><c>{bad_rel_data, Data}</c> - Specified <c>.rel</c> file + does not contain a recognized release specification, but + another term <c>Data</c>.</p> + </item> + <item> + <p><c>{bad_relup_file, File}</c> - Specified <c>relup</c> file + <c>Relup</c> contains bad data.</p> + </item> + <item> + <p><c>{cannot_extract_file, Name, Reason}</c> - Problems when + extracting from a tar file, <c>erl_tar:extract/2</c> returned + <c>{error, {Name, Reason}}</c>.</p> + </item> + <item> + <p><c>{existing_release, Vsn}</c> - Specified release version + <c>Vsn</c> is already in use.</p> + </item> + <item> + <p><c>{Master, Reason, When}</c> - Some operation, indicated by + the term <c>When</c>, failed on the master node <c>Master</c> + with the specified error reason <c>Reason</c>.</p> + </item> + <item> + <p><c>{no_matching_relup, Vsn, CurrentVsn}</c> - Cannot find a + script for up/downgrading between <c>CurrentVsn</c> and + <c>Vsn</c>.</p> + </item> + <item> + <p><c>{no_such_directory, Path}</c> - The directory <c>Path</c> + does not exist.</p> + </item> + <item> + <p><c>{no_such_file, Path}</c> - The path <c>Path</c> (file or + directory) does not exist.</p> + </item> + <item> + <p><c>{no_such_file, {Master, Path}}</c> - The path <c>Path</c> + (file or directory) does not exist at the master node + <c>Master</c>.</p> + </item> + <item> + <p><c>{no_such_release, Vsn}</c> - The specified version + <c>Vsn</c> of the release does not exist.</p> + </item> + <item> + <p><c>{not_a_directory, Path}</c> - <c>Path</c> exists, but is + not a directory.</p> + </item> + <item> + <p><c>{Posix, File}</c> - Some file operation failed for + <c>File</c>. <c>Posix</c> is an atom named from the Posix + error codes, such as <c>enoent</c>, <c>eacces</c> or + <c>eisdir</c>. See <c>file(3)</c>.</p> + </item> + <item> + <p><c>Posix</c> - Some file operation failed, as above.</p> + </item> + </list> + </section> + + <section> + <title>SEE ALSO</title> + <p><seealso marker="doc/design_principles:release_handling">OTP Design Principles</seealso>, + <seealso marker="kernel:config">config(4)</seealso>, + <seealso marker="relup">relup(4)</seealso>, + <seealso marker="rel">rel(4)</seealso>, + <seealso marker="script">script(4)</seealso>, + <seealso marker="stdlib:sys">sys(3)</seealso>, + <seealso marker="systools">systools(3)</seealso></p> + </section> +</erlref> + |