I have been repeatedly trying to start datanode but it fails with bind exception saying address is already in use even though port is free

I used below commands to check

netstat -a -t --numeric-ports -p | grep 500

I have overridden default port 50070 with 50081 but the issue still persists.

Starting DataNode with maxLockedMemory = 0
Opened streaming server at /172.19.7.160:50081
Balancing bandwith is 10485760 bytes/s
Number threads for balancing is 5
Waiting for threadgroup to exit, active threads is 0
Shutdown complete.
Exception in secureMain
java.net.BindException: bind(2) error: Address already in use when trying to bind to '/var/run/hdfs-sockets/datanode'
    at org.apache.hadoop.net.unix.DomainSocket.bind0(Native Method)
    at org.apache.hadoop.net.unix.DomainSocket.bindAndListen(DomainSocket.java:191)
    at org.apache.hadoop.hdfs.net.DomainPeerServer.<init>(DomainPeerServer.java:40)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.getDomainPeerServer(DataNode.java:907)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.initDataXceiver(DataNode.java:873)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.startDataNode(DataNode.java:1066)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.<init>(DataNode.java:411)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:2297)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:2184)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:2231)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:2407)
    at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:2431)
Exiting with status 1