Add Chapter 17 scripts

ch17/dfs_used_metric.sh

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+#!/usr/bin/env bash
+
+dfs_used=$(/opt/hadoop/bin/hdfs dfsadmin -report | \
+  grep -m 1 "DFS Used%" | cut -d ' ' -f 3 | sed 's/%//g')
+
+/usr/local/bin/aws cloudwatch put-metric-data --metric-name DFSUsed \
+  --namespace HadoopClusters --unit Percent --value "$dfs_used" \
+  --dimensions Cluster=MyFirstCluster

ch17/yarn_mem_metric.sh

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+#!/usr/bin/env bash
+
+yarn_mem_used=$(/path/to/yarnmem.sh)
+
+/usr/local/bin/aws cloudwatch put-metric-data --metric-name YarnMemUsage \
+  --namespace HadoopClusters --unit Percent --value "$yarn_mem_used" \
+  --dimensions Cluster=MyFirstCluster

ch17/yarnmem.sh

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+#!/usr/bin/env bash
+
+used_total=0
+available_total=0
+
+for n in $(yarn node -list 2>/dev/null | grep -v Total | grep -v Node-Id | \
+  cut -d ' ' -f 1); do
+  mem="$(yarn node -status "$n" 2>/dev/null | grep 'Memory-' | \
+    cut -d ' ' -f 3 | sed 's/MB//g' | xargs)"
+  used=${mem%% *}
+  available=${mem##* }
+  used_total=$(( used_total + used ))
+  available_total=$(( available_total + available ))
+done
+
+if [[ $available_total == 0 ]]; then
+  echo 0
+else
+  bc <<< "scale=4;($used_total/$available_total)*100"
+fi