A company is planning on using the EMR service for their Big data processing needs. The database administrator needs to have the ability to login into the nodes. Which of the following needs to be place for this requirement to be fulfilled.

Answer options:

A.An IAM Role which allows access to the underlying servers
B.An IAM User which has access to the underlying servers
C.SSH connections allowed via the Security Groups
D.SSH connections allowed via IAM Policies

Answer – C
The AWS Documentation mentions the following
Security groups act as virtual firewalls to control inbound and outbound traffic to your cluster. The default Amazon EMR-managed security groups associated with cluster instances do not allow inbound SSH connections as a security precaution. To connect to cluster nodes using SSH so that you can use the command line and view web interfaces that are hosted on the cluster, you need to add inbound rules that allow SSH traffic from trusted clients. 
Options A and B are incorrect since the roles and users don’t have an impact on the SSH inbound connections
Option D is incorrect since IAM Policies would not determine the underlying SSH connections
For more information on using SSH for cluster nodes, please refer to the below URL
https://docs.aws.amazon.com/emr/latest/ManagementGuide/emr-gs-ssh.html