I want to send an event from child server to parent to be used in an alarm. Is it possible?
There are two ways to establish a parent-child relation between servers/sites: Milestone Federated Architecture and Milestone Interconnect. What you need might be different depending on which of these you have.
In Milestone Federated Architecture the Smart Client will automatically read the events and alarms of the child site when logged in on the parent site.
There is no mechanism out of the box to send the same events to a parent site. You can using the MIP SDK implement an application or a plugin that can send the same events to the parent server.
I want to create an alarm on parent triggered by an alarm/event on child. How can this be done?
The parent knows the child exist. The child does not know that a parent exist. So I would like to suggest that you implement a parent component that listen for events in the children, it could then inject the same events in the parent. Try to explore the Multi-Site Status Viewer sample. https://doc.developer.milestonesys.com/html/index.html?base=samples/multisitestatusviewer.html&tree=tree_2.html