io.druid.indexing.overlord.autoscaling.ProvisioningService Maven / Gradle / Ivy
/*
* Licensed to Metamarkets Group Inc. (Metamarkets) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. Metamarkets licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package io.druid.indexing.overlord.autoscaling;
import io.druid.guice.annotations.PublicApi;
import java.io.Closeable;
/**
* The ProvisioningService decides if worker nodes should be provisioned or terminated
* based on the available tasks in the system and the state of the workers in the system.
*
* ProvisioningService is tied to the task runner.
*
* @see ProvisioningStrategy#makeProvisioningService
*/
@PublicApi
public interface ProvisioningService extends Closeable
{
/**
* Should be called from TaskRunner's lifecycle stop
*/
@Override
void close();
/**
* Get any interesting stats related to scaling
*
* @return The ScalingStats or `null` if nothing of interest
*/
ScalingStats getStats();
}