--> create 2 ec2 instances, one for master node(nady-kube-master) and another for worker node(nady-kube-worker)...N.b.: While doing that remember to choose t2 medium otherwise you cant initialize kubeadm.
-->now for both machines
sudo apt update
sudo apt install docker.io -y
->enabling docker on both instances:
sudo systemctl start docker
sudo systemctl enable docker
->downloading https and curl dependencies
sudo apt install apt-transport-https curl
->adding ubuntu repository to download kubernetes services
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"
->installing kubernetes modules:
sudo apt install kubeadm kubelet kubectl kubernetes-cni
->disabling swap memory:
sudo swapoff -a
-->To change the hostnames of both machines:-
->On master machine:
sudo hostnamectl set-hostname kube-master
->on worker machine:
sudo hostnamectl set-hostname kube-worker1
sudo kubeadm init
warning: kubelet is not running or healthy
go to sudo vi /etc/docker/daemon.json
input the following:
{ "exec-opts": ["native.cgroupdriver=systemd"] }
restarting docker and kubelet:
sudo systemctl daemon-reload
sudo systemctl restart docker
sudo systemctl restart kubelet
resetting kubeadm
sudo kubeadm reset
sudo kubeadm init
Kubeconfig to access Kubectl command
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
same. (except the kubeconfig to access kubectl command part)
then from worker node:
sudo kubeadm join 10.1.1.36:6443 --token 1zyxyl.m4wjgzqe8i3mrmfk --discovery-token-ca-cert-hash sha256:9186e7c4ef1d8bfaa3a605d245499580abfc1fa2cd32974ff33dbd7f5e744b2c(6443 is the api server port)
(based on this token info from master machine)
Never forget to put sudo before kubeadm...will give you a hard time if you forget...
kubectl get pods
kubectl get pods -A
to use a network fabric/POD network:
kubectl apply -f "https://cloud.weave.works/k8s/net?k8s-version=$(kubectl version | base64 | tr -d '\n')"
because if we hit kubectl get nodes we can see that the nodes aren't ready yet, but pretty soon after creating the pod network the nodes will be ready.
vi deployment.yaml
paste the folowing :
apiVersion: apps/v1 # for k8s versions before 1.9.0 use apps/v1beta2 and before 1.8.0 use extensions/v1beta1 kind: Deployment metadata: name: frontend spec: selector: matchLabels: app: guestbook tier: frontend replicas: 3 template: metadata: labels: app: guestbook tier: frontend spec: containers: - name: php-redis image: nginx resources: requests: cpu: 100m memory: 100Mi env: - name: GET_HOSTS_FROM value: dns # If your cluster config does not include a dns service, then to # instead access environment variables to find service host # info, comment out the 'value: dns' line above, and uncomment the # line below: # value: env ports: - containerPort: 80
N.b.: press qa twice to insert, esc to end/cancel editing, :wq to save and exit
kubectl apply -f deployment.yaml
to check and confirm the deploymment of pods :
kubectl get pods
we can delete pods by kubectl delete pods *name of a pod*
but if you kubectl get pods there will be another pod just respawned because of the command replicas: 3 in the deployment file.
vi service.yaml
paste the folowing :
apiVersion: v1 kind: Service metadata: name: frontend labels: app: guestbook tier: frontend spec: type: NodePort ports: -port: 80 selector: app: guestbook tier: frontend
kubectl apply -f service.yaml
now we can check the services and endpoints :
kubectl get svc
kubectl get ep
now lets go to the public ip of worker node from browser with the port of frontend on the master node which is 32481
from browser http://13.232.69.8:32481/...you can see the nginx page !!!!
To simply put it ; deployment(an octopus) keeps the pods alive and and the traffic/request is reached to the pods through service.