integration-playbook: Idempotent Swapping

If the playbook is run multiple times or a host already has
swap configured, re-adding swap over the existing file
will cause untold problems.  Also, it will not persist across
reboots unless added to fstab.

Avoid this by checking if any swap is active. If not
create a unique swapfile and format it.  Then enable
it to persist across reboots.

Signed-off-by: Chris Evich <cevich@redhat.com>

contrib/test/integration/swap.yml

@@ -0,0 +1,42 @@
+---
+
+- name: Obtain current state of swap
+  command: swapon --noheadings --show=NAME
+  register: swapon
+
+- name: Setup swap if none already, to prevent kernel firing off the OOM killer
+  block:
+
+    - name: A unique swapfile path is generated
+      command: mktemp --tmpdir=/root swapfile_XXX
+      register: swapfilepath
+
+    - name: Swap file path is buffered
+      set_fact:
+        swapfilepath: '{{ swapfilepath.stdout | trim }}'
+
+    - name: Set swap file permissions
+      file:
+        path: "{{ swapfilepath }}"
+        owner: root
+        group: root
+        mode: 0600
+
+    - name: Swapfile padded to swapfile_size & timed to help debug any performance problems
+      shell: 'time dd if=/dev/zero of={{ swapfilepath }} bs={{ swapfileGB }}M count=1024'
+
+    - name: Swap file is formatted
+      command: 'mkswap {{ swapfilepath }}'
+
+    - name: Write swap entry in fstab
+      mount:
+        path: none
+        src: "{{ swapfilepath }}"
+        fstype: swap
+        opts: sw
+        state: present
+
+    - name: Mount swap
+      command: "swapon -a"
+
+  when: not (swapon.stdout_lines | length)

contrib/test/integration/system.yml

@@ -72,13 +72,8 @@
   async: 600
   poll: 10
 
-- name: Setup swap to prevent kernel firing off the OOM killer
-  shell: |
-    truncate -s 8G /root/swap && \
-    export SWAPDEV=$(losetup --show -f /root/swap | head -1) && \
-    mkswap $SWAPDEV && \
-    swapon $SWAPDEV && \
-    swapon --show
+- name: Check / setup swap
+  include: "swap.yml"
 
 - name: ensure directories exist as needed
   file:

contrib/test/integration/vars.yml

@@ -1,5 +1,8 @@
 ---
 
+# When swap setup is necessary, make it this size
+swapfileGB: 8
+
 # For results.yml Paths use rsync 'source' conventions
 artifacts: "/tmp/artifacts"  # Base-directory for collection
 crio_integration_filepath: "{{ artifacts }}/testout.txt"