This seems to be by design i.e. Scheduler can get out of sync, and we have the claim-and-retry mechanism in place so request for vm3 would fail and trigger a reschedule.
** Changed in: nova Status: Confirmed => Invalid -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1370207 Title: race condition between nova scheduler and nova compute Status in OpenStack Compute (nova): Invalid Bug description: This is for nova 2014.1.2. Here, nova DB is the shared resources between nova-scheduler and nova- compute. Nova-scheduler checks DB to see if hv node can meet the provision requirement, nova-compute is the actual process to modify DB to reduce the free_ram_mb. For example, current available RAM on hv is 56G, with ram_allocation_ration=1.0. Within a minute, 3 vm provision requests are coming to scheduler, each asking for 24G RAM. t1: scheduler gets a request for vm1, assign vm1 to hv t2: scheduler gets a request for vm2, assign vm2 to hv t3: vm1 is created, nova-compute updates nova DB with RAM=32G t4: scheduler gets a request for vm3, assign vm3 to hv t5: vm2 is created, nova-compute updates nova DB with RAM=8G t6: vm3 is created, nova-compute updates nova DB with RAM=-16G In the end, we have a negative RAM with ram_allocation_ratio=1.0. To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1370207/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp