How to install kubernetes – Docker

Let's consider 1 Kubernetes-Cluster and 2 Worker-Nodes

1. While launching AWS ec2 instances, make sure that you open all the ports in the related security groups.
2. All EC2 instances need to be on the same VPC and in the same availability zone.
3. For K8-Cluster minimum requirement is t2.large
4. For Worker-Nodes minimum requirement is t2.micro
5. Login to putty/terminal to connect to your EC2 instances.

Run the following Commands on both K8-Cluster and Worker-nodes

• Be a root user. Install Docker and start Docker service. Also, enable the docker service so that the docker service starts on the system restarts.

sudo su
yum install docker -y 
systemctl enable docker && systemctl start docker

• Create proper yum repo files so that we can use yum commands to install the components of Kubernetes.

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=1

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

exclude=kube*

EOF

• sysctl command is used to modify kernel parameters at runtime. Kubernetes needs to have access to the kernel’s IP6 table and so we need to do some more modifications. This includes disabling secure Linux.

cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF

sysctl --system
setenforce 0

• Install kubelet, kubeadm and kubectl; start kubelet daemon

yum install -y kubelet kubeadm kubectl --disableexcludes=kubernetes
systemctl enable kubelet && systemctl start kubelet

vi /etc/docker/daemon.json

{
    "exec-opts": ["native.cgroupdriver=systemd"]
}

• restart docker and kubelet; reload daemon

 sudo systemctl daemon-reload
 sudo systemctl restart docker
 sudo systemctl restart kubelet

Only on the Master Node:

• On the master node initialize the cluster.

kubeadm init --ignore-preflight-errors all

• To make kubeconfig file permanent , paste the export KUBECONFIG=/etc/kubernetes/admin.conf after export PATH in .bash_profile

ls -al
vi .bash_profile

export KUBECONFIG=/etc/kubernetes/admin.conf

On All Worker nodes :

• Copy kubeadm join command from the output of kubeadm init on the master node.

<kubeadm join command copied from master node>

# kubeadm join 172.31.37.128:6443 --token sttk5b.vco0jw5bkkf1toa4 
                 --discovery-token-ca-cert-hash sha256:d77b5f865c1e30b73ea4dd7ea458f79f56da94f9de9c8d7a26b226d94fd0c49e

On the Master Node :

• Create weave-net.

kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d 'n')"

kubectl get nodes

That's it :)