added roles and playbooks for k3s

roles/raspberrypi/tasks/prereq/CentOS.yml

@@ -0,0 +1,8 @@
+---
+- name: Enable cgroup via boot commandline if not already enabled for Centos
+  lineinfile:
+    path: /boot/cmdline.txt
+    backrefs: yes
+    regexp: '^((?!.*\bcgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory\b).*)$'
+    line: '\1 cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory'
+  notify: reboot

roles/raspberrypi/tasks/prereq/Raspbian.yml

@@ -0,0 +1,25 @@
+---
+- name: Activating cgroup support
+  lineinfile:
+    path: /boot/cmdline.txt
+    regexp: '^((?!.*\bcgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory\b).*)$'
+    line: '\1 cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory'
+    backrefs: true
+  notify: reboot
+
+- name: Flush iptables before changing to iptables-legacy
+  iptables:
+    flush: true
+  changed_when: false   # iptables flush always returns changed
+
+- name: Changing to iptables-legacy
+  alternatives:
+    path: /usr/sbin/iptables-legacy
+    name: iptables
+  register: ip4_legacy
+
+- name: Changing to ip6tables-legacy
+  alternatives:
+    path: /usr/sbin/ip6tables-legacy
+    name: ip6tables
+  register: ip6_legacy

roles/raspberrypi/tasks/prereq/Ubuntu.yml

@@ -0,0 +1,8 @@
+---
+- name: Enable cgroup via boot commandline if not already enabled for Ubuntu on a Raspberry Pi
+  lineinfile:
+    path: /boot/firmware/cmdline.txt
+    backrefs: yes
+    regexp: '^((?!.*\bcgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory\b).*)$'
+    line: '\1 cgroup_enable=cpuset cgroup_memory=1 cgroup_enable=memory'
+  notify: reboot

roles/raspberrypi/tasks/prereq/default.yml

@@ -0,0 +1 @@
+---