Resource Monitor

The VOLTTRON™ Restricted additions provide additional protection against an agent consuming too many resources to the point of the host system becoming unresponsive or unstable. The resource monitor uses Linux control groups (or cgroups) to limit the CPU cycles and memory an individual agent may consume, preventing its possible overconsumption from adversely affecting other agents and services on the system. The resource requirements of an agent are set in its resource contract when provisioning an agent for service.

When a request is made to move an agent to a new platform, part of the validation of the agent includes checking its resource contract against resources currently available on the system. If the resources are available and the agent has passed all other validation, the agent will be executed and retain those resource guarantees throughout its lifetime on that platform. If the agent, however, requests memory or CPU cycles that are not available, its move request is denied and it will not execute on the requested platform.

Once an agent has been assigned resources, it is the responsibility of that agent to manage its resources. While an agent may exceed its resource guarantees when system utilization is low, when resources given to other agents are required, an agent exceeding the use in its contract may be terminated.