Add cgroup checks

tasks/validate/environment/remote/cgroups.yml

@@ -0,0 +1,15 @@
+---
+
+- name: Check if {{ cgroup.name }} cgroup is enabled
+  ansible.builtin.command: grep -E "^{{ cgroup.name }}\s+.*\s+1$" /proc/cgroups
+  failed_when: false
+  changed_when: false
+  register: k3s_check_cgroup_option
+
+- name: Fail if {{ cgroup.name }} cgroup is not enabled
+  ansible.builtin.assert:
+    that:
+      - k3s_check_cgroup_option.rc == 0
+    fail_msg: |
+      {{ cgroup.name }} cgroup disabled. {{ cgroup.documentation }}
+    success_msg: "{{ cgroup.name }} cgroup enabled."

tasks/validate/pre-flight.yml

@@ -13,12 +13,20 @@
     - not k3s_skip_validation
     - not k3s_skip_env_checks
 
+- include_tasks: environment/remote/cgroups.yml
+  loop: "{{ k3s_cgroup_subsys }}"
+  loop_control:
+    loop_var: cgroup
+  when:
+    - not k3s_skip_validation
+    - not k3s_skip_env_checks
+
 - include_tasks: environment/remote/packages.yml
   loop: "{{ k3s_check_packages }}"
   loop_control:
     loop_var: package
   when:
-    - k3s_skip_validation
+    - not k3s_skip_validation
     - not k3s_skip_env_checks
 
 - include_tasks: environment/local/issue-data.yml

vars/main.yml

@@ -143,3 +143,13 @@ k3s_deprecated_config:
   - setting: docker
     correction: "docker: false"
     when: 1.20.0
+
+k3s_cgroup_subsys:
+  - name: memory
+    documentation: |
+      If you are running on a Raspberry Pi, see:
+      https://rancher.com/docs/k3s/latest/en/advanced/#enabling-cgroups-for-raspbian-buster
+  - name: cpuset
+    documentation: |
+      If you are running Alpine Linux, see:
+      https://rancher.com/docs/k3s/latest/en/advanced/#additional-preparation-for-alpine-linux-setup