Checking our demo, it seems that you can choose to filter by "Instance" if you select the BookingService from process group "eT-demo-1-BusinessBackend". The others (VMWare and OpenStack) do not offer this options as a filter.
Are you sure the instance filtering @Gabriel P. was referring to is not what you're looking for?
As can be seen below, you can create a filter based on instance, which is the host on which the service is running:
Here is the host list, where you can see the BB1 and BB2-apache-tomcatjms-iis hosts listed:
Maybe I'm still misunderstanding, but wanted to make sure this wasn't actually what you were looking for.
Thanks for the screenshot @Hayden M., definitely made it more clear than my comment.
@Raffaele T., I think it may be related to technology. Your screenshot is probably from one of the other process groups like VMWare or OpenStack. They do not offer the "Instance" option as a filter.
Please click on "BookingService" on your breadcrumb and then expand "Properties and tags".
If the Process group is "eT-OpenStack-BusinnessBackend" or "eT-vmware-demo-1-BusinessBackend", it won't give you the option to filter by instance.
However, if it is "eT-demo-1-BusinessBackend", then you will be able to filter by Instance, as Hayden's screenshot demonstrated.
The instance feature is also available on cloud foundry or other cloud instances. It is rather independent of the underlying infrastructure.
If you have 5 nodes in cloudfoundry then you have 5 instances.
basically you will always have at least one instance regardless of how and where it runs.
An instance of a service is just an instance on a particular process. A service runs on a process group which encompass many processes but at least one. so a service will always have at least one instance. However if the service you are looking at only has a single instance then the filter option is not shown. This also means that if the requests you already filtered down to are only on a single instance then the filter option is also not shown. The instance filter was added quite a while ago so the version shouldn't really matter.