We want node status summary on graph or pie chart on dashboard
A bit more information on what you are trying to accomplish and perhaps the amount of nodes you are trying to consolidate would be ideal. A pie chart is not currently available in the oob UI. Some customers have found unique methods for accomplishing this task using widgets such as the Custom HTML resource. However, while not a pie chart, you could certainly leverage a widget called the Custom Tile. Accessible from the widget drawer, this widget allows you to roll up the status of virtually any set of entities monitored by Orion.
There are also built in filters to allow you to specify certain sets of entities if you so choose. The widget displays the total number of entities, and the breakout of each of their status's without having to scroll through endless lists. Clicking on an object in this widget will launch the Asset Explorer and provide a list of all the entities in that state.