I am new to linux and hadoop and I am having the same issue as in this question. I think I understand what is causing it but I don't know how to solve it (Don't know what they mean by "Edit the Hadoop server's configuration file so that it includes its NIC's address."). The other post that they link says that the configuration files should refer to the machine's externally accessible host name. I think I got this right as every hadoop configuration file refers to "master" and the etc/hosts file lists the master by its private IP address. How can I solve this?

Edit: I have 5 nodes: master, slavec, slaved, slavee and slavef all running debian. This is the hosts file in master:

127.0.0.1       master
10.0.1.201      slavec
10.0.1.202      slaved
10.0.1.203      slavee
10.0.1.204      slavef

this is the hosts file in slavec (it looks similar in the other slaves):

10.0.1.200      master
127.0.0.1       slavec
10.0.1.202      slaved
10.0.1.203      slavee
10.0.1.204      slavef

the masters file in master:

master

the slaves file in master:

master
slavec
slaved
slavee
slavef

the masters and slaves file in slavex has only one line: slavex