Hi, A design issue is observed in ceilometer service of Openstack. Setup include multiple compute nodes and 3 controller nodes. Meters from each compute node are sent to all the 3 ceilometer instances via RabbitMQ in round robin fashion at an interval of 10 min. After transformation of cumulative cpu meter data, cpu_util is generated by ceilometer instance at controller node and is published to the http address configured in ceilometer pipeline configuration. cpu_util is used by the application to take the decision if scaling of VM needs to be triggered or not. Ceilometer instance calculates cpu_util for a VM from the difference between cumulative cpu usage of VM at two timestamp divided by the timestamp difference. Let's say 1 compute node send the cumulative cpu usage of a VM (C1, C2, C3, C4) at timestamp T1, T2, T3, T4 (difference between any two timestamp is 10 min). Now (C1,T1) & (C4,T4) tuple is received by ceilometer instance 1, (C2,T2) by instance 2, (C3,T3) by instance 3. Here even if CPU usage of VM is increased between T1 & T2, cpu_util is calculated for 30 min duration (T1 & T4) rather than as expected for 10 min. This leads to scaling getting triggered after T4 that too when CPU usage is consistently above the threshold between T1 and T4. Please suggest how could this issue could be resolved. Do we have any solution to bind VM or compute node meter data to specific ceilometer instance for processing? Regards, Arvind. "Confidentiality Warning: This message and any attachments are intended only for the use of the intended recipient(s). are confidential and may be privileged. If you are not the intended recipient. you are hereby notified that any review. re-transmission. conversion to hard copy. copying. circulation or other use of this message and any attachments is strictly prohibited. If you are not the intended recipient. please notify the sender immediately by return email. and delete this message and any attachments from your system. Virus Warning: Although the company has taken reasonable precautions to ensure no viruses are present in this email. The company cannot accept responsibility for any loss or damage arising from the use of this email or attachment."