question Re: The hostname and canonical name for this host are not consistent in Support Questions

The hostname and canonical name for this host are not consistent

sathishkumar — Mon, 29 Sep 2014 07:52:43 GMT

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

Re: The hostname and canonical name for this host are not consistent

GautamG — Mon, 29 Sep 2014 07:58:15 GMT

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.

Re: The hostname and canonical name for this host are not consistent

sathishkumar — Mon, 29 Sep 2014 08:14:41 GMT

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?

Re: The hostname and canonical name for this host are not consistent

GautamG — Mon, 29 Sep 2014 08:23:15 GMT

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())"

Re: The hostname and canonical name for this host are not consistent

sathishkumar — Mon, 29 Sep 2014 09:21:23 GMT

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.

Re: The hostname and canonical name for this host are not consistent

GautamG — Mon, 29 Sep 2014 09:23:15 GMT

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

Re: The hostname and canonical name for this host are not consistent

sathishkumar — Mon, 29 Sep 2014 11:55:52 GMT

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

Re: The hostname and canonical name for this host are not consistent

GautamG — Tue, 30 Sep 2014 02:50:50 GMT

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?

Re: The hostname and canonical name for this host are not consistent

sathishkumar — Tue, 30 Sep 2014 05:15:19 GMT

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

Re: The hostname and canonical name for this host are not consistent

GautamG — Wed, 01 Oct 2014 11:16:09 GMT

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?

Re: The hostname and canonical name for this host are not consistent

devarajan — Wed, 08 Feb 2017 02:34:10 GMT

Hi , I also had the same issue in RHEL 7 . As suggested I modified the "HOSTNAME" attribute in /etc/sysconfig/network file to FQDN. Following that I also modified the hostname to FQDN using the following command:

hostnamectl set-hostname "<your hostname FQDN>" --static

Followed by this I restarted cloudera-scm-agent . This worked for me , there were no more critical warnings on hostname and canonical hostname .

Re: The hostname and canonical name for this host are not consistent

chrisk23 — Wed, 21 Jun 2017 16:14:43 GMT

The python command should be all one line, or use a "\" to continue on a new line.

For example:

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

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

Re: The hostname and canonical name for this host are not consistent

rampo — Mon, 03 Jul 2017 21:42:34 GMT

I am having same problem here.

I used to install Cloudera Manager on Centos 7 with no issues.

But in Centos 6(since impala is not supported on Centos 7, had to try Centos 6), getting this error on all hosts.

My /etc/sysconfig/network file is like this:

$ cat /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=cixa.c.gib-data.internal

I rebooted all hosts after setting HOSTNAME in /etc/sysconfig/network file.

All other nodes share same configuration.

Host inspection gives no warning.

In host status, this error message is shown:

"The hostname and canonical name for this host are not consistent when checked from a Java process"

$ python -c "import socket; print socket.getfqdn(); print socket.gethostbyname(socket.getfqdn())"
cixa.c.gib-data.internal
10.128.0.2

All hosts answer correctly to nslookup and host commands.

All hosts can shh and ping to all others with FQDN.

Re: The hostname and canonical name for this host are not consistent

GautamG — Tue, 04 Jul 2017 00:36:43 GMT

rampo wrote:
But in Centos 6(since impala is not supported on Centos 7, had to try Centos 6), getting this error on all hosts.

This is not true, our latest versions of CDH do run on CentOS 7 which means Impala is supported on it as well.

e.g. 5.11.1

https://www.cloudera.com/documentation/enterprise/release-notes/topics/cdh_vd_cdh_download_511.html

Re: The hostname and canonical name for this host are not consistent

rampo — Tue, 04 Jul 2017 08:27:24 GMT

I have installed Cloudera Manager 5.11 on CentOS7. Unfortunately on Parcels page, it says:

Impala is not supported on RHEL 7.

That's the whole reason I fallback to CenOS 6.

Also when I check Impala Parcels on http://archive.cloudera.com/impala/parcels/latest/ I see there is no EL7 parcel.

Here is the complete list of Impala parcels:

IMPALA-2.1.0-1.impala2.0.0.p0.1995-el5.parcel
IMPALA-2.1.0-1.impala2.0.0.p0.1995-el6.parcel
IMPALA-2.1.0-1.impala2.0.0.p0.1995-lucid.parcel
IMPALA-2.1.0-1.impala2.0.0.p0.1995-precise.parcel
IMPALA-2.1.0-1.impala2.0.0.p0.1995-sles11.parcel
IMPALA-2.1.0-1.impala2.0.0.p0.1995-squeeze.parcel

Re: The hostname and canonical name for this host are not consistent

GautamG — Tue, 04 Jul 2017 10:54:01 GMT

@rampo wrote:
Also when I check Impala Parcels on http://archive.cloudera.com/impala/parcels/latest/ I see there is no EL7 parcel.

I'm glad you mentioned the parcel repo. With the latest releases of CDH, Impala is included in the CDH parcel itself and doesn't need a separate repository. The current version of Impala in CDH 5.11.1 is 2.8.0, see this URL: https://www.cloudera.com/documentation/enterprise/release-notes/topics/cdh_vd_cdh_package_tarball_511.html

So this means, if you're able to create a CDH cluster on a bunch of CentOS 7 hosts, you should be able to add the Impala service as well. Please don't add that parcel quoted above as it's not required any longer.

Re: The hostname and canonical name for this host are not consistent

rampo — Tue, 04 Jul 2017 19:19:57 GMT

Thank you @GautamG

I wasn't aware of that until you clearly stated that.

Re: The hostname and canonical name for this host are not consistent

prabhat10 — Mon, 21 May 2018 13:24:43 GMT

error still persists even after restarting

am using centOs 6

[root@instance-1 Admin]# hostname -f
instance-1.c.sacred-evening-197206.internal
[root@instance-1 Admin]# cat /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=instance-1.c.sacred-evening-197206.internal
[root@instance-1 Admin]#

what to do kindly suggest.

Re: The hostname and canonical name for this host are not consistent

bgooley — Mon, 21 May 2018 17:09:21 GMT

hi @prabhat10,

Since this is an old thread, we should make sure you are indeed seeing the same issue that is described.

Please let us know what you are doing when you see the problem and what the problem is.

If you are seeing the message that is in the initial comment of this thread, then to get some more insight, I recommend running the DNSTest manually like this on a cluster host:

(make sure java is in your path or specify the full path to the java file)

# java -classpath /usr/share/cmf/lib/agent-5.*.jar com.cloudera.cmon.agent.DnsTest

The output will be a JSON format file like this:

{"status": "0", "ip": "122.168.100.211", "hostname": "host.example.com", "canonicalname": "host.example.com", "localhostDuration": "4", "canonicalnameDuration": "0" }

This might shed some light on what is going on. I'd check your hosts file or DNS depending on how your host resolution is configured on that host.

Regards,

Ben

Re: The hostname and canonical name for this host are not consistent

prabhat10 — Tue, 22 May 2018 07:23:26 GMT

hello@bgooley

i have run this command

# java -classpath /usr/share/cmf/lib/agent-5.*.jar com.cloudera.cmon.agent.DnsTest

and get this as a output :

[root@instance-1 Admin]# java -classpath /usr/share/cmf/lib/agent-5.*.jar com.cloudera.cmon.agent.DnsTest
{"status": "0", "ip": "10.142.0.4", "hostname": "instance-1", "canonicalname": "instance-1.c.sacred-evening-197206.internal", "localhostDuration": "4", "canonicalnameDuration": "0" }
[root@instance-1 Admin]# cat /etc/sysconfig/network
NETWORKING=yes
HOSTNAME=instance-1.c.sacred-evening-197206.internal

[root@instance-1 Admin]# java -version
openjdk version "1.8.0_171"
OpenJDK Runtime Environment (build 1.8.0_171-b10)
OpenJDK 64-Bit Server VM (build 25.171-b10, mixed mode)
[root@instance-1 Admin]# javac -version
bash: javac: command not found

do i need to run the above command on each hosts and other hosts java is not installed, do i need to instaal it manually. On doing java -version its showing command not found.

[root@instance-1 jdk1.7.0_67-cloudera]# alternatives --display java| grep Current
Current `best' version is /usr/lib/jvm/jre-1.8.0-openjdk.x86_64/bin/java.
[root@instance-1 jdk1.7.0_67-cloudera]# ls /usr/java/
jdk1.7.0_67-cloudera
[root@instance-1 jdk1.7.0_67-cloudera]# ls /usr/java/jdk1.7.0_67-cloudera/
bin lib src.zip
COPYRIGHT LICENSE THIRDPARTYLICENSEREADME-JAVAFX.txt
db man THIRDPARTYLICENSEREADME.txt
include README.html
jre release

kindly suggest!!