Add NovaSchedulerMaxAttempts parameter

Needed by the Undercloud installer. Defaults to 3 to match
what we do in puppet-tripleo today for the Overcloud.

Change-Id: Ib4ea5af26c39e466d0f4b7506a65f020620f2120

environments/undercloud.yaml

@@ -15,6 +15,7 @@ parameter_defaults:
   NeutronDnsDomain: ''
   NovaSchedulerAvailableFilters: 'tripleo_common.filters.list.tripleo_filters'
   NovaSchedulerDefaultFilters: ['RetryFilter', 'TripleOCapabilitiesFilter', 'ComputeCapabilitiesFilter', 'AvailabilityZoneFilter', 'RamFilter', 'DiskFilter', 'ComputeFilter', 'ImagePropertiesFilter', 'ServerGroupAntiAffinityFilter', 'ServerGroupAffinityFilter']
+  NovaSchedulerMaxAttempts: 30
   NeutronDhcpAgentsPerNetwork: 2
   HeatConvergenceEngine: false
   HeatMaxResourcesPerStack: -1

puppet/services/nova-scheduler.yaml

@@ -41,6 +41,14 @@ parameters:
       An array of filters used by Nova to filter a node.These filters will be
       applied in the order they are listed, so place your most restrictive
       filters first to make the filtering process more efficient.
+  NovaSchedulerMaxAttempts:
+    type: number
+    default: 3
+    description: >
+     Maximum number of attempts the scheduler will make when deploying the
+     instance. You should keep it greater or equal to the number of bare
+     metal nodes you expect to deploy at once to work around potential race
+     conditions when scheduling.
   MonitoringSubscriptionNovaScheduler:
     default: 'overcloud-nova-scheduler'
     type: string
@@ -84,6 +92,7 @@ outputs:
           - nova::ram_allocation_ratio: '1.0'
             nova::scheduler::filter::scheduler_available_filters: {get_param: NovaSchedulerAvailableFilters}
             nova::scheduler::filter::scheduler_default_filters: {get_param: NovaSchedulerDefaultFilters}
+            nova::scheduler::filter::scheduler_max_attempts: {get_param: NovaSchedulerMaxAttempts}
             nova::scheduler::discover_hosts_in_cells_interval: {get_param: NovaSchedulerDiscoverHostsInCellsInterval}
       step_config: |
         include tripleo::profile::base::nova::scheduler