PawasChhokra commented on a change in pull request #1446: URL: https://github.com/apache/samza/pull/1446#discussion_r539866505
########## File path: samza-core/src/main/java/org/apache/samza/clustermanager/FaultDomainManager.java ########## @@ -0,0 +1,71 @@ +/* + * 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 + * + * 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 org.apache.samza.clustermanager; + +import java.util.Map; +import java.util.Set; + +/** + * This interface gets fault domain information of different nodes from the cluster manager (Yarn/Kubernetes/etc.). + * It also provides other functionality like exposing all the available fault domains, checking if two hosts belong to + * the same fault domain, and getting the valid fault domains that a standby container can be placed on. + */ +public interface FaultDomainManager { + + /** + * This method returns all the fault domain values in a cluster for RUNNING nodes. + * @return a set of {@link FaultDomain}s + */ + Set<FaultDomain> getAllFaultDomains(); + + /** + * This method returns the fault domain a particular node resides on. + * @param host the host + * @return the {@link FaultDomain} + */ + FaultDomain getFaultDomainOfNode(String host); + + /** + * This method checks if the two hostnames provided reside on the same fault domain. + * @param host1 hostname + * @param host2 hostname + * @return true if the hosts exist on the same fault domain + */ + boolean checkHostsOnSameFaultDomain(String host1, String host2); + + /** + * This method gets the set of fault domains that the given active container's corresponding standby can be placed on. + * @param host The hostname of the active container + * @return the set of fault domains on which this active container's standby can be scheduled Review comment: 1. The purpose of this method is to find a list of fault domains that the host's (which is meant to be the active container) standby can be placed on. What are you suggesting to change it to in this case, since the function is active and standby container specific? 2. Any rack about to undergo maintenance will be marked unhealthy. Hence, even if we have that rack in our local cache, Yarn will not return a host to us on an unhealthy rack. 3. Caught up with Manasa and leaving this aside for now. 4. Done. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected]
