I have a 3 node HA cluster in a CentOS 8 VM. I am using ZK 3.7.0 and Hadoop 3.3.1. In my cluster I have 2 namenodes, node1 is the active namenode and node2 is the standby namenode in case that node1 falls. The other node is the datanode I just start all with the command

start-dfs.sh

In node1 I had the following processes running: NameNode, Jps, QuorumPeerMain and JournalNode In node2 I had the following processes running: NameNode, Jps, QuorumPeerMain, JournalNode and DataNode.
My hdfs-site.xml configuration is the following:

<property>
        <name>dfs.replication</name>
        <value>2</value>
    </property>
    <property>
        <name>dfs.namenode.name.dir</name>
        <value>/datos/namenode</value>
    </property>
    <property>
        <name>dfs.datanode.data.dir</name>
        <value>/datos/datanode</value>
    </property>
    <property>
        <name>dfs.nameservices</name>
        <value>ha-cluster</value>   
    </property>
    <property>
        <name>dfs.ha.namenodes.ha-cluster</name>
        <value>nodo1,nodo2</value>
    </property>
    <property>
        <name>dfs.permissions</name>
        <value>false</value>
    </property>
    <property>
        <name>dfs.namenode.rpc-address.ha-cluster.nodo1</name>
        <value>nodo1:8020</value>
    </property>
    <property>
        <name>dfs.namenode.rpc-address.ha-cluster.nodo2</name>
        <value>nodo2:8020</value>
    </property>
    <property>
        <name>dfs.namenode.http-address.ha-cluster.nodo1</name>
        <value>nodo1:9870</value>
    </property> 
    <property>
        <name>dfs.namenode.http-address.ha-cluster.nodo2</name>
        <value>nodo2:9870</value>
    </property>
    <property>
        <name>dfs.namenode.shared.edits.dir</name>
        <value>qjournal://nodo3:8485;nodo2:8485;nodo1:8485/ha-cluster</value>
    </property>

The problem is that since the node2 is the standby namenode I didn't want it to have the DataNode process running, so I killed it. I used the command kill -9 (I know it's not the best way, I should have used hdfs --daemon stop datanode). Then I entered the hadoop website to check how many datanodes I had. In the node1 (the active namenode) Hadoop website, in the datanode part I only had 1 datanode, node3. The problem is that in the Hadoop website of the node2 (the standby namenode) was like this:

In case u can't see the image:

default-rack/nodo2:9866 (192.168.0.102:9866)    http://nodo2:9864   558s        

/default-rack/nodo3:9866 (192.168.0.103:9866)   http://nodo3:9864   1s

The node2 datanode hasn't been alive for 558s and it doesn't take the node as dead. Does anybody know why does this happen??