We should consider making SLRP update its resources periodically, or adding an endpoint to trigger that, for the following reasons:
1. Mesos currently assumes all profiles have disjoint storage pools. This is because Mesos models each resource independently. However, in practice an operator can set up, say two profiles, one for linear volumes and one for raid volumes, and an "LVM" resource provider that can provision both linear and raid volumes. The correlation between the storage pools of the linear and raid profiles would reduce one's pool capacity when a volume of the other type is provisioned. To reflect the actual sizes of correlated storage pools, we need a way to make SLRP update its resources.
2. The SLRP now only queries the CSI plugin to report a list of volumes during startup, so if a new device is added, the operator will have to restart the agent to trigger another SLRP startup, which is inconvenient.