Hadoop single-node starting issue - hadoop

Question

I'm trying to bring up the hadoop standalone server (in aws) by executing
start-dfs.sh file but got the below error
Starting namenodes on [ip-xxx-xx-xxx-xx]
ip-xxx-xx-xxx-xx: Permission denied (publickey).
Starting datanodes
localhost: Permission denied (publickey).
Exception in thread "main" java.lang.UnsupportedClassVersionError: org/apache/hadoop/hdfs/tools/GetConf : Unsupported major.minor version 52.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:808)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:442)
at java.net.URLClassLoader.access$100(URLClassLoader.java:64)
at java.net.URLClassLoader$1.run(URLClassLoader.java:354)
at java.net.URLClassLoader$1.run(URLClassLoader.java:348)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:347)
at java.lang.ClassLoader.loadClass(ClassLoader.java:430)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:323)
at java.lang.ClassLoader.loadClass(ClassLoader.java:363)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:482)
Installed Java version is javac 1.7.0_181
Hadoop is 3.0.3.
Below is the path contents in profile file
export JAVA_HOME=/usr
export PATH=$PATH:$JAVA_HOME/bin
export HADOOP_HOME=/usr/local/hadoop
export PATH=$PATH:$HADOOP_HOME/bin
export HADOOP_CONF_DIR=/usr/local/hadoop/etc/hadoop
#export PATH=$PATH:$HADOOP_CONF_DIR
export SCALA_HOME=/usr/local/scala
export PATH=$PATH:$SCALA_HOME/bin
What is the issue ? is there anything i'm missing?
thanks

Answer 1

ssh-keygen
2.It will ask for folder location where it will copy the keys, I entered /home/hadoop/.ssh/id_rsa
3.it will ask for pass phrase, keep it empty for simplicity.
cat /home/hadoop/.ssh/id_rsa.pub .>> ssh/authorized_keys (To copy the newly generated public key to auth file in your users home/.ssh directory)
ssh localhost should not ask for a password
start-dfs.sh (Now it should work!)