Automatic Failover not working in Hadoop

Question

I'm trying to build a 3 node cluster (2 Namenode(nn1,nn2) and 1 datanode(dn1)) .Using Namenode WEBUI, I'm able to view that nn1 is active and nn2 is standby. however, when I kill the active nn1, standby nn2 is not going active. Please help me what am I doing wrong or what needs to be modified

nn1 /etc/hosts

127.0.0.1 localhost
192.168.10.153 nn1
192.168.10.154 dn1
192.168.10.155 nn2

nn2 /etc/hosts

127.0.0.1       localhost nn2
127.0.1.1       ubuntu

    # The following lines are desirable for IPv6 capable hosts
    ::1     ip6-localhost ip6-loopback
    fe00::0 ip6-localnet
    ff00::0 ip6-mcastprefix
    ff02::1 ip6-allnodes
    ff02::2 ip6-allrouters

core-site.xml (nn1,nn2)

<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://192.168.10.153:8020</value>
</property>

<property>
<name>dfs.journalnode.edits.dir</name>
<value>/usr/local/hadoop/hdfs/data/jn</value>
</property>
 <property>
 <name>ha.zookeeper.quorum</name>
 <value>192.168.10.153:2181,192.168.10.155:2181,192.168.10.154:2181</value>
 </property>

</configuration>

hdfs-site.xml(nn1,nn2,dn1)

<property>
 <name>dfs.replication</name>
 <value>1</value>
 </property>
 <property>
 <name>dfs.permissions</name>
 <value>false</value>
 </property>
 <property>
 <name>dfs.nameservices</name>
 <value>ha-cluster</value>
 </property>
 <property>
 <name>dfs.ha.namenodes.ha-cluster</name>
 <value>nn1,nn2</value>
 </property>
 <property>
 <name>dfs.namenode.rpc-address.ha-cluster.nn1</name>
 <value>192.168.10.153:9000</value>
 </property>
 <property>
 <name>dfs.namenode.rpc-address.ha-cluster.nn2</name>
 <value>192.168.10.155:9000</value>
 </property>
 <property>/usr/local/hadoop/hdfs/datanode</value>
 <name>dfs.namenode.http-address.ha-cluster.nn1</name>
 <value>192.168.10.153:50070</value>
 </property>
 <property>
 <name>dfs.namenode.http-address.ha-cluster.nn2</name>
 <value>192.168.10.155:50070</value>
 </property>
 <property>
 <name>dfs.namenode.shared.edits.dir</name>
 <value>qjournal://192.168.10.153:8485;192.168.10.155:8485;192.168.10.154:8485/ha-cluster</value>
 </property>
 <property>
 <name>dfs.client.failover.proxy.provider.ha-cluster</name>
 <value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
 </property>
 <property>
 <name>dfs.ha.automatic-failover.enabled</name>
 <value>true</value>
 </property>
 <property>
 <name>ha.zookeeper.quorum</name>
 <value>192.168.10.153:2181,192.168.10.155:2181,192.168.10.154:2181</value>
 </property>

<property>
 <name>dfs.ha.fencing.methods</name>
 <value>sshfence</value>
 </property>
 <property>
 <name>dfs.ha.fencing.ssh.private-key-files</name>
 <value>/home/ci/.ssh/id_rsa</value></property></configuration>

LOGS :(zkfc nn1,nn2)(namenode nn1,nn2) on stopping nn1(active node) https://pastebin.com/bWvfnanQ

Answer 1

Your mentioning <IP>:<port> for fs.defaultFS in core-site.xml for a HA cluster. So when shutting down your active namenode, it doesn't know where to redirect.

Choose logical name for a nameservice, for example “mycluster”.

Then change in hdfs-site.xml as well, dfs.namenode.http-address.[nameservice ID].[name node ID] - the fully-qualified HTTP address for each NameNode to listen on

In your case, you have to give

core-site.xml

<property>
<name>fs.defaultFS</name>
<value>hdfs://myCluster</value>
</property>

hdfs-site.xml

 <property>
 <name>dfs.namenode.rpc-address.myCluster.nn1</name>
 <value>192.168.10.153:9000</value>
 </property>

Read the manual clearly https://hadoop.apache.org/docs/r2.7.2/hadoop-project-dist/hadoop-hdfs/HDFSHighAvailabilityWithQJM.html

Hope this will help you.

Answer 2

You have to look fencing for automatic failover

https://stackoverflow.com/a/27272565/3496666

https://hadoop.apache.org/docs/r2.7.2/hadoop-project-dist/hadoop-hdfs/HDFSHighAvailabilityWithQJM.html