Kubernetes with Ansible

About

This project can be used to setup a Kubernetes cluster with HA control panes and HA Etcd cluster using Ansible. It provides three playbooks:

Playbook	Description
playbook-k8s-all.yml	Complete Kubernetes cluster installation.
playbook-kubeadm-add-new-master.yml	Add new master(s) to an existing cluster.
playbook-kubeadm-add-new-worker.yml	Add new worker(s) to an existing cluster.

Requirements

• Ansible 2.8
• Virtual Machines with CentOS8 ready when not using Vagrant

Ansible

Before running the playbooks you need to copy your SSH key to the remote servers.

# copy ssh keys
$ for i in {21,22,23,24}
  do
      sshpass -p "vagrant" ssh-copy-id vagrant@172.16.88.$i
      sshpass -p "vagrant" ssh-copy-id root@172.16.88.$i
      echo "172.16.88.$i done"
  done

You will need to prepare an inventory file for Ansible. There are examples you can copy and edit in the inventories/examples folder. Place them in the inventories folder and you are good to go.

After that export the Ansible configuration and you are ready to run the playbooks.

$ export ANSIBLE_CONFIG=./ansible.cfg

It is advised to run a syntax check to be sure all needed variabled are filled in and there are no syntax errors.

# Run a syntax check
$ ansible-playbook playbook-k8s-all.yml \
  -i inventories/vagrant-full-install.inv \
  -u vagrant \
  --ask-become-pass \
  --syntax-check

Install the playbooks:

• Complete Kubernetes cluster installation:

  # Complete installation
  $ ansible-playbook \
      -i inventories/vagrant-full-install.inv \
      -u vagrant \
      --ask-become-pass \
      playbook-k8s-all.yml

• Add new master(s) to an existing cluster:

  # Add masters
  $ ansible-playbook \
      -i inventories/vagrant-add-master.inv \
      -u vagrant \
      --ask-become-pass \
      playbook-kubeadm-add-new-master.yml

• Add new worker(s) to an existing cluster:

  # Add workers
  $ ansible-playbook \
      -i inventories/vagrant-add-worker.inv \
      -u vagrant \
      --ask-become-pass \
      playbook-kubeadm-add-new-worker.yml

Known Issues

• When running the Ansible playbook using WSL you might get the following warning:

  [WARNING] Ansible is being run in a world writable directory, ignoring it as an ansible.cfg source. For more information see https://docs.ansible.com/ansible/devel/reference_appendices/config.html#cfg-in-world-writable-dir This can be solved by the following command:

  export ANSIBLE_CONFIG=./ansible.cfg

TODO

• Check to NOT join master/worker if already "Ready"
• Taint master to allow running pods on the master node in "init-first-master" role
• Support for Calico CNI
• Add the option to add new nodes to the etcd cluster when adding masters

Contributors

• Jorik Seldeslachts