edited script for installing docker on RHEL based OS. Modified from kubernetes.io install snip.

docker_install.sh

# Install Docker CE
## Set up the repository
### Install required packages.
yum install -y yum-utils device-mapper-persistent-data lvm2

### Add Docker repository.
yum-config-manager \
  --add-repo \
  https://download.docker.com/linux/centos/docker-ce.repo

## Install Docker CE.
yum install -y docker-ce-18.06.2.ce

## Create /etc/docker directory.
if [ ! -x /etc/docker ]; then
    mkdir /etc/docker
fi

# Setup daemon.
cat > /etc/docker/daemon.json <<EOF
{
  "exec-opts": ["native.cgroupdriver=systemd"],
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "100m"
  },
  "storage-driver": "overlay2",
  "storage-opts": [
    "overlay2.override_kernel_check=true"
  ]
}
EOF

mkdir -p /etc/systemd/system/docker.service.d

# Restart Docker
systemctl daemon-reload
systemctl enable --now docker

used this to run minikube on a VM running centos7u6.