Kubernetes

Setting up Kubernetes Clusters using Kubeadm Manual way in Ubuntu 16.04 Xenial

August 29, 2019 comments off
How to delete/remove/clean existing corrupted or old kubeadm kubernetes clusters setup?

What is Kubeadm?

Kubeadm helps you bootstrap a minimum viable Kubernetes cluster that conforms to best practices. Kubeadm is a tool built to provide kubeadm init and kubeadm join as best-practice “fast paths” for creating Kubernetes clusters.

Goal

  • To Install a single master Kubernetes cluster
  • To Install a high availability master Kubernetes cluster
  • To Install a Pod network on the cluster so that your Pods can talk to each other.

kubeadm’s simplicity means it can serve a wide range of use cases:

  • New users can start with kubeadm to try Kubernetes out for the first time.
  • Users familiar with Kubernetes can spin up clusters with kubeadm and test their applications.
  • Larger projects can include kubeadm as a building block in a more complex system that can also include other installer tools.

Pre-requisite

  • One or more machines running a deb/rpm-compatible OS, for example Ubuntu or CentOS
  • 2 GB or more of RAM per machine. Any less leaves little room for your apps.
  • 2 CPUs or more on the master
  • Full network connectivity among all machines in the cluster. A public or private network is fine

As part of the installation, every node (master and minions) needs:

  • Docker
  • Kubelet
  • Kubeadm
  • Kubectl
  • CNI

Step 1 – Update Ubuntu and install apt-transport-https


$ apt-get update && apt-get install -y apt-transport-https
$ curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add -

Step 2 – Add Ubuntu apt repo for docker kubeadm kubectl kubelet kubernetes-cni


$ cat <<EOF >/etc/apt/sources.list.d/kubernetes.list
deb http://apt.kubernetes.io/ kubernetes-xenial main
EOF

Step 3 – Install docker kubeadm kubectl kubelet kubernetes-cni


$ apt-get update
$ apt-get install -y docker.io kubeadm kubectl kubelet kubernetes-cni
$ apt-get install -y docker.io kubeadm kubectl kubelet kubernetes-cni

Step 4 – Finally, initialize a kubernetes clusters


$ kubeadm init

Step 5 – Output

To start using your cluster, you need to run the following as a regular user:

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

You should now deploy a pod network to the cluster.
Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at:
  https://kubernetes.io/docs/concepts/cluster-administration/addons/

Then you can join any number of worker nodes by running the following on each as root:

kubeadm join 172.31.25.244:6443 --token 1j1lj9.bw6nb02omjv92owd \
    --discovery-token-ca-cert-hash sha256:caca50bf253855d96133c6fdde763629a6fba07d8c57b6b52eacece83f88b4b9

Step 6 – Setup Workstation in the Master node only. You can be regular user for it.


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

Step 7 – Verify Clustors


$ kubectl get nodes
$ kubectl get pods --all-namespaces

Step 8 – Install Kubernetes pod networking

Weave Net provides networking and network policy, will carry on working on both sides of a network partition, and does not require an external database. Kubernetes versions 1.6 and above:

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

Step 9 – Setup nodes [ In the node aka worker ]

# Follow Step 1 
# Follow Step 2
# Follow Step 3
# Run following commands which we got from kubeadm init
$ kubeadm join 172.31.31.106:6443 --token pdn6in.r0dzhpx1ucrs69au --discovery-token-ca-cert-hash sha256:a9385951e659a3c67f55ccfbdc1169b1f660ba09aaf8cc6d5cc96d71b71900d2
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