In cloud systems, services constituting a transaction may spread over a large number of servers or clusters. Theoretically, these services could consume cloud resources unlimitedly. To avoid financial loss due to resource overuse, clouds have to monitor the state of resources consumed by the services – collect values of consumption, and evaluate whether the combined usage of resources has excessed a pre-defined upper bound or not. The distributed nature of the services introduces a challenge to the monitoring system on how to summarise distributed state information with low cost. We present our resource state monitoring solution to capture the challenge introduced by services hosted in clouds. Our solution tracks the resource consumed by each service constituting a transaction individually whilst ensures the whole transaction does not overuse the allocated resource. It improves availability by avoiding single points of failure, and achieves scalability by minimising message exchanges.We performed experimental analyses that indicate this work can provide an inexpensive resource monitoring solution for transactions in clouds.