hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/runtime/ContainerRuntime.java

/*
 * *
 *  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.hadoop.yarn.server.nodemanager.containermanager.runtime;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.yarn.server.nodemanager.containermanager.container.Container;

import java.util.Map;

/**
 * An abstraction for various container runtime implementations. Examples
 * include Process Tree, Docker, Appc runtimes etc. These implementations
 * are meant for low-level OS container support - dependencies on
 * higher-level node mananger constructs should be avoided.
 */

@InterfaceAudience.Private
@InterfaceStability.Unstable
public interface ContainerRuntime {
  /**
   * Prepare a container to be ready for launch.
   *
   * @param ctx the {@link ContainerRuntimeContext}
   * @throws ContainerExecutionException if an error occurs while preparing
   * the container
   */
  void prepareContainer(ContainerRuntimeContext ctx)
      throws ContainerExecutionException;

  /**
   * Launch a container.
   *
   * @param ctx the {@link ContainerRuntimeContext}
   * @throws ContainerExecutionException if an error occurs while launching
   * the container
   */
  void launchContainer(ContainerRuntimeContext ctx)
      throws ContainerExecutionException;

  /**
   * Signal a container. Signals may be a request to terminate, a status check,
   * etc.
   *
   * @param ctx the {@link ContainerRuntimeContext}
   * @throws ContainerExecutionException if an error occurs while signaling
   * the container
   */
  void signalContainer(ContainerRuntimeContext ctx)
      throws ContainerExecutionException;

  /**
   * Perform any container cleanup that may be required.
   *
   * @param ctx the {@link ContainerRuntimeContext}
   * @throws ContainerExecutionException if an error occurs while reaping
   * the container
   */
  void reapContainer(ContainerRuntimeContext ctx)
      throws ContainerExecutionException;

  /**
   * Return the host and ip of the container
   *
   * @param container the {@link Container}
   * @throws ContainerExecutionException if an error occurs while getting the ip
   * and hostname
   */
  String[] getIpAndHost(Container container) throws ContainerExecutionException;

  /**
   * Whether to propagate the whitelist of environment variables from the
   * nodemanager environment into the container environment.
   * @param env the container's environment variables
   * @return true if whitelist variables should be propagated, false otherwise
   * @see org.apache.hadoop.yarn.conf.YarnConfiguration#NM_ENV_WHITELIST
   */
  boolean useWhitelistEnv(Map<String, String> env);
}