Kubernetes

A role to provision a kubernetes cluster on ubuntu servers in few minutes.

Requirements

This role is to be executed on multiple ubuntu distribution based servers, Focal Fossa or Bionic Beaver or Xenial Xerus.

Role Variables

This role requires several variables within vars/main.yml and defaults/main.yml as well as extra-vars at runtime.

• NETWORK_CIDR: Take care that your Pod network must not overlap with any of the host networks, this parameter depends on your CNI plugin.
• ADDON_URI: You must deploy a Container Network Interface (CNI) based Pod network add-on so that your Pods can communicate with each other. Cluster DNS (CoreDNS) will not start up before a network is installed, defaults to flannel.
• control_plane: Flag to discover the control plane via Ip address and port.
• token: Flag used for establishing bidirectional trust between a node joining the cluster and a control-plane node.
• discovery_token_ca_cert_hash: Flag to validate the public key of the root certificate authority (CA) presented by the Kubernetes Control Plane.

Note: There are two tags depending on whether you initiate the control plane or join minions.

Example Playbook

First we run the command in comment on the playbook below on the master node (control plane) to initiate the cluster:

  ---
  - hosts: master
    roles:
      - arsalen.kubernetes
  ...
  # ansible-playbook book.yml -i hosts --skip-tags join

Once finished, we will use the generated parameters controle_plane, token and discovery_token_ca_cert_hash (displayed on stdout) to join other nodes.

Second we run the command in comment on the playbook below on the slave nodes (minions) to link each to the control plane:

  ---
  - hosts: slaves
    roles:
      - arsalen.kubernetes
  ...
  # ansible-playbook book.yml -i hosts --skip-tags initiate --extra-vars "control_plane=<control:plane> token=<to.ken> discovery_token_ca_cert_hash=<sha256:discovery-token-ca-cert-hash>"

Note: The hosts should be one master and multiple slaves, below is an example of an inventory file:

[master]
xxx.xxx.xxx.xx0 ansible_ssh_user=master-node  ansible_ssh_pass=master-node  ansible_become=yes  ansible_become_pass=master-node

[slaves]
xxx.xxx.xxx.xx1 ansible_ssh_user=slave-node-one  ansible_ssh_pass=slave-node-one  ansible_become=yes  ansible_become_pass=slave-node-one
xxx.xxx.xxx.xx2 ansible_ssh_user=slave-node-two  ansible_ssh_pass=slave-node-two  ansible_become=yes  ansible_become_pass=slave-node-two

License

BSD

Author Information

@arsalen (github, medium, linkedin)