Description of problem:
When I deploying the standalone master with the following variables:
   openshift_aws_create_iam_role: True
   openshift_node_use_instance_profiles: True

and get the following error message:
   "NoCredentialProviders: no valid providers in chain"

So, I check the codes: 
   roles/openshift_node/tasks/config.yml
   roles/openshift_node/tasks/bootstrap.yml

then find that:
- name: include aws provider credentials
  import_tasks: aws.yml
  when: not (openshift_node_use_instance_profiles | default(False))

It means that if we use the instance profile, then we don’t use the credentials.

But the master instances are created without instance profile.

The workaround of this problem is done by adding "instance_profile_name" option to ec2 module in,  roles/openshift_aws/tasks/provision_ec2.yml:
- name: create instance(s)
  ec2:
    instance_profile_name: "{{ l_node_group_config[openshift_aws_node_group.group].iam_role if l_node_group_config[openshift_aws_node_group.group].iam_role is defined and
 l_node_group_config[openshift_aws_node_group.group].iam_role != '' and  openshift_aws_create_iam_role  else omit }}"
   ... ...

Version-Release number of the following components:
# git describe 
openshift-ansible-3.11.0-0.35.0-104-g0d33b82

How reproducible:

Steps to Reproduce:
1. ansible-playbook -i inventory.yml -e @provision_var.yml playbooks/aws/openshift-cluster/provision_install.yml
2.
3.

Actual results:
"Sep 18 11:42:03 xxxxx atomic-openshift-node[16327]: F0917 11:42:03.673100   16327 server.go:233] failed to run Kubelet: could not init cloud provider \"aws\": error finding instance i-xxxxxx: \"error listing AWS instances: \\\"NoCredentialProviders: no valid providers in chain. Deprecated.\\\\n\\\\tFor verbose messaging see aws.Config.CredentialsChainVerboseErrors\\\"\""

Expected results:
Deploy standalone master success

Additional info:
Please attach logs from ansible-playbook with the -vvv flag