docs/control-plane-algorithm.md - incubator-myriad - Git at Google

 # Control plane algorithm for rebalancing cluster capacity

 _This is a working draft_

 Notes:
 - Each registered YARN ResourceManager will have a minimum quota associated with them. Quota can be expressed in terms of CPU or Memory. OR Minimum number of NodeManagers which are of profile X or higher.
 - Myriad will monitor the registered ResourceManagers to determine if the ResourceManager needs more resources or if the ResourceManager have excess unused resources. And, then it will use this information to flex-up or flex-down the NodeManager, either horizontall or vertically.
 - When making a decision to flex-down NodeManagers, algorithm will take into consideration the kind of containers that are currently running under the chosen NodeManager.
   - If NodeManager is running a AppMaster container, it will be skipped, as killing it will lead to a killing of all it's child containers. Although, this needs to be reconsidered once [YARN-1489](https://issues.apache.org/jira/browse/YARN-1489) gets resolved.
   - A NodeManger should be chosen for flex-down, if reconfiguring and restarting it has minimum impact compared to other NodeManagers. This strategy can be reconsidered once [YARN-1336](https://issues.apache.org/jira/browse/YARN-1336) gets resolved.

 ---
 <sub>
 Licensed to the Apache Software Foundation (ASF) under one
 or more contributor license agreements.  See the NOTICE file
 distributed with this work for additional information
 regarding copyright ownership.  The ASF 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

 <sub>
   http://www.apache.org/licenses/LICENSE-2.0

 <sub>
 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.
	# Control plane algorithm for rebalancing cluster capacity

	_This is a working draft_

	Notes:
	- Each registered YARN ResourceManager will have a minimum quota associated with them. Quota can be expressed in terms of CPU or Memory. OR Minimum number of NodeManagers which are of profile X or higher.
	- Myriad will monitor the registered ResourceManagers to determine if the ResourceManager needs more resources or if the ResourceManager have excess unused resources. And, then it will use this information to flex-up or flex-down the NodeManager, either horizontall or vertically.
	- When making a decision to flex-down NodeManagers, algorithm will take into consideration the kind of containers that are currently running under the chosen NodeManager.
	- If NodeManager is running a AppMaster container, it will be skipped, as killing it will lead to a killing of all it's child containers. Although, this needs to be reconsidered once [YARN-1489](https://issues.apache.org/jira/browse/YARN-1489) gets resolved.
	- A NodeManger should be chosen for flex-down, if reconfiguring and restarting it has minimum impact compared to other NodeManagers. This strategy can be reconsidered once [YARN-1336](https://issues.apache.org/jira/browse/YARN-1336) gets resolved.

	---
	<sub>
	Licensed to the Apache Software Foundation (ASF) under one
	or more contributor license agreements. See the NOTICE file
	distributed with this work for additional information
	regarding copyright ownership. The ASF 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

	<sub>
	http://www.apache.org/licenses/LICENSE-2.0

	<sub>
	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.