Fixes #36745 - VM is not associated upon host registration

app/controllers/api/v2/registration_controller.rb

@@ -77,6 +77,7 @@ def host
           ActiveRecord::Base.transaction do
             find_host
             prepare_host
+            associate_vm
             setup_host_params
             host_setup_extension
             @template = @host.initial_configuration_template
@@ -121,6 +122,19 @@ def prepare_host
         @host.save!
       end
 
+      def associate_vm
+        if @host.compute_resource
+          associator = ComputeResourceHostAssociator.new(@host.compute_resource)
+          associator.associate_host(@host)
+        else
+          ComputeResource.all.each do |compute_resource|
+            associator = ComputeResourceHostAssociator.new(compute_resource)
+            associator.associate_host(@host)
+            break if @host.uuid
+          end
+        end
+      end
+
       # Extension point for plugins
       def host_setup_extension
       end

app/models/compute_resource.rb

@@ -457,6 +457,19 @@ def associate_by(name, attributes)
       first
   end
 
+  def associated_vm(host)
+    vms(:eager_loading => true).find { |vm| associate_by_host("mac", vm.interfaces.map(&:mac), host) }
+  end
+
+  def associate_by_host(name, attributes, host)
+    attributes = Array.wrap(attributes).map { |mac| Net::Validations.normalize_mac(mac) } if name == 'mac'
+    Host.authorized(:view_hosts, Host).where(:id => host.id).joins(:primary_interface).
+      where(:nics => {:primary => true}).
+      where(ActiveRecord::Base.sanitize_sql("nics.#{name}") => attributes).
+      readonly(false).
+      first
+  end
+
   private
 
   def set_vm_volumes_attributes(vm, vm_attrs)

app/models/compute_resources/foreman/model/ec2.rb

@@ -147,6 +147,10 @@ def associated_host(vm)
       associate_by("ip", [vm.public_ip_address, vm.private_ip_address])
     end
 
+    def associated_vm(host)
+      vms(:eager_loading => true).find { |vm| associate_by_host("ip", [vm.public_ip_address, vm.private_ip_address], host) }
+    end
+
     def user_data_supported?
       true
     end

app/models/compute_resources/foreman/model/openstack.rb

@@ -204,6 +204,10 @@ def associated_host(vm)
       associate_by("ip", [vm.floating_ip_address, vm.private_ip_address].compact)
     end
 
+    def associated_vm(host)
+      vms(:eager_loading => true).find { |vm| associate_by_host("ip", [vm.floating_ip_address, vm.private_ip_address].compact, host) }
+    end
+
     def flavor_name(flavor_ref)
       client.flavors.get(flavor_ref).try(:name)
     end

app/services/compute_resource_host_associator.rb

@@ -15,6 +15,17 @@ def associate_hosts(vms = compute_resource.vms(:eager_loading => true))
     end
   end
 
+  def associate_host(host)
+    vm = compute_resource.associated_vm(host)
+    if vm.present?
+      host.associate!(compute_resource, vm)
+      @hosts << host
+    end
+  rescue StandardError => e
+    @fail_count += 1
+    Foreman::Logging.exception("Could not associate host #{host}", e)
+  end
+
   private
 
   def associate_vm(vm)