Public bug reported: Ironic nodes can only be assigned to a single instances. So resource allocation is "all or nothing" - i.e. if an instance is spawned on a node all the resources become unavailable no mater how much was stated in the flavor used. The view of the resource tracker does not match this behavior, leading to attempts to spawn instances that can not be accommodated.
More specifically, when an instance is sent to a host manager to spawn, the resource tracker for a target node will test to see if the node has sufficient resources to accept the instance. This test checks to see if the amount of resource available on the host (ram, disk, cpu, etc.) is more than the amount requested. If the instance passes this test, the resource tracker will deduct the amount of resource requested from the amount that is available. This may leave a lesser amount still available. If there is a subsequent instance sent for that node, the resource tracker will accept it if the amount of resource it requests is less than the remaining amount available. In ironic, spawning an instance will result in no resources left available on that host. So the resource tracker has the wrong view of how much resource is available at the node. Note that the ironic driver is complemented by an ironic version of the host manager at the scheduler that does do the right thing for ironic in its consume method. However, its values are overridden by those retrieved from the resource tracker, so it is overridden by the values provided by the resource tracker. Also, the get_available_resource() method on the ironic virt driver returns the correct resource availability to the resource tracker, but the resource tracker only uses the resource totals and recalculates the availability, thus overriding the values from the driver as well. Resource tracking can only work with ironic if the exact match filters are used. In which case it works by coincidence. The resource tracker resource consumption should be specialised to deal with ironic nodes correctly. ** Affects: nova Importance: Undecided Status: New -- 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/1402658 Title: resource tracking is incorrect for ironic Status in OpenStack Compute (Nova): New Bug description: Ironic nodes can only be assigned to a single instances. So resource allocation is "all or nothing" - i.e. if an instance is spawned on a node all the resources become unavailable no mater how much was stated in the flavor used. The view of the resource tracker does not match this behavior, leading to attempts to spawn instances that can not be accommodated. More specifically, when an instance is sent to a host manager to spawn, the resource tracker for a target node will test to see if the node has sufficient resources to accept the instance. This test checks to see if the amount of resource available on the host (ram, disk, cpu, etc.) is more than the amount requested. If the instance passes this test, the resource tracker will deduct the amount of resource requested from the amount that is available. This may leave a lesser amount still available. If there is a subsequent instance sent for that node, the resource tracker will accept it if the amount of resource it requests is less than the remaining amount available. In ironic, spawning an instance will result in no resources left available on that host. So the resource tracker has the wrong view of how much resource is available at the node. Note that the ironic driver is complemented by an ironic version of the host manager at the scheduler that does do the right thing for ironic in its consume method. However, its values are overridden by those retrieved from the resource tracker, so it is overridden by the values provided by the resource tracker. Also, the get_available_resource() method on the ironic virt driver returns the correct resource availability to the resource tracker, but the resource tracker only uses the resource totals and recalculates the availability, thus overriding the values from the driver as well. Resource tracking can only work with ironic if the exact match filters are used. In which case it works by coincidence. The resource tracker resource consumption should be specialised to deal with ironic nodes correctly. To manage notifications about this bug go to: https://bugs.launchpad.net/nova/+bug/1402658/+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