Really fix idempotence for Flannel tasks, and get CentOS mostly working.

README.md

@@ -22,9 +22,9 @@ Available variables are listed below, along with default values (see `defaults/m
 
 TODO.
 
-    kubernetes_allow_swap: False
+    kubernetes_kubelet_extra_args: ""
 
-TODO.
+TODO. Example: `"--fail-swap-on=false --cgroup-driver=systemd"`.
 
     kubernetes_allow_pods_on_master: True
 

defaults/main.yml

@@ -9,7 +9,7 @@ kubernetes_packages:
   - name: kubernetes-cni
     state: present
 
-kubernetes_allow_swap: False
+kubernetes_kubelet_extra_args: ""
 
 kubernetes_allow_pods_on_master: True
 kubernetes_enable_web_ui: True

tasks/main.yml

@@ -15,14 +15,14 @@
   notify: restart kubelet
   with_items: "{{ kubernetes_packages }}"
 
-- name: Allow kubelet to run with swap enabled (if configured).
+- name: Configure KUBELET_EXTRA_ARGS.
   lineinfile:
     path: /etc/systemd/system/kubelet.service.d/10-kubeadm.conf
-    line: 'Environment="KUBELET_EXTRA_ARGS=--fail-swap-on=false"'
-    regexp: 'Environment="KUBELET_EXTRA_ARGS=--fail-swap-on.+'
+    line: 'Environment="KUBELET_EXTRA_ARGS={{ kubernetes_kubelet_extra_args }}"'
+    regexp: 'Environment="KUBELET_EXTRA_ARGS='
     insertafter: '^Environment='
     state: present
-  when: kubernetes_allow_swap
+  notify: restart kubelet
 
 - name: Ensure kubelet is started and enabled at boot.
   service:
@@ -66,10 +66,8 @@
   with_items:
     - kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
     - kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/master/Documentation/k8s-manifests/kube-flannel-rbac.yml
-  register: flannel_networking_result
-  changed_when: >
-    ('unchanged' not in flannel_networking_result.stdout)
-    or ('configured' not in flannel_networking_result.stdout)
+  register: flannel_result
+  changed_when: "'created' in flannel_result.stdout"
 
 # TODO: Check if taint exists with something like `kubectl describe nodes`
 # instead of using kubernetes_init_stat.stat.exists check.

tasks/setup-RedHat.yml

@@ -23,4 +23,5 @@
 - name: Make cache if Kubernetes GPG key changed.
   command: "yum -q makecache -y --disablerepo='*' --enablerepo='kubernetes'"
   when: kubernetes_rpm_key is changed
-  warn: no
+  args:
+    warn: no

tests/test.yml

@@ -2,7 +2,8 @@
 - hosts: all
 
   vars:
-    kubernetes_allow_swap: True
+    # Allow swap in test environments (hard to control in some Docker envs).
+    kubernetes_kubelet_extra_args: "--fail-swap-on=false"
 
   pre_tasks:
     - name: Update apt cache.
@@ -14,6 +15,11 @@
 
     - action: setup
 
+    - name: Use cgroupfs cgroup driver instead of systemd (Red Hat).
+      set_fact:
+        kubernetes_kubelet_extra_args: "--fail-swap-on=false --cgroup-driver=cgroupfs"
+      when: ansible_os_family == 'RedHat'
+
   roles:
     - geerlingguy.docker
     - role_under_test