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From ctre...@apache.org
Subject hadoop git commit: Revert "YARN-2960. Add documentation for the YARN shared cache."
Date Thu, 05 Oct 2017 18:12:47 GMT
Repository: hadoop
Updated Branches:
  refs/heads/branch-3.0 54a01c28c -> 4b9b66f92

Revert "YARN-2960. Add documentation for the YARN shared cache."

This reverts commit 54a01c28cc153872aa7eed68000ab0ddf010054a.

Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/4b9b66f9
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/4b9b66f9
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/4b9b66f9

Branch: refs/heads/branch-3.0
Commit: 4b9b66f921c671b6426d1bc912cca056cb2532c4
Parents: 54a01c2
Author: Chris Trezzo <ctrezzo@apache.org>
Authored: Thu Oct 5 11:11:02 2017 -0700
Committer: Chris Trezzo <ctrezzo@apache.org>
Committed: Thu Oct 5 11:11:02 2017 -0700

 hadoop-project/src/site/site.xml                |   2 -
 .../src/site/markdown/SharedCache.md            | 168 -------------------
 2 files changed, 170 deletions(-)

diff --git a/hadoop-project/src/site/site.xml b/hadoop-project/src/site/site.xml
index 44551fe..9806f02 100644
--- a/hadoop-project/src/site/site.xml
+++ b/hadoop-project/src/site/site.xml
@@ -141,8 +141,6 @@
       <item name="Graceful Decommission" href="hadoop-yarn/hadoop-yarn-site/GracefulDecommission.html"/>
       <item name="Opportunistic Containers" href="hadoop-yarn/hadoop-yarn-site/OpportunisticContainers.html"/>
       <item name="YARN Federation" href="hadoop-yarn/hadoop-yarn-site/Federation.html"/>
-      <item name="Resource Profiles" href="hadoop-yarn/hadoop-yarn-site/ResourceProfiles.html"/>
-      <item name="Shared Cache" href="hadoop-yarn/hadoop-yarn-site/SharedCache.html"/>
     <menu name="YARN REST APIs" inherit="top">

diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/SharedCache.md
deleted file mode 100644
index ea50e91..0000000
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/SharedCache.md
+++ /dev/null
@@ -1,168 +0,0 @@
-  Licensed 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,
-  See the License for the specific language governing permissions and
-  limitations under the License. See accompanying LICENSE file.
-YARN Shared Cache
-<!-- MACRO{toc|fromDepth=0|toDepth=3} -->
-The YARN Shared Cache provides the facility to upload and manage shared
-application resources to HDFS in a safe and scalable manner. YARN applications
-can leverage resources uploaded by other applications or previous
-runs of the same application without having to reĀ­upload and localize identical files
-multiple times. This will save network resources and reduce YARN application
-startup time.
-Current Status and Future Plans
-Currently the YARN Shared Cache is released and ready to use. The major
-components are implemented and have been deployed in a large-scale
-production setting. There are still some pieces missing (i.e. strong
-authentication). These missing features will be implemented as part of a
-follow-up phase 2 effort. Please see
-[YARN-7282](https://issues.apache.org/jira/browse/YARN-7282) for more information.
-The shared cache feature consists of 4 major components:
-1. The shared cache client.
-2. The HDFS directory that acts as a cache.
-3. The shared cache manager (aka. SCM).
-4. The localization service and uploader.
-### The Shared Cache Client
-YARN application developers and users, should interact with the shared cache using
-the shared cache client. This client is responsible for interacting with the
-shared cache manager, computing the checksum of application resources, and
-claiming application resources in the shared cache. Once an application has claimed
-a resource, it is free to use that resource for the life-cycle of the application.
-Please see the SharedCacheClient.java javadoc for further documentation.
-### The Shared Cache HDFS Directory
-The shared cache HDFS directory stores all of the shared cache resources. It is protected
-by HDFS permissions and is globally readable, but writing is restricted to a trusted user.
-This HDFS directory is only modified by the shared cache manager and the resource uploader
-on the node manager. Resources are spread across a set of subdirectories using the resources's
-### Shared Cache Manager (SCM)
-The shared cache manager is responsible for serving requests from the client and
-managing the contents of the shared cache. It looks after both the meta data as
-well as the persisted resources in HDFS. It is made up of two major components,
-a back end store and a cleaner service. The SCM runs as a separate daemon
-process that can be placed on any node in the cluster. This allows for
-administrators to start/stop/upgrade the SCM without affecting other YARN
-components (i.e. the resource manager or node managers).
-The back end store is responsible for maintaining and persisting metadata about
-the shared cache. This includes the resources in the cache, when a resource was
-last used and a list of applications that are currently using the resource. The
-implementation for the backing store is pluggable and it currently uses an
-in-memory store that recreates its state after a restart.
-The cleaner service maintains the persisted resources in HDFS by ensuring that
-resources that are no longer used are removed from the cache. It scans the
-resources in the cache periodically and evicts resources if they are both stale
-and there are no live applications currently using the application.
-### The Shared Cache uploader and localization
-The shared cache uploader is a service that runs on the node manager and adds
-resources to the shared cache. It is responsible for verifying a resources
-checksum, uploading the resource to HDFS and notifying the shared cache
-manager that a resource has been added to the cache. It is important to note
-that the uploader service is asynchronous from the container launch and does not
-block the startup of a yarn application. In addition adding things to the cache
-is done in a best effort way and does not impact running applications. Once the
-uploader has placed a resource in the shared cache, YARN uses the normal node
-manager localization mechanism to make resources available to the application.
-Developing YARN applications with the Shared Cache
-To support the YARN shared cache, an application must use the shared cache
-client during application submission. The shared cache client returns a
-URL corresponding to a resource if it is in the shared cache. To use the cached
-resource, a YARN application simply uses the cached URL to create a
-LocalResource object and sets setShouldBeUploadedToSharedCache to true during
-application submission.
-For example, here is how you would create a LocalResource using a cached URL:
-String localPathChecksum = sharedCacheClient.getFileChecksum(localPath);
-URL cachedResource = sharedCacheClient.use(appId, localPathChecksum);
-LocalResource resource = LocalResource.newInstance(cachedResource,
-      LocalResourceType.FILE, LocalResourceVisibility.PUBLIC
-      size, timestamp, null, true);
-Administrating the Shared Cache
-### Setting up the shared cache
-An administrator can initially set up the shared cache by following these steps:
-1. Create an HDFS directory for the shared cache (default: /sharedcache).
-2. Set the shared cache directory permissions to 0755.
-3. Ensure that the shared cache directory is owned by the user that runs the
-shared cache manager daemon and the node manager.
-4. In the yarn-site.xml file, set *yarn.sharedcache.enabled* to true and
-*yarn.sharedcache.root-dir* to the directory specified in step 1. For more configuration
-parameters, see the configuration parameters section.
-5. Start the shared cache manager:
-/hadoop/bin/yarn --daemon start sharedcachemanager
-### Configuration parameters
-The configuration parameters can be found in yarn-default.xml and should be set
-in the yarn-site.xml file. Here are a list of configuration parameters and their defaults:
-Name | Description | Default value
---- | --- | ---
-yarn.sharedcache.enabled | Whether the shared cache is enabled | false
-yarn.sharedcache.root-dir | The root directory for the shared cache | /sharedcache
-yarn.sharedcache.nested-level | The level of nested directories before getting to the checksum
directories. It must be non-negative. | 3
-yarn.sharedcache.store.class | The implementation to be used for the SCM store | org.apache.hadoop.yarn.server.sharedcachemanager.store.InMemorySCMStore
-yarn.sharedcache.app-checker.class | The implementation to be used for the SCM app-checker
| org.apache.hadoop.yarn.server.sharedcachemanager.RemoteAppChecker
-yarn.sharedcache.store.in-memory.staleness-period-mins | A resource in the in-memory store
is considered stale if the time since the last reference exceeds the staleness period. This
value is specified in minutes. | 10080
-yarn.sharedcache.store.in-memory.initial-delay-mins | Initial delay before the in-memory
store runs its first check to remove dead initial applications. Specified in minutes. | 10
-yarn.sharedcache.store.in-memory.check-period-mins | The frequency at which the in-memory
store checks to remove dead initial applications. Specified in minutes. | 720
-yarn.sharedcache.admin.address | The address of the admin interface in the SCM (shared cache
manager) |
-yarn.sharedcache.admin.thread-count | The number of threads used to handle SCM admin interface
(1 by default) | 1
-yarn.sharedcache.webapp.address | The address of the web application in the SCM (shared cache
manager) |
-yarn.sharedcache.cleaner.period-mins | The frequency at which a cleaner task runs. Specified
in minutes. | 1440
-yarn.sharedcache.cleaner.initial-delay-mins | Initial delay before the first cleaner task
is scheduled. Specified in minutes. | 10
-yarn.sharedcache.cleaner.resource-sleep-ms | The time to sleep between processing each shared
cache resource. Specified in milliseconds. | 0
-yarn.sharedcache.uploader.server.address | The address of the node manager interface in the
SCM (shared cache manager) |
-yarn.sharedcache.uploader.server.thread-count | The number of threads used to handle shared
cache manager requests from the node manager (50 by default) | 50
-yarn.sharedcache.client-server.address | The address of the client interface in the SCM (shared
cache manager) |
-yarn.sharedcache.client-server.thread-count | The number of threads used to handle shared
cache manager requests from clients (50 by default) | 50
-yarn.sharedcache.checksum.algo.impl | The algorithm used to compute checksums of files (SHA-256
by default) | org.apache.hadoop.yarn.sharedcache.ChecksumSHA256Impl
-yarn.sharedcache.nm.uploader.replication.factor | The replication factor for the node manager
uploader for the shared cache (10 by default) | 10
-yarn.sharedcache.nm.uploader.thread-count | The number of threads used to upload files from
a node manager instance (20 by default) | 20
\ No newline at end of file

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