Improve control plane scale flow (#13)

* Added version 1.20.10 of K8s

* Setting first_kube_control_plane to a existing one

* Setting first_kube_control_plane to a existing one

roles/kubernetes/control-plane/tasks/define-first-kube-control.yml

@@ -0,0 +1,16 @@
+- name: Check which kube-control nodes are already members of the cluster
+  shell: "{{ bin_dir }}/kubectl get nodes --selector=node-role.kubernetes.io/control-plane -o json"
+  register: kube_control_planes_raw
+  ignore_errors: yes
+
+- name: Set fact joined_control_panes
+  set_fact:
+    joined_control_planes: "{{ ((kube_control_planes_raw.stdout| from_json)['items'])| default([]) | map (attribute='metadata') | map (attribute='name') | list }}"
+  delegate_to: item
+  with_items: groups['kube_control_plane']
+  when: kube_control_planes_raw is succeeded
+  run_once: yes
+
+- name: Set fact first_kube_control_plane
+  set_fact:
+    first_kube_control_plane: "{{ joined_control_planes|default([]) | first | default(groups['kube_control_plane']|first) }}"

roles/kubernetes/control-plane/tasks/kubeadm-secondary.yml

@@ -18,7 +18,7 @@
     --upload-certs
   register: kubeadm_upload_cert
   when:
-    - inventory_hostname == groups['kube_control_plane']|first
+    - inventory_hostname == first_kube_control_plane
 
 - name: Parse certificate key if not set
   set_fact:
@@ -35,7 +35,7 @@
     mode: 0640
     backup: yes
   when:
-    - inventory_hostname != groups['kube_control_plane']|first
+    - inventory_hostname != first_kube_control_plane
     - not kubeadm_already_run.stat.exists
 
 - name: Wait for k8s apiserver
@@ -64,5 +64,5 @@
   throttle: 1
   until: kubeadm_join_control_plane is succeeded
   when:
-    - inventory_hostname != groups['kube_control_plane']|first
+    - inventory_hostname != first_kube_control_plane
     - kubeadm_already_run is not defined or not kubeadm_already_run.stat.exists

roles/kubernetes/control-plane/tasks/kubeadm-setup.yml

@@ -131,7 +131,7 @@
   # Retry is because upload config sometimes fails
   retries: 3
   until: kubeadm_init is succeeded or "field is immutable" in kubeadm_init.stderr
-  when: inventory_hostname == groups['kube_control_plane']|first and not kubeadm_already_run.stat.exists
+  when: inventory_hostname == first_kube_control_plane and not kubeadm_already_run.stat.exists
   failed_when: kubeadm_init.rc != 0 and "field is immutable" not in kubeadm_init.stderr
   environment:
     PATH: "{{ bin_dir }}:{{ ansible_env.PATH }}"
@@ -151,7 +151,7 @@
     {{ bin_dir }}/kubeadm --kubeconfig /etc/kubernetes/admin.conf token create {{ kubeadm_token }}
   changed_when: false
   when:
-    - inventory_hostname == groups['kube_control_plane']|first
+    - inventory_hostname ==  first_kube_control_plane
     - kubeadm_token is defined
     - kubeadm_refresh_token
   tags:
@@ -164,7 +164,7 @@
   retries: 5
   delay: 5
   until: temp_token is succeeded
-  delegate_to: "{{ groups['kube_control_plane'] | first }}"
+  delegate_to: "{{ first_kube_control_plane }}"
   when: kubeadm_token is not defined
   tags:
     - kubeadm_token
@@ -188,7 +188,7 @@
 # FIXME(mattymo): from docs: If you don't want to taint your control-plane node, set this field to an empty slice, i.e. `taints: {}` in the YAML file.
 - name: kubeadm | Remove taint for master with node role
   command: "{{ bin_dir }}/kubectl --kubeconfig {{ kube_config_dir }}/admin.conf taint node {{ inventory_hostname }} {{ item }}"
-  delegate_to: "{{ groups['kube_control_plane'] | first }}"
+  delegate_to: "{{ first_kube_control_plane }}"
   with_items:
     - "node-role.kubernetes.io/master:NoSchedule-"
     - "node-role.kubernetes.io/control-plane:NoSchedule-"

roles/kubernetes/control-plane/tasks/kubeadm-upgrade.yml

@@ -23,7 +23,7 @@
   # Retry is because upload config sometimes fails
   retries: 3
   until: kubeadm_upgrade.rc == 0
-  when: inventory_hostname == groups['kube_control_plane']|first
+  when: inventory_hostname == first_kube_control_plane
   failed_when: kubeadm_upgrade.rc != 0 and "field is immutable" not in kubeadm_upgrade.stderr
   environment:
     PATH: "{{ bin_dir }}:{{ ansible_env.PATH }}"
@@ -40,7 +40,7 @@
     --etcd-upgrade={{ etcd_kubeadm_enabled | bool | lower }}
     --force
   register: kubeadm_upgrade
-  when: inventory_hostname != groups['kube_control_plane']|first
+  when: inventory_hostname != first_kube_control_plane
   failed_when:
     - kubeadm_upgrade.rc != 0
     - '"field is immutable" not in kubeadm_upgrade.stderr'

roles/kubernetes/control-plane/tasks/main.yml

@@ -3,6 +3,9 @@
   tags:
     - k8s-pre-upgrade
 
+- name: Define nodes already joined to existing cluster and first_kube_master
+  import_tasks: define-first-kube-control.yml
+
 - name: Create webhook token auth config
   template:
     src: webhook-token-auth-config.yaml.j2