How to fetch active HBase Master node via zkCli command ?

[#1]

Hi,

I want to get the current active HBaseMaster from Zookeeper under znode /hbase-secure/master via zkCli.sh commandline call.

The output is almost fine, but the nodename is somehow screwed up, so that I cannot use it for comparisons later on =>

#>/usr/hdp/current/zookeeper-client/bin/zkCli.sh -server 01876.something.corp,01874.something.corp,02878.something.corp get /hbase-secure/master
Connecting to 01876.something.corp,01874.something.corp,02878.something.corp
WATCHER::
WatchedEvent state:SyncConnected type:None path:null
WATCHER::
WatchedEvent state:SaslAuthenticated type:None path:null
�master:16000��O�;��PBUF
'
2878.something.corp�}�����*�}
cZxid = 0x6a00019c8a
ctime = Fri Jun 17 14:59:21 CEST 2016
mZxid = 0x6a00019c8a
mtime = Fri Jun 17 14:59:21 CEST 2016
pZxid = 0x6a00019c8a
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x1555727df0a001c
dataLength = 75
numChildren = 0

Any hint how to get the correct nodename of the current active HBase Master via commandline ?!?!

Thanks, Gerd

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HDP 2.3.4.7, HBase HA , kerberized

[#2]

Hi Gerd,

You found the right ZNode used for having one and only one active HBase master at one time. The reason it's "screwed" up is that you're actually seeing a serialized data structure. The contents of that znode is a serialized instance of the org.apache.hadoop.hbase.protobuf.generated.ZooKeeperProtos.Master protocol buffer class.

I'm not seeing anything in the HBase shell yet which would be helpful.

[#3]

Many thanks for the xplanation @Josh Elser

I'll use status 'detailed' + some grep'ing around as mentioned by @Enis

[#4]

Actually, looks like we might bundle a script you can call for this:

/usr/hdp/current/hbase-client/bin/hbase-jruby /usr/hdp/current/hbase-client/bin/get-active-master.rb

Not sure what the availability of this script is across older versions of HDP.

[#5 · Accepted solution]

In newer versions of the HBase, you can use

	status 'detailed'

which will print the active master, backup masters as well as regionservers.

[#6]

Hi @Enis,

thanks for this hint. I'll use that in a way like

echo "status 'detailed'" >hbase.command
echo "exit" >> hbase.command
hbase shell -n hbase.command
=> and then further process the output with bash builtins

Thanks, Gerd