On-Call Role Each on-call role includes a user designated as a supervisor, who receives notifications when no one is on duty to receive Horizon notifications. The supervisor must have admin privileges. Assigning a Group to an On-Call Role Before assigning a group to an on-call role, you must create a group. Log in as a user with administrative permissions. Click the gear icon in the top right. Choose Configure OpenNMS → Configure Users, Groups and On-Call roles and select Configure On-Call Roles. Click Add New On-Call Role and specify a name, supervisor, group and description. Click Save. In the calendar, click the plus (+) icon on the day for which you want to create a schedule. Specify the user, date, and time the user should be on call and click Save: Repeat for other days and users. Click Done to apply the changes. Groups User Maintenance