HADOOP-13932. Fix indefinite article in comments (Contributed by LiXin Ge via Daniel Templeton)
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Daniel Templeton
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@ -41,7 +41,7 @@
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import org.apache.hadoop.io.IOUtils;
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/**
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* Inspects a FSImage storage directory in the "old" (pre-HDFS-1073) format.
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* Inspects an FSImage storage directory in the "old" (pre-HDFS-1073) format.
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* This format has the following data files:
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* - fsimage
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* - fsimage.ckpt (when checkpoint is being uploaded)
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@ -65,7 +65,7 @@ Note that rolling upgrade is supported only from Hadoop-2.4.0 onwards.
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### Upgrade without Downtime
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In a HA cluster, there are two or more *NameNodes (NNs)*, many *DataNodes (DNs)*,
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In an HA cluster, there are two or more *NameNodes (NNs)*, many *DataNodes (DNs)*,
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a few *JournalNodes (JNs)* and a few *ZooKeeperNodes (ZKNs)*.
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*JNs* is relatively stable and does not require upgrade when upgrading HDFS in most of the cases.
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In the rolling upgrade procedure described here,
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@ -76,7 +76,7 @@ Upgrading *JNs* and *ZKNs* may incur cluster downtime.
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Suppose there are two namenodes *NN1* and *NN2*,
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where *NN1* and *NN2* are respectively in active and standby states.
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The following are the steps for upgrading a HA cluster:
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The following are the steps for upgrading an HA cluster:
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1. Prepare Rolling Upgrade
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1. Run "[`hdfs dfsadmin -rollingUpgrade prepare`](#dfsadmin_-rollingUpgrade)"
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@ -133,7 +133,7 @@ However, datanodes can still be upgraded in a rolling manner.
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In a non-HA cluster, there are a *NameNode (NN)*, a *SecondaryNameNode (SNN)*
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and many *DataNodes (DNs)*.
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The procedure for upgrading a non-HA cluster is similar to upgrading a HA cluster
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The procedure for upgrading a non-HA cluster is similar to upgrading an HA cluster
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except that Step 2 "Upgrade Active and Standby *NNs*" is changed to below:
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* Upgrade *NN* and *SNN*
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@ -175,7 +175,7 @@ A newer release is downgradable to the pre-upgrade release
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only if both the namenode layout version and the datanode layout version
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are not changed between these two releases.
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In a HA cluster,
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In an HA cluster,
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when a rolling upgrade from an old software release to a new software release is in progress,
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it is possible to downgrade, in a rolling fashion, the upgraded machines back to the old software release.
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Same as before, suppose *NN1* and *NN2* are respectively in active and standby states.
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@ -76,7 +76,7 @@ libdhfs is thread safe.
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* Concurrency and Hadoop FS "handles"
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The Hadoop FS implementation includes a FS handle cache which
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The Hadoop FS implementation includes an FS handle cache which
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caches based on the URI of the namenode along with the user
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connecting. So, all calls to `hdfsConnect` will return the same
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handle but calls to `hdfsConnectAsUser` with different users will
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@ -9801,7 +9801,7 @@
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<param name="defaultPort" type="int"/>
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<doc>
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<![CDATA[Get the socket address for <code>name</code> property as a
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<code>InetSocketAddress</code>. On a HA cluster,
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<code>InetSocketAddress</code>. On an HA cluster,
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this fetches the address corresponding to the RM identified by
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{@link #RM_HA_ID}.
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@param name property name.
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@ -9416,7 +9416,7 @@
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<param name="defaultPort" type="int"/>
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<doc>
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<![CDATA[Get the socket address for <code>name</code> property as a
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<code>InetSocketAddress</code>. On a HA cluster,
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<code>InetSocketAddress</code>. On an HA cluster,
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this fetches the address corresponding to the RM identified by
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{@link #RM_HA_ID}.
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@param name property name.
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@ -208,7 +208,7 @@ public static String getRMHAId(Configuration conf) {
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@VisibleForTesting
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static String getNeedToSetValueMessage(String confKey) {
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return confKey + " needs to be set in a HA configuration.";
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return confKey + " needs to be set in an HA configuration.";
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}
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@VisibleForTesting
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@ -223,7 +223,7 @@ static String getRMHAIdNeedToBeIncludedMessage(String ids,
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String rmId) {
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return YarnConfiguration.RM_HA_IDS + "("
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+ ids + ") need to contain " + YarnConfiguration.RM_HA_ID + "("
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+ rmId + ") in a HA configuration.";
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+ rmId + ") in an HA configuration.";
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}
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@VisibleForTesting
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@ -2767,7 +2767,7 @@ public static List<String> getServiceAddressConfKeys(Configuration conf) {
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/**
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* Get the socket address for <code>name</code> property as a
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* <code>InetSocketAddress</code>. On a HA cluster,
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* <code>InetSocketAddress</code>. On an HA cluster,
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* this fetches the address corresponding to the RM identified by
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* {@link #RM_HA_ID}.
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* @param name property name.
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@ -441,7 +441,7 @@
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<property>
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<description>Host:Port of the ZooKeeper server to be used by the RM. This
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must be supplied when using the ZooKeeper based implementation of the
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RM state store and/or embedded automatic failover in a HA setting.
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RM state store and/or embedded automatic failover in an HA setting.
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</description>
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<name>yarn.resourcemanager.zk-address</name>
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<!--value>127.0.0.1:2181</value-->
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@ -490,7 +490,7 @@
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<property>
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<description>
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ACLs to be used for the root znode when using ZKRMStateStore in a HA
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ACLs to be used for the root znode when using ZKRMStateStore in an HA
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scenario for fencing.
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ZKRMStateStore supports implicit fencing to allow a single
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@ -606,7 +606,7 @@
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</property>
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<property>
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<description>Name of the cluster. In a HA setting,
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<description>Name of the cluster. In an HA setting,
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this is used to ensure the RM participates in leader
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election for this cluster and ensures it does not affect
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other clusters</description>
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@ -2188,7 +2188,7 @@
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<property>
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<name>yarn.timeline-service.client.fd-retain-secs</name>
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<description>
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How long the ATS v1.5 writer will keep a FSStream open.
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How long the ATS v1.5 writer will keep an FSStream open.
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If this fsstream does not write anything for this configured time,
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it will be close.
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</description>
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@ -740,7 +740,7 @@ T runWithRetries() throws Exception {
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try {
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return run();
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} catch (IOException e) {
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LOG.info("Exception while executing a FS operation.", e);
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LOG.info("Exception while executing an FS operation.", e);
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if (++retry > fsNumRetries) {
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LOG.info("Maxed out FS retries. Giving up!");
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throw e;
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@ -200,7 +200,7 @@ static FSQueueMetrics forQueue(String queueName, Queue parent,
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* @param parent parent queue
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* @param enableUserMetrics if user metrics is needed
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* @param conf configuration
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* @return a FSQueueMetrics object
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* @return an FSQueueMetrics object
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*/
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@VisibleForTesting
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public synchronized
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@ -385,7 +385,7 @@ public File getTestWorkDir() {
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}
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/**
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* In a HA cluster, go through all the RMs and find the Active RM. In a
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* In an HA cluster, go through all the RMs and find the Active RM. In a
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* non-HA cluster, return the index of the only RM.
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*
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* @return index of the active RM or -1 if none of them turn active
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