INSTALL KUBERNETES CENTOS 7

How to install Kubernetes

Configure Host | Master And Node

Using your editor edit hosts

sudo vi /etc/hosts

Add your node and master example

192.168.1.1 kubemaster
192.168.1.2 kubenode
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain

Disable Selinux | Master And Node

In this tutorial, we will not cover about SELinux configuration for Docker, so we will disable it.

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

Enable br_net_filter Kernel Module | Master And Node

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

Disable Swap | Master And Node

swapoff -a

then comment your fstab example

#/dev/mapper/centos_localhost--live-swap swap                    swap    defaults        0 0

Install Docker | Master And Node

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

Add the docker repository to the system and install docker-ce using the yum command.

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

Install Kubernetes | Master And Node

Add the kubernetes repository to the centos 7 system by running the following command.

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=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg
        https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg
EOF

then

yum install -y kubelet kubeadm kubectl

reboot your master and node

reboot

Log in again to the server and start the services, docker and kubelet.

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

Change the cgroup-driver | Master And Node

docker info | grep -i cgroup

And you see the docker is using 'cgroupfs' as a cgroup-driver.

Now run the command below to change the kuberetes cgroup-driver to 'cgroupfs'.

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

Now we're ready to configure the Kubernetes Cluster.

Kubernetes Cluster Initialization | Master

kubeadm init --apiserver-advertise-address=<master_ip> --pod-network-cidr=<your_cidr>

Note:

Copy the 'kubeadm join ... ... ...' command to your text editor. The command will be used to register new nodes to the kubernetes cluster.

Now in order to use Kubernetes, we need to run some commands as on the result.

Create new '.kube' configuration directory and copy the configuration 'admin.conf'.

mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config

Next, deploy the flannel network to the kubernetes cluster using the kubectl command.

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

Wait for a minute and then check kubernetes node and pods using commands below.

kubectl get nodes
kubectl get pods --all-namespaces

Adding Node to the Cluster | Node

You Rember in kubeadm join..... copy from your editor then exec from your nodes example :

kubeadm join 192.168.1.1:6443 --token vzau5v.vjiqyxq26lzsf28e --discovery-token-ca-cert-hash sha256:e6d046ba34ee03e7d55e1f5ac6d2de09fd6d7e6959d16782ef0778794b94c61e

Wait for some minutes and back to the 'master' master cluster server check the nodes and pods using the following command.

Check your node from master

kubectl get nodes
kubectl get pods --all-namespaces

Installing Dashboard

See Next Time

How To Use BASH Excecution

You can execute the run.sh file

sudo ./run.sh

Select the List of Functions that exist then execute each step from 1-11

Testing Create First Pod | Master

In this step, we will do a test by deploying the Nginx pod to the kubernetes cluster. A pod is a group of one or more containers with shared storage and network that runs under Kubernetes. A Pod contains one or more containers, such as Docker container.

Login to the 'master' server and create new deployment named 'nginx' using the kubectl command.

kubectl create deployment nginx --image=nginx

To see details of the 'nginx' deployment sepcification, run the following command.

kubectl describe deployment nginx

And you will get the nginx pod deployment specification.

Next, we will expose the nginx pod accessible via the internet. And we need to create new service NodePort for this.

Run the kubectl command below.

kubectl create service nodeport nginx --tcp=80:80

Make sure there is no error. Now check the nginx service nodeport and IP using the kubectl command below.

kubectl get pods
kubectl get svc

from your master curl on port (remember port from your service | kubectl get svc)

curl node:30691

then from your browser open url : node_ip:30691