Swap file. Lint.

Author: sdarwin

.yamllint

@@ -1,6 +1,14 @@
 ---
 extends: default
 rules:
+  braces:
+    max-spaces-inside: 1
+  comments-indentation: false
+  comments:
+    min-spaces-from-content: 1
+  octal-values:
+    forbid-explicit-octal: true
+    forbid-implicit-octal: true
   line-length:
     max: 400
     level: warning

defaults/main.yml

@@ -482,3 +482,9 @@ elasticsearch_heap_size_max: 2g
 # used by Django, not necessarily by elasticsearch itself:
 elasticsearch_index_name: mailman
 elasticsearch_url: "http://127.0.0.1:9200/"
+
+swap_configure: true   # manage the swap or not
+swap_enable: true
+swap_file_path: /swapfile
+swap_file_size_mb: 4000
+swappiness: 1

tasks/elasticsearch.yml

@@ -28,7 +28,7 @@
     dest: "{{ item }}"
     owner: root
     group: elasticsearch
-    mode: 0660
+    mode: '0660'
   with_items:
     - /etc/elasticsearch/elasticsearch.yml
     - /etc/elasticsearch/jvm.options.d/heap.options

tasks/main.yml

@@ -1,4 +1,6 @@
 ---
+- name: Include swap configuration
+  ansible.builtin.include_tasks: swap.yml
 
 - name: Include server configuration tasks
   ansible.builtin.include_tasks: server.yml

tasks/swap.yml

@@ -0,0 +1,106 @@
+---
+# From https://stackoverflow.com/questions/24765930/add-swap-memory-with-ansible
+- name: Configure swap
+  when: swap_configure | bool | default(false)
+  block:
+
+    - name: Check if swap file exists
+      ansible.builtin.stat:
+        path: "{{ swap_file_path }}"
+        get_checksum: false
+        get_md5: false
+        get_mime: false
+        get_attributes: false
+      register: swap_file_check
+      changed_when: false
+
+    - name: Check if swap is on
+      ansible.builtin.shell:
+        set -o pipefail;
+        swapon --show | grep {{ swap_file_path }}
+      args:
+        executable: /bin/bash
+      register: swap_enabled
+      changed_when: false
+      failed_when: false
+
+    - name: Disable swap
+      ansible.builtin.command: swapoff {{ swap_file_path }}
+      register: swap_disabled
+      changed_when: true
+      when: >
+        swap_file_check.stat.exists
+        and swap_enabled.rc == 0
+        and (not swap_enable
+             or (swap_enable and swap_file_check.stat.size != (swap_file_size_mb * 1024 * 1024)))
+
+    - name: Delete the swap file
+      ansible.builtin.file:
+        path: "{{ swap_file_path }}"
+        state: absent
+      when: not swap_enable
+
+    - name: Configure swap
+      when: swap_enable|bool
+      block:
+
+        - name: Create or change the size of swap file
+          ansible.builtin.command: dd if=/dev/zero of={{ swap_file_path }} count={{ swap_file_size_mb }} bs=1MiB
+          register: swap_file_created
+          changed_when: true
+          when: >
+            not swap_file_check.stat.exists
+            or swap_file_check.stat.size != (swap_file_size_mb * 1024 * 1024)
+
+        - name: Change swap file permissions
+          ansible.builtin.file:
+            path: "{{ swap_file_path }}"
+            owner: root
+            group: root
+            mode: '0600'
+
+        - name: Check if swap is formatted
+          ansible.builtin.shell:
+            set -o pipefail;
+            file {{ swap_file_path }} | grep 'swap file'
+          args:
+            executable: /bin/bash
+          register: swap_file_is_formatted
+          changed_when: false
+          failed_when: false
+
+        - name: Debugger1
+          ansible.builtin.debug:
+            var: swap_file_is_formatted
+
+        - name: Debugger2
+          ansible.builtin.debug:
+            var: swap_file_created
+
+        - name: Format swap file if it's not formatted
+          ansible.builtin.command: mkswap {{ swap_file_path }}
+          when: swap_file_is_formatted.rc > 0 or swap_file_created.changed
+          changed_when: true
+
+        - name: Add swap entry to fstab
+          ansible.posix.mount:
+            path: none
+            src: "{{ swap_file_path }}"
+            fstype: swap
+            opts: defaults
+            passno: 0
+            dump: 0
+            state: present
+
+        - name: Turn on swap
+          ansible.builtin.command: swapon -a
+          when: swap_enable
+          changed_when: false
+          # original logic from article. However, let's start it every time.
+          # when: swap_enabled.rc != 0 and swap_disabled.changed
+
+        - name: Configure swappiness
+          ansible.posix.sysctl:
+            name: vm.swappiness
+            value: "{{ swappiness }}"
+            state: present