The hostname and canonical name for this host are not consistent

[#1]

Hi All,

When I added a new node in cloudera cluster, The node went to bad health and shows error message like "The hostname and canonical name for this host are not consistent when checked from a Java process" Can any one help us to fix this issue.

Thanks,

Sathishkumar M

[#2 · Accepted solution]

If you're running Red Hat or CenOS, ensure the /etc/sysconfig/network file
has the HOSTNAME field with the FQDN, not just the host name.

HOSTNAME=server1.example.com (good)
HOSTNAME=server1 (bad)

Edit this and reboot the host. Just restarting network services might not
work. Then let us know if the error still continues to be logged.

[#3 · Accepted solution]

If you're running Red Hat or CenOS, ensure the /etc/sysconfig/network file
has the HOSTNAME field with the FQDN, not just the host name.

HOSTNAME=server1.example.com (good)
HOSTNAME=server1 (bad)

Edit this and reboot the host. Just restarting network services might not
work. Then let us know if the error still continues to be logged.

[#4]

Thanks Gautam, It  is working. 

But, Other nodes in the same cluster dont have this FQDN in that path /etc/sysconfig/network and those are working fine.Is there any specific reason?

[#5 · Accepted solution]

That is hard to say. Please run this python one-liner on a host where you
don't get complaints and on the host you just fixed. Do they look similar?

# python -c "import socket; print socket.getfqdn(); print
socket.gethostbyname(socket.getfqdn())"

[#6]

Yes,The onliner diplaying the FQDN in both the nodes.  But we tried after removing that FQDN in /etc/sysconfig/network file also and we got the same output.

[#7]

Just editing the entry won't suffice. Changes to that file need a reboot to
take effect.

[#8]

Thanks Gautam for your reply. We checked only after the reboot.

[#9]

From what I understand, you have some hosts with HOSTNAME=server1 and some with HOSTNAME=server1.example.com. CM does not complain about all hosts which have HOSTNAME=server1. Is this right?

Are you able to provide the python script output from both types of hosts? What OS are these hosts running?

[#10]

Network file for that node which is in bad health before change 

cat /etc/sysconfig/network

NETWORKING=yes
HOSTNAME=node10

Output of Python code

python -c "import socket; print socket.getfqdn(); print
socket.gethostbyname(socket.getfqdn())"

node10.cluster1.com

Network file for that node which is already in good health

cat /etc/sysconfig/network

python -c "import socket; print socket.getfqdn(); print
socket.gethostbyname(socket.getfqdn())"

node6.cluster1.com

Thanks

Sathishkumar M

[#11]

Satish, I am failing to see the problem here. Maybe I'm missing something obvious?

You were getting warnings for node10 earlier but don't any more. Does node6 have "HOSTNAME=node6" and still doesn't generate warnings?