There are some points to pay attention:
1 change all the configuration file for both master and slave. core-site.xml, mapreduce.xml
2 pay attention to firewall, use sudo ufw status, to check whether there is a firewall.
3 For the namenode format, only performance it in master node. Because slave node is pointing to the master node hdfs url.
4 check java version, operating system version. They have the same version of java otherwise master and slave will synchronise very slowly.
5 Pay attention to ssh, the best way is to ssh-keygen in all nodes, and cat the public key to authorized_key and copy this file to all nodes. Make sure all authorized_keys contains all machines information in all nodes.
6 Make sure the /etc/hosts, delete 127.0.1.1 , this will cause the “getProcolversion….” error.