Hadoop NameNode JMX REST Query for NameNodeStatus

gistfile1.txt

> curl 'http://172.20.11.177:50070/jmx?qry=Hadoop:service=NameNode,name=NameNodeStatus'
{
  "beans" : [ {
    "name" : "Hadoop:service=NameNode,name=NameNodeStatus",
    "modelerType" : "org.apache.hadoop.hdfs.server.namenode.NameNode",
    "State" : "active",
    "NNRole" : "NameNode",
    "HostAndPort" : "localhost:19000",
    "SecurityEnabled" : false,
    "LastHATransitionTime" : 0
  } ]

# "State" is "initializing", "active", "standby" or "stopping".
# "LastHATransitionTime" is the last time of the last flip from standby to active (or vice versa)