Configuring bindings

Bindings are needed in order to start applications. A binding is a mapping from a node type, which the application defines, to a set of hosts. So, in order to start an application on a particular host, there has to exist at least one binding that associates the application (and its node type) with that host.

The bindings are also used to govern the minimum and maximum number of application node instances that should be allowed. This means that if a binding is configured with a minimum of 2, the grid will always try to make sure that at least two application node instances referenced by that binding are running in the grid. If the number of nodes becomes fewer than the configured value, the grid will automatically start nodes until the minimum is met.

The maximum works in the same but reverse way. It is impossible to start more application node instances using this binding than the configured maximum. It should be noted that the maximum is soft-enforced, if some condition arises which means the running node count exceeds the maximum value, the Grid will not terminate a node to enforce the constraint.

It is also possible to configure the initial number of application nodes you want for a binding. If configured, the initial value will be considered when the application starts. In fact, starting applications is just a matter of honoring the initial value for all the bindings that belong to the application.

Also, as described in Grid properties, the bindings are one of the different contexts that you may use when defining property overrides. This enables you to define different property values for your application depending on which binding is used to do the launch. Configuring bindings is done from the Configuration Manager.

To configure bindings

  1. Navigate to the Configuration Manager.
  2. Click the Applications link.
  3. In the list, select the application you want to configure bindings for.
  4. To add a binding, click the Add link in the Bindings frame. To edit existing bindings, click one of the bindings in the list on the page. For more details, see Edit Application.