Creating a K8s Cluster using Ansible

0. Provisioning nodes using Vagrant

A Kubernetes cluster will consist of one master and one worker node. For this, we will be using Vagrant and VirtualBox to quickly provision virtual machines.

Create a dedicated SSH key pair to connect to the VMs:

ssh-keygen -b 4096

vagrant_key is used as a key name.

1. Creating VMs

• There will be 2 VMs. One for the master node and another for the worker node.

• Run the following command on the root folder of the project:

  cd vagrant-provision

  vagrant up

If Vms are ok then the following command should return SUCCESS like below:

cd ../kubeadm-ansible

ansible -i hosts all -m ping

worker1 | SUCCESS => { "ansible_facts": { "discovered_interpreter_python": "/usr/bin/python3" }, "changed": false, "ping": "pong" }

master | SUCCESS => { "ansible_facts": { "discovered_interpreter_python": "/usr/bin/python3" }, "changed": false, "ping": "pong" }

• The hostnames and IP addresses of the VMs are below:
  • master : 192.168.56.15
  • worker1 : 192.168.56.16

2. Master and Worker Node Setups

2.1. Common setup for the nodes (master and worker)

sudo ansible-playbook -i hosts node-init.yml

Once the playbook is finished, we need to see content below:

PLAY RECAP ***********************************************************************************

master : ok=14 changed=9 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

worker1 : ok=14 changed=9 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0

2.2. Master node setup

sudo ansible-playbook -i hosts master-node-init.yml

2.3. Worker node setup

sudo ansible-playbook -i hosts worker-node-init.yml

NOTE: Instead of the commands under 1. and 2. above, you can simply run sh install.sh on the root folder.

3. Check the Kubernetes cluster status

3.1 ssh vagrant@192.168.56.15 -i $HOME/.ssh/vagrant_key

3.2 kubectl get nodes

or set the KUBECONFIG environment variable like below:

export KUBECONFIG=<folder_of_this_project>/kubeadm-ansible/config

i.e if your project is under the ~/try/k8s/create-k8s-cluster-with-ansible/ then set the KUBECONFIG like below:

export KUBECONFIG=~/try/k8s/create-k8s-cluster-with-ansible/kubeadm-ansible/config

kubectl get nodes

4. Delete VMs

cd vagrant-provision

vagrant destroy

rm -rf .vagrant

Resources:

1. Create Kubernetes cluster with Ansible, Vagrant and kubeadm - Ivan Magdić
2. https://kubernetes.io/blog/2019/03/15/kubernetes-setup-using-ansible-and-vagrant/
3. https://stackoverflow.com/a/61769800