use docker repository to install on CentOS

roles/kubernetes/preinstall/tasks/main.yml

@@ -79,11 +79,10 @@
   changed_when: False
 
 - name: Install epel-release on RedHat/CentOS
-  action:
-    module: "{{ ansible_pkg_mgr }}"
-    name: "epel-release"
-    state: latest
-  when: ansible_distribution in ['CentOS', 'RedHat']
+  command: rpm -ivh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
+  when: ansible_distribution in ["CentOS","RedHat"] and
+        ansible_distribution_major_version >= 7
+  changed_when: False
 
 - name: Install packages requirements
   action:

roles/kubernetes/secrets/tasks/check-certs.yml

@@ -2,7 +2,7 @@
 - name: "Check certs | check if the certs have already been generated on first master"
   stat:
     path: "{{ kube_cert_dir }}/ca.pem"
-  delegate_to: groups['kube-master'][0]
+  delegate_to: "{{groups['kube-master'][0]}}"
   register: kubecert_master
   run_once: true