playbook-k8s-master-cluster.yml

---

# Play 1
#------------------------
- name: Install all prerequisites, the CRI (containerd), and Kubernetes components (kubeadm, kubectl, kubelet)
  hosts: all
  become: yes
  tasks:
  
  - name: Run the prerequisite setup
    include: tasks-shared-setup.yml


# Play 2
#------------------------
- name: Install kube-vip, and initialize a cluster onto the first Master node
  hosts: first-master-node
  become: yes
  vars_files:
  - /vars/external_vars.yml
  tasks:
  
  - name: Pull the image for kube-vip
    shell: ctr image pull docker.io/plndr/kube-vip:0.3.4

  - name: Generate the static pod yaml file for kube-vip and place into /etc/kubernetes/manifests
    shell: ctr run --rm --net-host docker.io/plndr/kube-vip:0.3.4 vip /kube-vip manifest pod --interface eth0 --address {{kube_vip}} --controlplane --arp --leaderElection | tee /etc/kubernetes/manifests/vip.yaml
    args:
      creates: "/etc/kubernetes/manifests/vip.yaml"

  # Source: https://kubernetes.io/docs/setup/production-environment/tools/kubeadm/create-cluster-kubeadm/

  - name: Create the file kubeadm-config.yaml in /tmp/
    ansible.builtin.copy:
      content: |
        kind: ClusterConfiguration
        apiVersion: kubeadm.k8s.io/v1beta2
        controlPlaneEndpoint: "{{kube_vip}}:6443"
        networking:
          podSubnet: "{{pod_subnet}}"
        ---
        kind: KubeletConfiguration
        apiVersion: kubelet.config.k8s.io/v1beta1
        cgroupDriver: systemd
      dest: /tmp/kubeadm-config.yaml
  
  - name: Initialize the cluster using the config file
    shell: |
      kubeadm init --config /tmp/kubeadm-config.yaml --upload-certs
      touch /etc/kubernetes/ansible-installed-k8s
    args:
      creates: /etc/kubernetes/ansible-installed-k8s

  - name: Configure the kube config file
    shell: |
      mkdir -p /home/{{user}}/.kube
      cp -i /etc/kubernetes/admin.conf /home/{{user}}/.kube/config
      chown $(id -u {{user}}):$(id -g {{user}}) /home/{{user}}/.kube/config
    args:
      creates: "/home/{{user}}/.kube/config"

  - name: Install calico pod network
    shell: |
      kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml --kubeconfig /etc/kubernetes/admin.conf
      touch /etc/kubernetes/ansible-installed-calico
    args:
      creates: /etc/kubernetes/ansible-installed-calico

  # Source: https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-join/

  - name: Generate the command to join a node and assign it to a variable
    shell: kubeadm token create --print-join-command
    register: join_command

  - name: Generate the certificate key and assign it to a variable
    shell: kubeadm init phase upload-certs --upload-certs
    register: certificate_key

  - name: Copy the join command for a Master node to a local file
    ansible.builtin.copy:
      content: "{{ join_command.stdout_lines[0] }} --control-plane --certificate-key {{ certificate_key.stdout_lines[2] }}"
      dest: "./join-command-master"
    delegate_to: 127.0.0.1

  - name: Copy the join command for a Worker node to a local file
    ansible.builtin.copy:
      content: "{{ join_command.stdout_lines[0] }}"
      dest: "./join-command-worker"
    delegate_to: 127.0.0.1


# Play 3
#------------------------
- name: Join the other Master nodes to the cluster
  hosts: other-master-nodes
  become: yes
  vars_files:
  - /vars/external_vars.yml
  tasks:

  - name: Copy the join command to the other Master nodes
    ansible.builtin.copy:
      src: join-command-master
      dest: /tmp/join-command-master.sh
      mode: '0777'

  - name: Join the other Master nodes to cluster
    shell: |
      sh /tmp/join-command-master.sh
      touch /etc/kubernetes/ansible-installed-k8s
    args:
      creates: /etc/kubernetes/ansible-installed-k8s

  # Due to an oddity with kubeadm, join additional Master nodes first, then configure the kube-vip manifest file
  - name: Pull the image for kube-vip
    shell: ctr image pull docker.io/plndr/kube-vip:0.3.4

  - name: Generate the static pod yaml file for kube-vip and place in /etc/kubernetes/manifests
    shell: ctr run --rm --net-host docker.io/plndr/kube-vip:0.3.4 vip /kube-vip manifest pod --interface eth0 --address {{kube_vip}} --controlplane --arp --leaderElection | tee /etc/kubernetes/manifests/vip.yaml
    args:
      creates: "/etc/kubernetes/manifests/vip.yaml"


# Play 4
#------------------------
- name: Join the Worker nodes to the cluster
  hosts: worker-nodes
  become: yes
  tasks:

  - name: Copy the join command to the Worker node
    ansible.builtin.copy:
      src: join-command-worker
      dest: /tmp/join-command-worker.sh
      mode: '0777'

  - name: Join the Worker nodes to cluster
    shell: |
      sh /tmp/join-command-worker.sh
      touch /etc/kubernetes/ansible-installed-k8s
    args:
      creates: /etc/kubernetes/ansible-installed-k8s