Only run kube_monitor threads on master MiqServer

On podified there are multiple miq_server instances but only one
"master".  All miq_servers run on the same kubernetes cluster and thus
only have to run one set of monitor_pods/monitor_deployments threads to
update the global current_pods/current_deployments hashes.

app/models/miq_server/worker_management/kubernetes.rb

@@ -14,15 +14,28 @@ def sync_monitor
   end
 
   def sync_from_system
+    # All miq_server instances have to reside on the same Kubernetes cluster, so
+    # we only have to sync the list of pods and deployments once
+    return unless my_server.is_master?
+
     ensure_kube_monitors_started
-    cleanup_orphaned_worker_rows
-    sync_deployment_settings
   end
 
   def enough_resource_to_start_worker?(_worker_class)
     true
   end
 
+  def sync_workers
+    # Before syncing the workers check for any orphaned worker rows that don't have
+    # a current pod and delete them
+    cleanup_orphaned_worker_rows
+
+    # Update worker deployments with updated settings such as cpu/memory limits
+    sync_deployment_settings
+
+    super
+  end
+
   def cleanup_orphaned_worker_rows
     unless current_pods.empty?
       orphaned_rows = podified_miq_workers.where.not(:system_uid => current_pods.keys)
@@ -131,6 +144,8 @@ def ensure_kube_monitors_started
   end
 
   def delete_failed_deployments
+    return unless my_server.is_master?
+
     failed_deployments.each do |failed|
       orchestrator.delete_deployment(failed)
     end

app/models/miq_server/worker_management/monitor.rb

@@ -96,6 +96,10 @@ def do_system_limit_exceeded
     end
   end
 
+  def sync_from_system
+    raise NotImplementedError, "Must be implemented in a subclass"
+  end
+
   def sync_monitor
     @last_sync ||= Time.now.utc
     sync_interval         = @worker_monitor_settings[:sync_interval] || 30.minutes

spec/models/miq_server/worker_management/kubernetes_spec.rb

@@ -1,7 +1,7 @@
 require 'recursive-open-struct'
 
 RSpec.describe MiqServer::WorkerManagement::Kubernetes do
-  let(:server)          { EvmSpecHelper.create_guid_miq_server_zone.second }
+  let(:server)          { EvmSpecHelper.local_miq_server(:is_master => true) }
   let(:orchestrator)    { double("ContainerOrchestrator") }
   let(:deployment_name) { '1-generic-79bb8b8bb5-8ggbg' }
   let(:pod_label)       { '1-generic' }
@@ -111,7 +111,6 @@
     context "#ensure_kube_monitors_started" do
       it "podified, ensures pod monitor started and orphaned rows are removed" do
         expect(server.worker_manager).to receive(:ensure_kube_monitors_started)
-        expect(server.worker_manager).to receive(:cleanup_orphaned_worker_rows)
         server.worker_manager.sync_from_system
       end
     end