Errno [111] ! Connexion failed between hosts < ONLY HDFS as service of my cluster > !

[#1]

Hello Community,

I cant solve the problem of connections between hosts caused by Errno:111 !!

My :

1. hostname is right,
2. iptables is stoped,
3. selinux is stoped.

Here is the log of starting the name node of my cluster.

Mysafemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused 2019-06-07 10:07:14,531 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://node4.rh.bigdata.cluster:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused 2019-06-07 10:07:32,086 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://node4.rh.bigdata.cluster:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused 2019-06-07 10:07:48,653 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://node4.rh.bigdata.cluster:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused 2019-06-07 10:08:06,283 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://node4.rh.bigdata.cluster:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefused 2019-06-07 10:08:22,948 - Retrying after 10 seconds. Reason: Execution of '/usr/hdp/current/hadoop-hdfs-namenode/bin/hdfs dfsadmin -fs hdfs://node4.rh.bigdata.cluster:8020 -safemode get | grep 'Safe mode is OFF'' returned 1. safemode: Call From node4.rh.bigdata.cluster/172.16.138.113 to node4.rh.bigdata.cluster:8020 failed on connection exception: java.net.ConnectException: Connection refused; For more details see:  http://wiki.apache.org/hadoop/ConnectionRefuse

[#2]

@Adil BAKKOURI

The below output means your name node is in safe mode which means it won't allow any changes to the cluster as it won't be able to record that change. The return code 1 is like an exit code 1

A Safemode for Namenode is essentially a read-only mode for the HDFS cluster, where it does not allow any modifications to file system or blocks. Normally, Namenode disables safe mode automatically at the beginning

Cause: Your name node has not

• FSimage is a point-in-time snapshot of HDFS's namespace.
• Edit log records every change from the last snapshot. The last snapshot is actually stored in FSImage.

-safemode get | grep 'Safe mode is OFF'' returned 1.

# su - hdfs

Get the current name node status of the output should validate the return code 1

$ hdfs dfsadmin -safemode get

If the output is safe mode on then proceed to save Namespace

$ hdfs dfsadmin -safemode enter

Force the savepoint for the namespace

$ hdfs dfsadmin -saveNamespace

Quit the safe mode

$ hdfs dfsadmin -safemode leave

Begin normal operation check if you need to restart and services do that but now you should be able to connect to the namenode

HTH