kubespray/roles/kubernetes/master/tasks/kubeadm-upgrade.yml

---
- name: kubeadm | Upgrade first master
  command: >-
    timeout -k 600s 600s
    {{ bin_dir }}/kubeadm
    upgrade apply -y {{ kube_version }}
    --config={{ kube_config_dir }}/kubeadm-config.yaml
    --ignore-preflight-errors=all
    --allow-experimental-upgrades
    --allow-release-candidate-upgrades
    --etcd-upgrade=false
    {{ (kubeadm_output.stdout is version('v1.16.0', '>=')) | ternary('--certificate-renewal=true', '') }}
    --force
  register: kubeadm_upgrade
  # Retry is because upload config sometimes fails
  retries: 3
  when: inventory_hostname == groups['kube-master']|first
  failed_when: kubeadm_upgrade.rc != 0 and "field is immutable" not in kubeadm_upgrade.stderr
  notify: Master | restart kubelet

# FIXME: https://github.com/kubernetes/kubeadm/issues/1498 remove stdout_lines
# check after issue is fixed
- name: kubeadm | Upgrade other masters
  command: >-
    timeout -k 600s 600s
    {{ bin_dir }}/kubeadm
    upgrade apply -y {{ kube_version }}
    --config={{ kube_config_dir }}/kubeadm-config.yaml
    --ignore-preflight-errors=all
    --allow-experimental-upgrades
    --allow-release-candidate-upgrades
    --etcd-upgrade=false
    {{ (kubeadm_output.stdout is version('v1.16.0', '>=')) | ternary('--certificate-renewal=true', '') }}
    --force
  register: kubeadm_upgrade
  when: inventory_hostname != groups['kube-master']|first
  failed_when:
    - kubeadm_upgrade.rc != 0
    - '"field is immutable" not in kubeadm_upgrade.stderr'
    - kubeadm_upgrade.stdout_lines | length > 1
  notify: Master | restart kubelet

- name: kubeadm | clean kubectl cache to refresh api types
  file:
    path: "{{ item }}"
    state: absent
  with_items:
    - /root/.kube/cache
    - /root/.kube/http-cache

# FIXME: https://github.com/kubernetes/kubeadm/issues/1318
- name: kubeadm | scale down coredns replicas to 0 if not using coredns dns_mode
  command: >-
    {{ bin_dir }}/kubectl
    --kubeconfig /etc/kubernetes/admin.conf
    -n kube-system
    scale deployment/coredns --replicas 0
  register: scale_down_coredns
  retries: 6
  delay: 5
  until: scale_down_coredns is succeeded
  run_once: yes
  when:
    - kubeadm_scale_down_coredns_enabled
    - dns_mode not in ['coredns', 'coredns_dual']
  changed_when: false