INSTALL KUBERNETES

Kubernetes Installation

# Install Docker

sudo apt install docker.io

# Fix Docker access

sudo groupadd docker

sudo usermod -aG docker $USER

if did not work

sudo chmod 777 /var/run/docker.sock

# Enable Docker

sudo systemctl enable docker

# Add Kubernetes Repo

curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add

sudo apt-add-repository "deb http://apt.kubernetes.io/ kubernetes-xenial main"

# Install Kube Admin

sudo apt install kubeadm

sudo apt install -y kubelet kubeadm kubectl kubernetes-cni

sudo kubeadm version

systemctl status kubectl

# Switch-off all swap permantly

sudo vi /etc/fstab

- comment out all swaps by adding the hash(#) sign.

# Set Master Hostname

sudo hostnamectl set-hostname master-node

sudo vi /etc/hostname

and manualy edit the host name to master-node

hostnamectl set-hostname slave-node (For slave only)

# Install Docker CE (Optional?)

sudo su

## [WARNING IsDockerSystemdCheck]: detected "cgroupfs" as the Docker cgroup driver. The recommended driver is "systemd". Please follow the guide at https://kubernetes.io/docs/setup/cri/

error execution phase preflight: [preflight] Some fatal errors occurred:

## Set up the repository:

### Install packages to allow apt to use a repository over HTTPS

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

### Add Docker’s official GPG key

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -

### Add Docker apt repository.

add-apt-repository \

"deb [arch=amd64] https://download.docker.com/linux/ubuntu \

$(lsb_release -cs) \

stable"

## Install Docker CE.

apt-get update && apt-get install docker-ce=18.06.2~ce~3-0~ubuntu

# Setup daemon.

cat > /etc/docker/daemon.json <<EOF

{

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

"log-driver": "json-file",

"log-opts": {

"max-size": "100m"

},

"storage-driver": "overlay2"

}

EOF

mkdir -p /etc/systemd/system/docker.service.d

# Restart docker.

systemctl daemon-reload

systemctl restart docker

# Initialize Kubernetes in Master node

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

OR (Ignore pre-flight errors)

sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=SystemVerification,FileContent--proc-sys-net-bridge-bridge-nf-call-iptables

sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --ignore-preflight-errors=SystemVerification,FileContent--proc-sys-net-bridge-bridge-nf-call-iptables,FileAvailable--etc-kubernetes-manifests-kube-apiserver.yaml,FileAvailable--etc-kubernetes-manifests-kube-controller-manager.yaml,FileAvailable--etc-kubernetes-manifests-kube-scheduler.yaml,FileAvailable--etc-kubernetes-manifests-etcd.yaml

# Resetting nodes

sudo kubeadm reset

sudo rm -rf /etc/kubernetes/

# Manage kube for devkinetics account

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

# Map Nodes to Master. Only for worker nodes

Note: EXAMPLE ONLY! Refer to installation logs for the ACTUAL command.

kubeadm join 192.168.0.131:6443 --token nm1eht.q4yi53mco4n75m7j \

--discovery-token-ca

-cert-hash sha256:3a614688fff904414b5bc19f6cdfc0aab979ff23bb37e7935d0f917a130ab7e0

# To check if there are swaps running.Must retrun none.

- It takes several minutes to switch-off swap

sudo swapon -s

# Install Flannel

- Flannel is a simple and easy way to configure a layer 3 network fabric designed for Kubernetes.

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

# Install weavework (Better)

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

Reference

https://vitux.com/install-and-deploy-kubernetes-on-ubuntu/

Trouble Shooting

The connection to the server 192.168.0.131:6443 was refused - did you specify the right host or port?

Try... Check if you have internet connection

Try... Waiting, it takes at least a min

Try... switchooff all swap

1. sudo -i

2. swapoff -a

3. exit

4. strace -eopenat kubectl version

Try... check if there are running swaps

systemctl status kubelet

1. sudo swapon -s

2. sudo swapoff /dev/XXXX

Try... Reconfiguring config files

rm -fr $HOME/.kube

mkdir -p $HOME/.kube

sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

sudo chown $(id -u):$(id -g) $HOME/.kube/config

Try... Adding --server parameter

kubectl --server=192.168.0.131:6443 get pod

Try... checking the context setup

# View current configuration

$ kubectl config view

# View current Contexts

kubectl config get-contexts

# Set the cluster URL

kubectl config set-cluster cluster --server=http://192.168.0.131:6443

kubectl config set-cluster cluster --server=http://23.92.53.254:6443

# Map the updateded URL

kubectl config set-context kubernetes-admin@kubernetes --cluster=cluster

# Use the updateded context

kubectl config use-context kubernetes-admin@kubernetes

# Test

kubectl get nodes

Try... checking if the port is open

# Test port

sudo netstat -pnlt

sudo netstat -pnlt | grep 6443

Should return like this --> tcp6 0 0 :::6443 :::* LISTEN 4546/kube-apiserver

# Open the port

sudo apt-get install ufw

sudo ufw allow from any to any port 6443 proto tcp

sudo ufw allow 10248

systemctl status kubelet.service (No Error)

systemctl status kubelet (Error)

Check Logs

sudo journalctl -xeu kubelet

sudo systemctl status kubelet

Purge

sudo kubeadm reset

sudo apt-get purge kubeadm kubectl kubelet kubernetes-cni kube*

sudo rm -rf /etc/kubernetes/

sudo apt-get autoremove

sudo rm -rf ~/.kube