Your Linux VM running in VMware Cloud Director might be preconfigured with the best-practice configuration to disable root password login. This might prevent you from using the root password that you set with Director’s Guest OS Customization:
#PermitRootLogin prohibit-password
You can override this behavior using a Guest OS Customization script in a couple of ways. The simplest approach is to use your customization script to set the sshd configuration to allow root password logins:
#!/bin/bash
sed -ie "s/#PermitRootLogin prohibit-password/PermitRootLogin yes/" /etc/ssh/sshd_config
Or, if you prefer, you can use the customization script to insert an SSH public key for the root user:
#!/bin/bash
echo "ssh-rsa AAAAB3...DswrcTw==" >> /root/.ssh/authorized_keys
chmod 644 /root/.ssh/authorized_keys