Recent embedded systems are dramatically increasing their features to satisfy a user's demanding requirements. In traditional approaches, each feature uses a dedicated processor to be implemented, but the approach increases the cost to develop highly functional embedded systems. A multi-core processor offers a new opportunity to solve the dilemma because various functionalities can be implemented on one multi-core processor. While the number of functionalities is increased, we can just add more cores in the multi-core processor. However, we need a desirable software platform to implement a large number of functionalities on a multi-core processor for developing highly functional embedded systems. A composition kernel makes it possible to compose multiple functionalities on a multi-core processor with the minimum modifications of OS kernels and applications. In this paper, we present SPUMONE, a composition kernel for developing highly functional embedded systems, and runs on the SH4-based multi-core processor. SPUMONE does not support the spatial isolation to isolate guest OSes not to sacrifice the performance due to its virtualization. The approach may sacrifice the reliability and security, so we also propose to add the monitoring service that runs in the outside of a target guest OS to enhance its reliability and security without relying on the spatial isolation.