Update an IBM Websphere Application Server Installation from 7.1 to 7.2

The following steps describe how to upgrade the Camunda artifacts on an IBM was application server in a shared process engine setting. For the entire migration procedure, refer to the migration guide. If not already done, make sure to download the Camunda BPM 7.2 IBM was distribution.

The upgrade procedure takes the following steps:

  1. Uninstall the Camunda libraries and archives
  2. Add the new Camunda libraries
  3. Install optional Camunda dependencies
  4. Configure process engines
  5. Create a shared Camunda library
  6. Install the Camunda archive
  7. Install the Camunda BPM web applications
  8. Associate existing applications with shared library

In each of the following steps, the identifiers $*_VERSION refer to the current version and the new versions of the artifacts.

Changing Platform Configuration

Depending on your chosen feature set for Camunda BPM, some of the (optional) migration steps may require to change the configuration of the BPM platform. The Camunda enterprise archive (EAR) contains a default platform configuration. If you want to change this configuration, you can replace it as described in the deployment descriptor reference.

1. Uninstall the Camunda Libraries and Archives

First, uninstall the Camunda web applications, namely the Camunda REST API (artifact name like camunda-engine-rest) and the Camunda applications Cockpit, Tasklist and Admin (artifact name like camunda-webapp).

Uninstall the Camunda EAR. Its name should be camunda-ibm-was-ear-$PLATFORM_VERSION.ear. Then, uninstall the Camunda job executor adapter, called camunda-ibm-was-rar-$PLATFORM_VERSION.rar. Delete the J2E connection factory and activation specification created for Camunda BPM 7.1.

After stopping the server, delete all Camunda BPM related libraries from the $WAS_HOME/lib/ext directory. These should be:

  • camunda-engine-$PLATFORM_VERSION.jar
  • camunda-bpmn-model-$PLATFORM_VERSION.jar
  • camunda-xml-model-$PLATFORM_VERSION.jar
  • mybatis-$MYBATIS_VERSION.jar
  • java-uuid-generator-$VERSION.jar
  • joda-time-$VERSION.jar
  • slf4j-api-$VERSION.jar

Note that the non-Camunda artifacts may be depended on by other applications.

2. Add the New Camunda Libraries

Camunda BPM 7.2 ships a new installation approach for the Camunda BPM platform on IBM was. The Camunda BPM libraries are now available through a shared library the server administrator has to create.

Copy the Camunda core modules from the folder $WAS_DISTRIBUTION/modules/lib to a folder that can be referenced from your IBM was installation when you later create the shared library. In detail, these are the following artifacts:

  • camunda-engine-$PLATFORM_VERSION.jar
  • camunda-bpmn-model-$PLATFORM_VERSION.jar
  • camunda-cmmn-model-$PLATFORM_VERSION.jar
  • camunda-xml-model-$PLATFORM_VERSION.jar
  • mybatis-$MYBATIS_VERSION.jar
  • java-uuid-generator-$VERSION.jar
  • joda-time-$VERSION.jar
  • slf4j-api-$VERSION.jar

If you have been previously using the Camunda LDAP plugin, also copy the following artifact:

  • camunda-identity-ldap-$PLATFORM_VERSION.jar

3. Install Optional Camunda Dependencies

There are artifacts for Camunda Connect, Camunda Spin, the Freemarker template language and Groovy scripting that may optionally be added to the shared library folder. Since all these artifacts add new functionality, the following steps are not required for migration.

Note: The default Camunda configuration file contained by the Camunda EAR automatically activates the newly introduced, optional Camunda dependencies, Camunda Spin and Connect. If you do not use a custom BPM platform configuration as described here and do not intend to do so, you must install the Camunda Spin and Connect core libraries to the shared libraries folder.

Not Using Connect/Spin

If you do not want to use Camunda Connect or Camunda Spin, you cannot use the default BPM platform configuration that is contained in the Camunda EAR. In this case, make sure to change the configuration location as described [here][configuration-location]. As a starting point, you can copy the default configuration from $WAS_DISTRIBUTION/modules/camunda-ibm-was-ear-$PLATFORM_VERSION.ear/camunda-ibm-was-service-$PLATFORM_VERSION.jar/META-INF/bpm-platform.xml and remove the <plugin> entries for the classes ConnectProcessEnginePlugin and SpinProcessEnginePlugin.

Camunda Connect

If Camunda Connect is intended to be used, copy the following library from $WAS_DISTRIBUTION/modules/lib to the Camunda shared library folder:

  • camunda-connect-core-$CONNECT_VERSION.jar
  • camunda-commons-logging-$COMMONS_VERSION.jar
  • camunda-commons-utils-$COMMONS_VERSION.jar
  • slf4j-api-$SLF4J_VERSION.jar

If you use a custom BPM platform configuration file, Camunda Connect functionality has to be activated for a process engine by registering a process engine plugin (note that if you use the default configuration, this step is not necessary):

<?xml version="1.0" encoding="UTF-8"?>
<bpm-platform ... >
  <process-engine name="default">
    ...
    <plugins>
      ... existing plugins ...
      <plugin>
        <class>org.camunda.connect.plugin.impl.ConnectProcessEnginePlugin</class>
      </plugin>
    </plugins>
    ...
  </process-engine>

</bpm-platform>

Camunda Spin

If Camunda Spin is intended to be used, copy the following library from $WAS_DISTRIBUTION/modules/lib to the Camunda shared library folder:

  • camunda-spin-core-$CONNECT_VERSION.jar
  • camunda-commons-logging-$COMMONS_VERSION.jar
  • camunda-commons-utils-$COMMONS_VERSION.jar
  • slf4j-api-$SLF4J_VERSION.jar

If you use a custom BPM platform configuration file, Camunda Spin functionality has to be activated for a process engine by registering a process engine plugin (note that if you use the default configuration, this step is not necessary):

<?xml version="1.0" encoding="UTF-8"?>
<bpm-platform ... >
  <process-engine name="default">
    ...
    <plugins>
      ... existing plugins ...
      <plugin>
        <class>org.camunda.spin.plugin.impl.SpinProcessEnginePlugin</class>
      </plugin>
    </plugins>
    ...
  </process-engine>

</bpm-platform>

Groovy Scripting

If Groovy is to be used as a scripting language, add the following artifacts to the Camunda shared library folder:

  • groovy-all-$GROOVY_VERSION.jar

Freemarker Integration

If the Camunda integration for Freemarker is intended to be used, add the following artifacts to the Camunda shared library folder:

  • camunda-template-engines-freemarker-$TEMPLATE_VERSION.jar
  • freemarker-2.3.20.jar
  • camunda-commons-logging-$COMMONS_VERSION.jar
  • camunda-commons-utils-$COMMONS_VERSION.jar
  • slf4j-api-$SLF4J_VERSION.jar

4. Configure Process Engines

Script Variable Storing

As of 7.2, the default behavior of script variables has changed. Script variables are set in e.g. a BPMN Script Task that uses a language such as JavaScript or Groovy. In previous versions, the process engine automatically stored all script variables as process variables. Starting with 7.2, this behavior has changed and the process engine does not automatically store script variables any longer. You can re-enable the legacy behavior by setting the boolean property autoStoreScriptVariables to true for any process engine in the bpm-platform.xml:

<?xml version="1.0" encoding="UTF-8"?>
<bpm-platform ... >
  ...
  <process-engine name="default">
    ...
    <properties>
      ... existing properties ...
      <property name="autoStoreScriptVariables">true</property>
    </properties>
    ...
  </process-engine>
  ...
</bpm-platform>

As an alternative, process application developers can migrate script code by replacing all implicit declarations of process variables in their scripts with an explicit call to execution.setVariable('varName', 'value').

5. Create a Shared Camunda Library

Next, start up the server and create a shared library named Camunda for these artifacts. In detail, go to Environment / Shared libraries, choose the correct scope in which your EAR and applications will run and define a new shared library. Name it Camunda. This name is mandatory. Enter as classpath the path where you have copied the Camunda shared libraries, e.g., /opt/IBM/was/AppServer/profiles/AppSrv01/camunda-shared-libs. Enable the Use an isolated class loader for this shared library checkbox.

JDBC Drivers, DataSource and WorkManager settings stay the same as compared to 7.1.

6. Install the Camunda Archive

Install the Camunda EAR, i.e., the file $WAS_DISTRIBUTION/modules/camunda-ibm-was-ear-$PLATFORM_VERSION.ear. During the installation, the EAR will try to reference the previously created Camunda shared library.

As of version 7.2, the Camunda job executor resource adapter (RAR) that you uninstalled in step 1 is part of the Camunda EAR and therefore does not need to be installed separately.

7. Install the Camunda Web Applications

Camunda REST API

The following steps are required to upgrade the Camunda REST API on an IBM was instance:

  1. Deploy the web application $WAS_DISTRIBUTION/webapps/camunda-engine-rest-$PLATFORM_VERSION-was.war to your IBM was instance.
  2. Associate the web application with the Camunda shared library.

Camunda Cockpit, Tasklist, and Admin

The following steps are required to upgrade the Camunda web applications Cockpit, Tasklist, and Admin on an IBM was instance:

  1. Deploy the web application $WAS_DISTRIBUTION/webapps/camunda-webapp-ee-was-$PLATFORM_VERSION.war to your IBM was instance.
  2. Associate the web application with the Camunda shared library.

8. Associate Existing Applications with Shared Library

The new shared Camunda library affects process applications as well because the Camunda BPM libraries which are available with 7.1 on the global classpath are gone. In order to make the Camunda libraries available to applications, the Camunda shared library has to be associated with every process application. If this is not done, the applications fail due to missing resources.

LDAP Entity Caching

With 7.2, it is possible to enable entity caching for Hypertext Application Language (HAL) requests that the camunda web applications make. This can be especially useful when you use camunda in combination with LDAP. To activate caching, the camunda webapp artifact has to be modified and the pre-built application cannot be used as is. See the REST Api Documentation for details.

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