```ruby
module ManageIQ::Providers::Openstack::InfraManager::Host::Operations
  include ActiveSupport::Concern

  def ironic_fog_node
    connection_options = {:service => "Baremetal"}
    ext_management_system.with_provider_connection(connection_options) do |service|
      service.nodes.get(uid_ems)
    end
  end

  def set_node_maintenance
    ironic_fog_node.set_node_maintenance(:reason=>"CFscaledown")
  end

  def unset_node_maintenance
    ironic_fog_node.unset_node_maintenance
  end

  def external_get_node_maintenance
    ironic_fog_node.maintenance
  end
end
```

Use task queue for set/unset node maintenance
user
```ruby
module ManageIQ::Providers::Openstack::InfraManager::Host::Operations
  include ActiveSupport::Concern

  def ironic_fog_node
    connection_options = {:service => "Baremetal"}
    ext_management_system.with_provider_connection(connection_options) do |service|
      service.nodes.get(uid_ems)
    end
  end

  def set_node_maintenance_queue(userid)
    task_opts = {
      :action => "setting node maintenance on Host for user #{userid}",
      :userid => userid
    }
    queue_opts = {
      :class_name  => self.class.name,
      :method_name => 'set_node_maintenance',
      :instance_id => id,
      :role        => 'ems_operations',
      :zone        => ext_management_system.my_zone,
      :args        => []
    }
    MiqTask.generic_action_with_callback(task_opts, queue_opts)
  end

  def set_node_maintenance
    ironic_fog_node.set_node_maintenance(:reason=>"CFscaledown")
  end

  def unset_node_maintenance_queue(userid)
    task_opts = {
      :action => "unsetting node maintenance on Host for user #{userid}",
      :userid => userid
    }
    queue_opts = {
      :class_name  => self.class.name,
      :method_name => 'unset_node_maintenance',
      :instance_id => id,
      :role        => 'ems_operations',
      :zone        => ext_management_system.my_zone,
      :args        => []
    }
    MiqTask.generic_action_with_callback(task_opts, queue_opts)
  end

  def unset_node_maintenance
    ironic_fog_node.unset_node_maintenance
  end

  def external_get_node_maintenance
    ironic_fog_node.maintenance
  end
end
```
assistant