Removing DataNodes manually

The CES HDFS NameNodes and DataNodes do not need to be stopped when adding or deleting DataNodes from the cluster.

To remove a DataNode from the CES HDFS cluster, perform the following steps:

On the DataNode as root, stop the DataNode service.
```
# mmhdfs datanode stop
```
On the NameNode as root, edit the workers configuration file to remove the DataNode from the DataNode list.
```
# vi /var/mmfs/hadoop/etc/hadoop/workers 
```
On the NameNode as root, upload the modified configuration into CES.
```
# mmhdfs config upload
```
On the NameNode, confirm that the DataNode is not shown from the DataNode list by running the following command:
```
# mmhdfs hdfs-dn status
```

Note: The HDFS Transparency NameNodes must be restarted to fetch the information about the removed DataNode. Before this restart is completed, the removed DataNode is listed as "dead datanode" if you run the hdfs dfsadmin -report command.