Starting namenodes on [hadoop101] hadoop101: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password). Starting datanodes

Starting namenodes on [hadoop101] means that the process of starting the namenodes on the machine named "hadoop101" is being initiated. However, in the given message, there seems to be a permission issue. The error message "Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password)" indicates that the user does not have the necessary permissions to start the namenodes.

To resolve this issue, you can try the following steps:
1. Check if you have the correct permissions to start the namenodes on the machine.
2. Ensure that you have the necessary authentication methods configured, such as public key authentication or password authentication.
3. Verify that the SSH keys are properly set up for the user attempting to start the namenodes.
4. If you are using a password for authentication, make sure you are entering the correct password.

If you are still facing issues after trying these steps, please provide more details about your setup and any specific error messages you are encountering.