Adding a Cluster Node
Overview
When you install Universal Controller, you create a single instance (cluster node) of the Controller. To operate Universal Automation Center in a High Availability (HA) environment, you must add one or more cluster nodes. Each cluster node should be installed on a separate machine.
This page tells you how to add one or more cluster nodes.
Requirements for Adding a Cluster Node
Each cluster node in an HA environment must connect to the same Universal Controller database. If one of the cluster nodes stops processing, another cluster node continues processing with the same data.
Each cluster node in an HA environment must be the same version and build of the Controller. To ensure this, you can either:
Install the downloaded version of the Controller on a second machine.
Download a new version of the Controller software, update the current version, and then install the new version on a second machine.
It is strongly recommended that an HA environment has at least two OMS Servers, although you do not need an OMS Server for every cluster node if your HA environment contains three or more cluster nodes.
Procedure for Adding a Cluster Node
This page describes the following procedure:
This procedure assumes you already have performed any required pre-installation procedure steps for the cluster node being added.
Copy and Unpack the Universal Controller Distribution File
Copy the downloaded distribution file, which was used to install the current, single instance of Universal Controller, from its current location to the machine on which you want to install a new instance of the Controller.
To unpack the Universal Controller distribution file, use the following method appropriate for your platform:
Linux/Unix |
|
|---|---|
Windows | Use an appropriate archiving / unzipping product. |
Install the Controller
To install the Controller, issue the following command that is appropriate for your platform:
Linux |
|
|---|---|
Windows |
|
You must include command line switches that specify information the Controller needs to access the Tomcat installation directory, the war file, and the database. You can include additional command line switches, but they are not required.
If a required command line switch is missing from the command line, an error message will identify it during the installation process.
The Controller installation process writes the values for some command line switches to the Universal Controller start-up properties file, uc.properties (see the table, below). For any of those command line switches that are not required and, in fact, are not included on the command line, the Controller installation process writes their default value to uc.properties.
Command Line Switches
The following table describes the command line switches for the Controller installation process and identifies which are required.
For command line switches that have their value written to the Universal Controller start-up properties file, uc.properties, the table also identifies the property in that file to which the value is written.
Note
All command line switches are case-sensitive.
Command Line Switch | Description | Default | Required | Controller Property | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Full path of the Universal Controller war file from the downloaded Universal Controller package. | none | Yes |
| ||||||||
| Universal Controller database name. | uc | No | uc.db.name= | ||||||||
| Database user's password. | none | Yes | uc.db.password= | ||||||||
| JDBC connection URL.
| jdbc:mysql://localhost | No | uc.db.url= | ||||||||
| Database user name. | none | Yes | uc.db.user= | ||||||||
| Used by the Universal Controller to generate a unique Cluster Node Node Id in the format of hostname:port-dbname. Note This is meant to represent the value of the Tomcat HTTP/1.1 Connector port configured in the server.xml. It is used solely for Node Id generation and does not impact the Tomcat HTTP/1.1 Connector configuration. | 8080 | No | uc.servlet.port | ||||||||
| Database type.
* --rdbms is required if --dburl is used in the command. | mysql | No * | uc.db.rdbms= | ||||||||
| Path to the Tomcat installation directory (contains the directories: | none | Yes |
|