Bad : The hostname and canonical name for this host are not consistent when checked from a Java proc

Good evening. This message I receive after add two new hosts to the hadoop cluser.

Tehnical info:

Nodes - Debian GNU/Linux 8.9 (jessie)
cloudera-manager-agent 5.13.0-1.cm5130.p0.55~jessie-cm5 amd64
cloudera-manager-daemons 5.13.0-1.cm5130.p0.55~jessie-cm5 all

Earlier we add nodes using web interface. But this 2 nodes was added by hand:

1. Add repo cloudera

2. Install packages from repo

3. Configure /etc/cloudera-scm-agent/config.ini:

server_host=hadoop-server.test.com

After start clouder agents, I saw tho strangeness In cloudera web interface:

1. All Hosts - my new host - CDH Version is None

2. Error from topic: "The hostname and canonical name for this host are not consistent when checked from a Java process."

I dont know is connected to each other this issues or not.

I try resolve second issue:

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

regensburg.test.com 1.1.1.1

This command use from /etc/cloudera-scm-agent/config.ini file. Response is valid - A indicate to this IP and PTR indicate to domain name.

But, from internet space I found this command and it return other response:

java -classpath /usr/share/cmf/lib/agent-5.*.jar com.cloudera.cmon.agent.DnsTest
{"status": "0", "ip": "1.1.1.1", "hostname": "regensburg", "canonicalname": "regensburg.test.com", "localhostDuration": "4", "canonicalnameDuration": "1" }

Ok, hostname is short.

root@regensburg ~ # hostname
regensburg

root@regensburg ~ # hostname -f
regensburg.test.com

In /etc/hosts we had some records:

1.1.1.1 regensburg.test.com regensburg

Why arise this error? In other nodes we didn't receive this error, some info from working node:

root@berlin ~ # python -c "import socket; print socket.getfqdn(); print socket.gethostbyname(socket.getfqdn())"
berlin.test.com
2.2.2.2

java -classpath /usr/share/cmf/lib/agent-5.*.jar com.cloudera.cmon.agent.DnsTest
{"status": "0", "ip": "2.2.2.2", "hostname": "berlin.test.com", "canonicalname": "berlin.test.com", "localhostDuration": "4", "canonicalnameDuration": "0" }

root@berlin ~ # hostname
berlin

root@berlin ~ # hostname -f
berlin.test.com

root@berlin ~ # cat /etc/hosts | grep berli
2.2.2.2 berlin.test.com berlin

root@berlin ~ # dpkg -l | grep clouder
ii  cloudera-manager-agent                5.13.0-1.cm5130.p0.55~jessie-cm5   amd64        The Cloudera Manager Agent
ii  cloudera-manager-daemons              5.13.0-1.cm5130.p0.55~jessie-cm5   all          Provides daemons for monitoring Hadoop and related tools.

From com.cloudera.cmon.agent.DnsTest  on all other nodes we receive FQDN hostname, but on this new - short hostname.