Kubernetes

This is the tutorial that documents the process to install Kubernetes 1.9.3 on four Ubuntu Linux VMs.

Install Master

A new VM will be created, called sandbox, with 2 CPUs, 4GB memory and 30GB hard drive. This server is installed in the Ubuntu 16.04 LTS server. This server will act as a master only and no pods will be deployed on this VM.

The first step will install docker and you can refer to

https://medium.com/@Grigorkh/how-to-install-docker-on-ubuntu-16-04-3f509070d29c

Once docker is installed, we need to install Kubernetes repo

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

Next let’s create a kubernetes.list file

sudo vi /etc/apt/sources.list.d/kubernetes.list

Add one line as below and save it.

deb http://apt.kubernetes.io/ kubernetes-xenial main

Now let’s install Kubernetes

sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubernetes-cni

With all the packages installed, we need to initialize kubeadm, but first you need to disable swap.

sudo swapoff -a

To make permanent changes you need to comment out the swap file in /etc/fstab file

Before init kubeadms we need to find the ip address of your master server, which can be found through ifconfig

ifconfig

Once you find your network ip address you will use it to replace 10.133.15.28 in the following command line.

sudo kubeadm init --pod-network-cidr=10.244.0.0/16 --apiserver-advertise-address=10.133.15.28 --kubernetes-version stable-1.9

After the command is completed, it will show you a command to join other nodes to the master.

Something like the following.

sudo kubeadm join --token 582493.ce5e13aa64d9ccb8 10.133.15.28:6443 --discovery-token-ca-cert-hash sha256:fab46528c4a2e0d38bdf60c6ed5042a60a8535ac48443356c06d3f461204af6d

Config a user account or just use the current user if you have logged in with a non-root user.

The following is an example if you are using root so far and you want to create a new user called packet.

sudo useradd packet -G sudo -m -s /bin/bash
passwd packet

Switch to the new user with sudo su packet if you have created a new user packet. Otherwise, stay in the current user session.

$ cd $HOME
$ sudo whoami
$ sudo cp /etc/kubernetes/admin.conf $HOME/
$ sudo chown $(id -u):$(id -g) $HOME/admin.conf
$ export KUBECONFIG=$HOME/admin.conf
$ echo "export KUBECONFIG=$HOME/admin.conf" | tee -a ~/.bashrc

Apply pod network(flannel)

sudo kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.9.1/Documentation/kube-flannel.yml

sudo kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/v0.9.1/Documentation/k8s-manifests/kube-flannel-rbac.yml

Use the following command to ensure that all services are up and running on master.

kubectl get all --namespace=kube-system

Install Worker

After master is installed and all services are running, you can install workers. Here we are going to install three works: test1, test2 and test3.

Make sure that all packages are up to date.

sudo apt-get update
sudo apt-get upgrade

Make sure that docker is installed already.

sudo apt-get install -y apt-transport-https

Install key.

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

Create kubernetes.list.

echo "deb http://apt.kubernetes.io/ kubernetes-xenial main" > /etc/apt/sources.list.d/kubernetes.list

If above command doesn’t work, create the file manually with sudo vi

Once it is done, we need to install Kubernetes.

sudo apt-get update
sudo apt-get install -y kubelet kubeadm kubernetes-cni

Turn off swap by comment out the swap file system

sudo vi /etc/fstab

Turn off the current session.

sudo swapoff -a

Now join the cluster with the command given by the master.

sudo kubeadm join --token 582493.ce5e13aa64d9ccb8 10.133.15.28:6443 --discovery-token-ca-cert-hash sha256:fab46528c4a2e0d38bdf60c6ed5042a60a8535ac48443356c06d3f461204af6d

To ensure that the cluster is up and running, go to master

kubectl get nodes

And you should have something like below.

packet@sandbox:~$ kubectl get nodes
NAME                 STATUS    ROLES     AGE       VERSION
sandbox              Ready     master    1h        v1.9.3
test1                Ready     <none>    19m       v1.9.3
test2                Ready     <none>    1m        v1.9.3
test3                Ready     <none>    49m       v1.9.3

Uninstall

https://medium.com/@meysam1369/kubernetes-completely-uninstall-3f2a83dd985d

references

https://blog.alexellis.io/kubernetes-in-10-minutes/ https://medium.com/@Grigorkh/install-kubernetes-on-ubuntu-1ac2ef522a36