Apache Hadoop multi-node cluster failed not showing remote Datanode - hadoop

Question

I'm having a hard time with setting up a multi-node cluster. I have a Razer running Ubuntu 20.04 and a IMAC running OSX Catalina. Razer is the host namenode and both the Razer and IMAC are set are the datanodes (slave workers). Both computers have SSH-keys replicated so they can SSH connect without any password. However, I'm having problems with showing the remote datanode from the IMAC as Live on my Hadoop dashboard. I can see the datanode live from the Razer I think it has something to do with my remote machine MAC not being able to connect to the HDFS which I set in the core-site.xml as hfds://hadoopmaster:9000.
RAZER = Hostname: Hadoopmaster
IMAC = Hostname: Hadoopslave
Based on some troubleshooting, I reviewed the datanode logs in the IMAC and saw that it is refusing to connect to hadoopmaster on port 9000.
2020-06-01 13:44:33,193 INFO org.apache.hadoop.ipc.Client: Retrying connect to server:
hadoopmaster/192.168.1.191:8070. Already tried 6 time(s); retry policy is
RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2020-06-01 13:44:35,550 INFO org.apache.hadoop.ipc.Client: Retrying connect to server:
hadoopmaster/192.168.1.191:8070. Already tried 7 time(s); retry policy is
RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2020-06-01 13:44:36,574 INFO org.apache.hadoop.ipc.Client: Retrying connect to server:
hadoopmaster/192.168.1.191:8070. Already tried 8 time(s); retry policy is
RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2020-06-01 13:44:37,597 INFO org.apache.hadoop.ipc.Client: Retrying connect to server:
hadoopmaster/192.168.1.191:8070. Already tried 9 time(s); retry policy is
RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2020-06-01 13:44:37,619 WARN org.apache.hadoop.hdfs.server.datanode.DataNode: Problem
connecting to server: hadoopmaster/192.168.1.191:8070
2020-06-01 13:44:44,660 INFO org.apache.hadoop.ipc.Client: Retrying connect to server:
hadoopmaster/192.168.1.191:8070. Already tried 0 time(s); retry policy is
RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2020-06-01 13:44:45,534 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: RECEIVED
SIGNAL 15: SIGTERM
2020-06-01 13:44:45,537 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: SHUTDOWN_MSG:
Here are my settings:
hdfs-site.xml
<configuration>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
</configuration>
core-site.xml
<configuration>
<property>
<name>hadoop.tmp.dir</name>
<value>/usr/local/Cellar/hadoop/hdfs/tmp</value>
<description>A base for other temporary directories</description>
</property>
<property>
<name>fs.default.name</name>
<value>hdfs://hadoopmaster:8070</value>
</property>
</configuration>
So I think there's issues with connecting to port 9000 on my machine. So my next step was testing out the ssh connections in my terminal command window:
IMAC Command: ssh username#hadoopmaster -p 9000
Results:
Refused to connect
So my next step was performing the SSH command on my Razer machine:
Razer Command: ssh hadoopmaster -p 9000
Results:
Refused to connect
So I tried on my Razer to modify the UFW firewall to open port 9000, any to hadoopmaster, all ports, and still no luck.
Please help me have my remote machine IMAC connect to port 9000 on the Razer so I can create the hadoop cluster in my network and view the remote slave machines as live datanodes on the dashboard.