Use a variable for standardizing kubectl invocation (#8329)

* Add kubectl variable

* Replace kubectl usage by kubectl variable in roles

* Remove redundant --kubeconfig on kubectl usage

* Replace unecessary shell usage with command

roles/remove-node/post-remove/tasks/main.yml

@@ -1,6 +1,6 @@
 ---
 - name: Delete node
-  command: "{{ bin_dir }}/kubectl delete node {{ kube_override_hostname|default(inventory_hostname) }}"
+  command: "{{ kubectl }} delete node {{ kube_override_hostname|default(inventory_hostname) }}"
   delegate_to: "{{ groups['kube_control_plane']|first }}"
   when: inventory_hostname in groups['k8s_cluster']
   retries: 10

roles/remove-node/pre-remove/tasks/main.yml

@@ -1,7 +1,7 @@
 ---
 - name: remove-node | List nodes
   command: >-
-    {{ bin_dir }}/kubectl get nodes -o go-template={% raw %}'{{ range .items }}{{ .metadata.name }}{{ "\n" }}{{ end }}'{% endraw %}
+    {{ kubectl }} get nodes -o go-template={% raw %}'{{ range .items }}{{ .metadata.name }}{{ "\n" }}{{ end }}'{% endraw %}
   register: nodes
   delegate_to: "{{ groups['kube_control_plane']|first }}"
   changed_when: false
@@ -9,7 +9,7 @@
 
 - name: remove-node | Drain node except daemonsets resource  # noqa 301
   command: >-
-    {{ bin_dir }}/kubectl --kubeconfig {{ kube_config_dir }}/admin.conf drain
+    {{ kubectl }} drain
       --force
       --ignore-daemonsets
       --grace-period {{ drain_grace_period }}

roles/remove-node/remove-etcd-node/tasks/main.yml

@@ -1,8 +1,8 @@
 ---
 - name: Lookup node IP in kubernetes
-  shell: >-
-    {{ bin_dir }}/kubectl get nodes {{ node }}
-    -o jsonpath='{range.status.addresses[?(@.type=="InternalIP")]}{.address}{"\n"}{end}'
+  command: >
+    {{ kubectl }} get nodes {{ node }}
+    -o jsonpath={range.status.addresses[?(@.type=="InternalIP")]}{.address}{"\n"}{end}
   register: remove_node_ip
   when:
     - inventory_hostname in groups['etcd']