Testing a new configuration against a current cluster

You can use the apicup utility to test the validity of a new configuration before you install it.

The apicup utility is used to set configuration properties for subsystems on API Connect on VMware appliances. The utility can be used for installation, upgrade, and maintenance activities such as backup and restore.

The usage pattern is to set values for each parameter you need for a subsystem, and then deploy the new values with the apicup subsys install command.

You can use the --dry-run option to test the validity of your values prior to deploying them to an existing cluster:

apicup subsys install <subsystem_name> --dry-run

Important: You cannot use apicup subsys install <SUBSYS> --dry-run for a fresh install or an upgrade. The --dry-run feature is for testing proposed configuration changes on an existing cluster.

For example, if you want to configure S3 backups for you management subsystem, the command flow is:

Follow the instructions for configuring S3 backupsReconfiguring backup settings for the management subsystem by issuing the required apicup subsys set commands:
```
apicup subsys set mgmt <setting>=<value>
apicup subsys set mgmt <second_setting>=<value>
apicup subsys set mgmt <third_setting>=<value>
.
.
.
```

Do a dry run of the install command:

apicup subsys install mgmt --dry-run

Example message on success:

managementcluster.management.apiconnect.ibm.com/management configured (server dry run)

Example message on failure:

Error: Failed to execute dry-run:....

The error message also contains details about the error.

When dry run returns success, deploy:
```
apicup subsys install mgmt
```