Performing prerequisite tasks

Before we begin installing and setting up our Kubernetes, here are a few prerequisites tasks:

1. Install socat. For Helm, socat is used to set the port forwarding for both the Helm client and Tiller:

# yum -y install socat

2. Set SELINUX=disabled in /etc/selinux/config and then reboot for it to take effect. After the reboot, you should get an output from getenforce as permissive:

# getenforce
Disabled

3. Add the Docker repository:

# yum -y install yum-utils
# yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

4. Install Docker. Since we will be working with Kubernetes 1.15.6, the tested version of Docker for this release is 3:18.09.8-3.el7.

We will switch the Docker cgroup driver from cggroupfs to systemd:

# mkdir -p /etc/docker
# cat > /etc/docker/daemon.json <<EOF
{
  "exec-opts": ["native.cgroupdriver...