YARN-5720. Update document for "rmadmin -replaceLabelOnNode". Contributred by Tao Jie

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/NodeLabel.md

@@ -89,7 +89,7 @@ Notes:
 ###Add/modify node-to-labels mapping to YARN
 
 * Configuring nodes to labels mapping in **Centralized** NodeLabel setup
-    * Executing ```yarn rmadmin -replaceLabelsOnNode “node1[:port]=label1 node2=label2”```. Added label1 to node1, label2 to node2. If user don’t specify port, it added the label to all ```NodeManagers``` running on the node.
+    * Executing ```yarn rmadmin -replaceLabelsOnNode “node1[:port]=label1 node2=label2” [-failOnUnknownNodes]```. Added label1 to node1, label2 to node2. If user don’t specify port, it adds the label to all ```NodeManagers``` running on the node. If option ```-failOnUnknownNodes``` is set, this command will fail if specified nodes are unknown.
 
 * Configuring nodes to labels mapping in **Distributed** NodeLabel setup
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/YarnCommands.md

@@ -215,7 +215,7 @@ Usage:
      -getGroups [username]
      -addToClusterNodeLabels <"label1(exclusive=true),label2(exclusive=false),label3">
      -removeFromClusterNodeLabels <label1,label2,label3> (label splitted by ",")
-     -replaceLabelsOnNode <"node1[:port]=label1,label2 node2[:port]=label1,label2">
+     -replaceLabelsOnNode <"node1[:port]=label1,label2 node2[:port]=label1,label2"> [-failOnUnknownNodes]
      -directlyAccessNodeLabelStore
      -refreshClusterMaxPriority
      -updateNodeResource [NodeID] [MemSize] [vCores] ([OvercommitTimeout])
@@ -239,7 +239,7 @@ Usage:
 | -getGroups [username] | Get groups the specified user belongs to. |
 | -addToClusterNodeLabels <"label1(exclusive=true),label2(exclusive=false),label3"> | Add to cluster node labels. Default exclusivity is true. |
 | -removeFromClusterNodeLabels <label1,label2,label3> (label splitted by ",") | Remove from cluster node labels. |
-| -replaceLabelsOnNode <"node1[:port]=label1,label2 node2[:port]=label1,label2"> | Replace labels on nodes (please note that we do not support specifying multiple labels on a single host for now.) |
+| -replaceLabelsOnNode <"node1[:port]=label1,label2 node2[:port]=label1,label2"> [-failOnUnknownNodes]| Replace labels on nodes (please note that we do not support specifying multiple labels on a single host for now.) -failOnUnknownNodes is optional, when we set this option, it will fail if specified nodes are unknown.|
 | -directlyAccessNodeLabelStore | This is DEPRECATED, will be removed in future releases. Directly access node label store, with this option, all node label related operations will not connect RM. Instead, they will access/modify stored node labels directly. By default, it is false (access via RM). AND PLEASE NOTE: if you configured yarn.node-labels.fs-store.root-dir to a local directory (instead of NFS or HDFS), this option will only work when the command run on the machine where RM is running. |
 | -refreshClusterMaxPriority | Refresh cluster max priority |
 | -updateNodeResource [NodeID] [MemSize] [vCores] \([OvercommitTimeout]\) | Update resource on specific node. |