Kubernetes install with kubeadm

Disable SELinux.

setenforce 0
sed -i --follow-symlinks 's/SELINUX=enforcing/SELINUX=disabled/g'
/etc/sysconfig/selinux

Enable the br_netfilter module for cluster communication.

modprobe br_netfilter
echo '1' > /proc/sys/net/bridge/bridge-nf-call-iptables

Disable swap to prevent memory allocation issues.

 Swapoff -a
 Vim /etc/fstab.  ->  Comment out the swap line

Install Docker CE.

Install the Docker prerequisites.

 yum install -y yum-utils device-mapper-persistent-data lvm2

Add the Docker repo and install Docker.

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

Add the Kubernetes repo.

 cat <<EOF > /etc/yum.repos.d/kubernetes.repo
 [kubernetes]
 name=Kubernetes
 baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
 enabled=1
 gpgcheck=0
 repo_gpgcheck=0
 gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
         https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
 EOF

Install Kubernetes.

 yum install -y kubelet kubeadm kubectl

Reboot.

Enable and start Docker and Kubernetes.

systemctl enable docker
systemctl enable kubelet
systemctl start docker
systemctl start kubelet

Check the group Docker is running in.

docker info | grep -i cgroup

Set Kubernetes to run in the same group.

sed -i 's/cgroup-driver=systemd/cgroup-driver=cgroupfs/g' /etc/systemd/system/kubelet.service.d/10-kubeadm.conf

Reload systemd for the changes to take effect, and then restart Kubernetes.

systemctl daemon-reload
systemctl restart kubelet

*Note: Complete the following section on the MASTER ONLY!

Initialize the cluster using the IP range for Flannel.

kubeadm init --pod-network-cidr=10.244.0.0/16

Copy the kubeadmin join command.

Deploy Flannel.

kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml

Check the cluster state.

Kubectl get pods —all-namespaces

Note: Complete the following steps on the NODES ONLY!

Run the join command that you copied earlier, then check your nodes from the master.

kubectl get nodes