I'm looking for a way to indicate statuses using colors. For example, if CPU goes more than 90% Red color, less than 50% Green color etc. Could you suggest any widget exists for this kind of UI requirement?
You can use a single-value visualization, where you can set a rangemap for color-coding. See Single value visualization in the Dashboards and Visualizations manual. You can also use a radial gauge, as aweitzman suggested, or another type of gauge (see the link aweitzman provided, it is in the same topic).