Hi!
You can use the SOAP-based Webservice-API to call workflows. See the documentation for details:
http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vcenter-orchestrator-42-develop-web-se...
In the examples-package on the documentation page there is a ready-to-use clients for java.
For other clients (powercli, wavemaker) and a walkthrough through the examples see here:
http://www.vcoportal.de/category/integrate-vco/external-workflow-calls/
However, when using the API you still have to login (=> present a username/password for every call).
Other ways to call workflows from outside:
- let the external system set a flag (in a database, creat a file in a certain directory,... ) and create a "polling" workflow as scheduled task, which looks e.g. every 5 minutes if the flag is set.
- use events for the AMQP or the SNMP plugin
- create your own plugin with custom triggers
If you plan a tight integration in your external system, also a worthy read:
http://communities.vmware.com/docs/DOC-17097
Cheers,
Joerg