hadoop configuration and installation

1. Add new users

sudo useradd -m hadoop -s /bin/bash

       add password

sudo passwd hadoop

      Additional permissions

sudo adduser hadoop sudo

     Switch to the hadoop user, when running the sudo command it appears: hadoop is no longer in the sudoers file, this will be reported.

     Solution: switch to the root user, open the /etc/sudoers file, add

hadoop ALL=（ALL：ALL） ALL

    There is an example of a user in the file, and the above command is written like

   Switch to the hadoop directory (the following operations are performed in the hadoop directory, including idea, jdk (copy the environment variables in .bashrc under root to                 

   in the bashrc file in the hadoop directory))

Second, configure password-free login ssh

      Generate ssh public key

ssh-keygen -t rsa

      Install openssh-server (openssh-clients usually come with the system)

sudo apt-get install openssh-server

      Enter the .ssh directory in the directory of the public key (add authorization)

cat id_rsa.pub >> authorized_keys

      give permission

chmod 600 ./authorized_keys

   Run the command: ssh localhost

   出现：sign_and_send_pubkey: signing failed: agent refused operation

   and ask for a password

    Solution:

eval "$(ssh-agent -s)"
ssh-add

  Then run: ssh localhost You can enter without entering a password, and exit can exit ssh