Spinning Up a Free Hadoop Cluster: Step by Step
Austin Ouyang

I am getting an error when I try an start the Hadoop cluster: This is the error I am getting:

ubuntu@ip-172–31–18–78:~$ $HADOOP_HOME/sbin/start-dfs.sh
Starting namenodes on [ec2–35–161–4–52.us-west-2.compute.amazonaws.com]
ec2–35–161–4–52.us-west-2.compute.amazonaws.com: starting namenode, logging to /usr/local/hadoop/logs/hadoop-ubuntu-namenode-ip-172–31–18–78.out
datanode3_hostname: ssh: Could not resolve hostname datanode3_hostname: Name or service not known
datanode1_hostname: ssh: Could not resolve hostname datanode1_hostname: Name or service not known
datanode2_hostname: ssh: Could not resolve hostname datanode2_hostname: Name or service not known

I am able to access each through ssh — so I am not sure what is going wrong. Here is my /etc/hosts file all allnodes: localhost
ec2–35–162–3–52.us-west-2.compute.amazonaws.com namenode_hostname
ec2–35–163–208–31.us-west-2.compute.amazonaws.com datanode1_hostname
ec2–34–162–153–30.us-west-2.compute.amazonaws.com datanode2_hostname
ec2–40–161–36–35.us-west-2.compute.amazonaws.com datanode3_hostname

# 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
ff02::3 ip6-allhosts
“/etc/hosts” 14L, 494C

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