Appboard/old/multiple instances

There are some special cases where you may want to install more than one instance of AppBoard on the same server. This article details some special considerations to make this work properly.

Uses

The following are some sample cases where you may want to install more than one instance of AppBoard on the same server:

• Testing - The test team needs to have multiple versions of the system available so they can validate the functionality and features aainst one another.
• Development - A developer is working on multiple AppBoard development projects at the same time.
• Staging - A production and dev system are both running on the production server. They can be swapped, for example, to make the dev system become the production system after validation is complete and certified.
• Demos - Multiple demo systems can be created and provided at the same time for review.

Configuration

Review the following items to make sure each of the AppBoard instances is configured properly.

Port Configuration

When installing more than one instance of AppBoard on the same server, the most important item to configure is the ports. There are two ports used by each instance, and they must be unique for each system. If you start an AppBoard system, and it tries to use a port that is already in use, you will receive a JVM Bind Error, and the system will not start.

Perform the following steps to adjust the AppBoard port configuration for each instance on the server:

1. Open the following file in a text editor: [APPBOARD_HOME]/server/bin/setenv.bat (Windows) or setenv.sh (Unix)
2. Search for the string "SHUTDOWN_PORT" to locate the configuration of the shutdown port. You should see a line such as the following:

   set SHUTDOWN_PORT=8005

3. Make sure this is set to a unique shutdown port value that is not already in use by another AppBoard instance or other Tomcat application on the same server. Change the port, if needed by editing the file setenv-custom.bat (Windows) or setenv-custom.sh (Unix). For example, add:

   (Windows): set SHUTDOWN_PORT=8006

   (Unix): SHUTDOWN_PORT=8006

4. Search for "HTTP_PORT" to locate the configuration of the main Tomcat startup port. You should see a line such as the following:

   set HTTP_PORT=8080

5. Notice the port setting in the above example. Make sure this is set to a unique startup port value that is not already in use by another AppBoard instance or other Tomcat application on the same server. Change the port, if needed, by editing the file setenv-custom.bat (Windows) or setenv-custom.sh (Unix). For example, add:

   (Windows): set HTTP_PORT=8081

   (Unix): HTTP_PORT=8081

The redirectPort is only used when SSL is enabled, to re-direct non-SSL requests to SSL. You can change this to a unique value also, to ensure that there will not be a conflict. However, unlike the shutdown and startup ports, you are able to start multiple instances that have the same redirectPort setting.

Memory Configuration

When running multiple AppBoard instances on the same server, the system administrator should consider the memory capacity of the server. If the System Requirements recommend 2 GB of RAM for AppBoard, it would be advisable for example to have 4 GB of RAM if two instances will be running on the same server.

One way to limit the memory footprint of AppBoard is in the Tomcat memory configuration settings. For a dev or demo instance, you can typically lower the Java Virtual Machine (JVM) maximum heap size (-Xmx JVM parameter) to a low setting such as -Xmx512m. without any noticeable change in performance.

Database

If you are using the default AppBoard database settings and the embedded local AppBoard H2 database, no special configuration is required to run multiple instances on the same server. Each instance ill use it's own database.

If your system is configured to access an external database, such as Oracle or MySQL, then care must be taken. If you have two systems running locally that are accessing the same database, unpredictable results may occur. For example, if you add a test User on the dev instance, and this is connected to the same database as the production instance, the test User will also appear in the production instance.