Comment 0 for bug 1553214

When a customer selects Ironic in MOS he assumes that Ironic will works 'from a box'.
Some parameters needs to be tuned to get maximum capability.

Nova:
max_concurrent_builds can be increased to 50
scheduler_host_subset_size = 10000
This parameter should be is near total amount of baremetal servers in the cloud. It defines how nova scheduler map instance to hypervisor. If this value is less than number of simultaneous boot requests to nova, there is a high chance that nova will try to map 2 Instances to same hypervisor, it leads to failure of one of instances as result of scheduller_max_attemp is reached (default 3). Instance marked as ERROR.
Nova claims in API should solve this problem.

ironic.nova.compute.manager.ClusteredComputeManager: at the moment during instance termination Ironic initiates resource update for all nodes. It leads to high performance degradation during intensive cloud usage (adding/deleting nodes simultaneously) with high number of nodes. Resource update should be disabled on instance termination or we should update resources for specific instance only 1, 2 .

Fuel-agent: doesn’t support UEFI shell. UEFI shell should be disabled manually by administrator before enrolling node to Ironic.