Add capability to use swap, requires Kube 1.22 (#8241)

* Alpha-NodeSwap: allow nodes to use swap

* CI: Add Fedora 35 with experimental swap job

roles/kubernetes/node/templates/kubelet-config.v1beta1.yaml.j2

@@ -106,3 +106,7 @@ eventRecordQPS: {{ kubelet_event_record_qps }}
 shutdownGracePeriod: {{ kubelet_shutdown_grace_period }}
 shutdownGracePeriodCriticalPods: {{ kubelet_shutdown_grace_period_critical_pods }}
 {% endif %}
+{% if not kubelet_fail_swap_on|default(true) %}
+memorySwap:
+  swapBehavior: {{ kubelet_swap_behavior|default("LimitedSwap") }}
+{% endif %}

roles/kubernetes/preinstall/tasks/0010-swapoff.yml

@@ -13,11 +13,17 @@
   command: /sbin/swapon -s
   register: swapon
   changed_when: no
+
 - name: Disable swap
   command: /sbin/swapoff -a
-  when: swapon.stdout
+  when:
+    - swapon.stdout
+    - kubelet_fail_swap_on | default(True)
   ignore_errors: "{{ ansible_check_mode }}"  # noqa ignore-errors
 
 - name: Disable swapOnZram for Fedora
   command: touch /etc/systemd/zram-generator.conf
-  when: swapon.stdout and ansible_distribution in ['Fedora']
+  when:
+    - swapon.stdout
+    - ansible_distribution in ['Fedora']
+    - kubelet_fail_swap_on | default(True)