boot.yml

---
- hosts: master
  vars:
    init_token: foobar.1234
  tasks:
  - name: Start Docker
    service: enabled=yes state=started name=docker
    become: true
  - name: Start Kubelet
    service: enabled=yes state=started name=kubelet
    become: true
  - name: Run Kubeadm master
    command: kubeadm init --token {{ init_token }} 
    become: true

- hosts: nodes
  vars:
    init_token: foobar.1234
  tags: nodes
  tasks:
  - name: Start Docker
    service: enabled=yes state=started name=docker
    become: true
  - name: Start Kubelet
    service: enabled=yes state=started name=kubelet
    become: true
  - name: Debug master_node IP
    debug: msg='master node IP is {{ hostvars['master_node'].ansible_default_ipv4.address }}'
  - name: Run Kubeadm nodes
    command: kubeadm join --token {{ init_token }} {{ hostvars['master_node'].ansible_default_ipv4.address }}
    become: true