--Marking Datanode Dead
2 * dfs.namenode.heartbeat.recheck-interval + 10 * dfs.heartbeat.interval
dfs.heartbeat.interval - defaults to 3 seconds
dfs.namenode.heartbeat.recheck-interval - defaults to 300,000 milliseconds = 300 seconds
2 * 300 seconds + 10 * 3 seconds = 630 seconds (10 minutes and 30 seconds)
--To commission or decommission datanodes
sudo vi /etc/hadoop/conf/hdfs-site.xml
<property>
<name>dfs.hosts</name>
<value>/etc/hadoop/conf/include</value>
</property>
<property>
<name>dfs.hosts.exclude</name>
<value>/etc/hadoop/conf/exclude</value>
</property>
sudo vi /etc/hadoop/conf/include
sudo vi /etc/hadoop/conf/exclude
--After include/exclude changes, refresh nodes for changes to take effect
hdfs dfsadmin -refreshNodes
http://ec2-10-10-10-10.compute-1.amazonaws.com:50070/dfshealth.html
--To commission or decommission nodemanagers
sudo vi /etc/hadoop/conf/yarn-site.xml
<property>
<name>yarn.resourcemanager.nodes.include-path</name>
<value>/etc/hadoop/conf/include</value>
</property>
<property>
<name>yarn.resourcemanager.nodes.exclude-path</name>
<value>/etc/hadoop/conf/exclude</value>
</property>
--After include/exclude changes, refresh nodes for changes to take effect
yarn rmadmin -refreshNodes
--Support graceful decommission of nodemanager
https://issues.apache.org/jira/browse/YARN-914
