Kubernetes-Setup

Install Kubernetes on Ubuntu 18.04 LTS


*********************
Step1: On All Machines ( Master & All nodes ):
**********************
### INSTALL DOCKER 

sudo apt-get update
sudo apt-get install -y apt-transport-https ca-certificates curl software-properties-common

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
sudo apt-get update ; clear
sudo apt-get install -y docker-ce
sudo service docker start ; clear

### INSTALL KUBEADM,KUBELET,KUBECTL

echo "deb http://apt.kubernetes.io/ kubernetes-xenial main" | sudo tee /etc/apt/sources.list.d/kubernetes.list
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add -
sudo apt-get update ; clear
sudo apt-get install -y kubelet kubeadm kubectl	


************************
Step2: On Master only:
***********************

sudo kubeadm init --ignore-preflight-errors=all

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

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

kubectl get nodes
kubectl get all --all-namespaces


**********Step: if Kubelet is not healthy error***************

sudo mkdir /etc/docker
cat <<EOF | sudo tee /etc/docker/daemon.json
{
"exec-opts": ["native.cgroupdriver=systemd"],
"log-driver": "json-file",
"log-opts": {
"max-size": "100m"
},
"storage-driver": "overlay2"
}
EOF

sudo systemctl enable docker
sudo systemctl daemon-reload
sudo systemctl restart docker

Check if the kubelet became running:
sudo systemctl status kubelet

The procedure is in:

https://kubernetes.io/docs/setup/production-environment/container-runtimes/#docker
**************************************

**********************
Step3: On Nodes only:
**********************
copy the kubeadm join token from master & run it on all nodes
      
Ex: kubeadm join 10.128.15.231:6443 --token mks3y2.v03tyyru0gy12mbt \
       --discovery-token-ca-cert-hash sha256:3de23d42c7002be0893339fbe558ee75e14399e11f22e3f0b34351077b7c4b56


how to find kubeadm join token later
****************************
kubeadm token create --print-join-command --ttl=0


## Install Kubernetes on CENTOS 

### Step1: `On All Machines ( Master & All nodes ):`

     ### Set SELinux in permissive mode (effectively disabling it)
     
     setenforce 0
     sed -i 's/^SELINUX=enforcing$/SELINUX=permissive/' /etc/selinux/config

     ### Install Docker
     
     sudo yum remove -y docker docker-client docker-client-latest docker-common docker-latest docker-latest-logrotate docker-logrotate docker-engine docker-ce docker-ce-cli containerd.io
     sudo yum install -y yum-utils device-mapper-persistent-data lvm2
     sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
     sudo yum install -y docker-ce docker-ce-cli containerd.io
     systemctl enable --now docker
     systemctl start docker

     ### Install kubeadm,kubelet,kubectl
     
     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

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

### Step2: `On Master only:`

    sudo kubeadm init --ignore-preflight-errors=all

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

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

    kubectl get nodes
    kubectl get all --all-namespaces

### Step3: `On Nodes only:`

    copy the kubeadm join token from master & run it on all nodes

    Ex: kubeadm join 10.128.15.231:6443 --token mks3y2.v03tyyru0gy12mbt \
           --discovery-token-ca-cert-hash sha256:3de23d42c7002be0893339fbe558ee75e14399e11f22e3f0b34351077b7c4b56