As mentioned earlier, a monitoring template can be applied to one or more targets of the same target type, or to composite targets such as groups. For composite targets, the template is applied to all member targets that are of the appropriate type. If you applied the template manually or via EM CLI, once a template is applied, future changes made to the template will not be automatically propagated to the targets: You must reapply the template to all affected targets

Administration Groups and Template Collections: Applying Monitoring Templates Automatically

Monitoring templates can be automatically applied whenever a new targets are added to your Enterprise Manager environment. Automation is carried out through Administration Groups and Template Collections Administration Groups are a special type of group used to automate application of monitoring settings to targets upon joining the group. When a target is added to the administration group Enterprise Manager applies monitoring settings from the associated template collection consisting of monitoring templates, compliance standards, and Enterprise Manager policies. If changes are later made to the monitoring template, Enterprise Manager automatically applies the changes to the relevant targets based on the synchronization schedule. For more information, see "Using Administration Groups".