Update a Tomcat Installation from 7.2 to 7.3

The following steps describe how to upgrade the Camunda artifacts on a Tomcat 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 7.3 Tomcat distribution.

The upgrade procedure takes the following steps:

  1. Upgrade the Camunda BPM core libraries
  2. Upgrade the optional Camunda BPM libraries
  3. Upgrade Camunda web applications
  4. Configure Process Engines

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

Upgraded Tomcat Version

The pre-built Camunda 7.3 distribution ships with Tomcat 7.0.62, whereas 7.2 comes with Tomcat 7.0.50. Camunda 7.3 is supported on all Tomcat 67 versions such that a Tomcat upgrade is not required when migrating from 7.2 to 7.3.

Should you want to upgrade Tomcat along with Camunda, perform the following steps either before or after upgrading Camunda:

  • Copy all your Camunda-related libraries from $TOMCAT_HOME/lib to the new Tomcat server’s lib-directory.
  • Apply all modifications to Tomcat configuration files such as server.xml/bpm-platform.xml to the files located in the new Tomcat server’s directory.
  • Undeploy all process applications and copy them to the new Tomcat server’s directory for redeployment.

See the Tomcat migration guide for any Tomcat-specific migration notes and procedures.

1. Upgrade the Camunda BPM Core Libraries

Replace the following libraries in the folder $TOMCAT_HOME/lib/ with their new versions from the folder $TOMCAT_DISTRIBUTION/lib/:

  • camunda-engine-$PLATFORM_VERSION.jar
  • camunda-bpmn-model-$PLATFORM_VERSION.jar
  • camunda-cmmn-model-$PLATFORM_VERSION.jar
  • camunda-xml-model-$PLATFORM_VERSION.jar

2. Upgrade Optional Camunda BPM libraries

In addition to the core libraries, there may be optional artifacts in $TOMCAT_HOME/lib/ for LDAP integration, Camunda Connect, and Camunda Spin. If you use any of these extensions, the following upgrade steps apply:

LDAP Integration

Copy the following libraries from $TOMCAT_DISTRIBUTION/lib to the folder $TOMCAT_HOME/lib/ if present:

  • camunda-identity-ldap-$PLATFORM_VERSION.jar

Camunda Connect

Copy the following libraries from $TOMCAT_DISTRIBUTION/lib to the folder $TOMCAT_HOME/lib/ if present:

  • camunda-connect-connectors-all-$CONNECT_VERSION.jar
  • camunda-connect-core-$CONNECT_VERSION.jar
  • camunda-engine-plugin-connect-$PLATFORM_VERSION.jar

Camunda Spin

Copy the following libraries from $TOMCAT_DISTRIBUTION/lib to the folder $TOMCAT_HOME/lib/ if present:

  • camunda-spin-dataformat-all-$SPIN_VERSION.jar
  • camunda-spin-core-$SPIN_VERSION.jar
  • camunda-engine-plugin-spin-$PLATFORM_VERSION.jar

3. Upgrade Web Applications

Upgrade REST API

The following steps are required to upgrade the camunda REST API on a Tomcat instance:

  1. Undeploy an existing web application with a name like camunda-engine-rest
  2. Download the REST API web application archive from our Maven Nexus Server Or switch to the private repository for the enterprise version (User and password from license required). Choose the correct version named $PLATFORM_VERSION/camunda-engine-rest-$PLATFORM_VERSION-tomcat.war.
  3. Deploy the web application archive to your Tomcat instance.

Upgrade Cockpit, Tasklist, and Admin

The following steps are required to upgrade the camunda web applications Cockpit, Tasklist, and Admin on a Tomcat instance:

  1. Undeploy an existing web application with a name like camunda-webapp
  2. Download the Camunda web application archive from our Maven Nexus Server). Or switch to the private repository for the enterprise version (User and password from license required). Choose the correct version named $PLATFORM_VERSION/camunda-webapp-tomcat-$PLATFORM_VERSION.war.
  3. Deploy the web application archive to your Tomcat instance.

LDAP Entity Caching

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.

4. Configure Process Engines

Task Query Expressions

As of 7.3.3, the default handling of expressions submitted as parameters of task queries has changed. Passing EL expressions in a task query enables execution of arbitrary code when the query is evaluated. The process engine no longer evaluates these expressions by default and throws an exception instead. This behavior can be toggled in the process engine configuration using the properties enableExpressionsInAdhocQueries (default false) and enableExpressionsInStoredQueries (default true). To restore the engine’s previous behavior, set both flags to true. See the user guide on security considerations for custom code for details. This is already the default for Camunda BPM versions after and including 7.2.8.

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