Use Ansible mount module options to modify /etc/fstab

ntools/one-m/ansible/roles/db_storage/tasks/edit_etc_fstab.py

@@ -1,23 +0,0 @@
-"""
-This Python 3 script reads the /etc/fstab file line by line
-and writes a new file /tmp/fstab line by line.
-If a line contains the string '/dev/xvdp', it replaces that
-line with:
-/dev/xvdp /data ext4 defaults,nofail,nobootwait 0 2
-It then:
-- moves /etc/fstab to /etc/old_fstab
-- moves /tmp/fstab to /etc/fstab
-"""
-
-import shutil
-
-with open('/tmp/fstab', 'a') as tmp_fstab:
-    with open('/etc/fstab') as f:
-        for line in f:
-            if '/dev/xvdp' in line:
-                tmp_fstab.write('/dev/xvdp /data ext4 defaults,nofail,nobootwait 0 2\n')
-            else:
-                tmp_fstab.write(line)
-
-shutil.move('/etc/fstab', '/etc/old_fstab')
-shutil.move('/tmp/fstab', '/etc/fstab')

ntools/one-m/ansible/roles/db_storage/tasks/main.yml

@@ -8,33 +8,22 @@
   filesystem: fstype=ext4 dev=/dev/xvdp
   become: true
 
-# Note that this also modifies /etc/fstab so the mount will persist through a crash
-- name: Ensure /data dir exists and is mounted on /dev/xvdp + update /etc/fstab
-  mount: name=/data src=/dev/xvdp fstype=ext4 state=mounted
+# Note that this also modifies /etc/fstab so the mount will persist through a crash.
+# To better understand the /etc/fstab fields/columns, see:
+# http://man7.org/linux/man-pages/man5/fstab.5.html
+# https://tinyurl.com/jmmsyon = the soure code of the mount module
+- name: Ensure /data dir exists and is mounted + update /etc/fstab
+  mount:
+    name=/data
+    src=/dev/xvdp
+    fstype=ext4
+    opts="defaults,nofail,nobootwait"
+    dump=0
+    passno=2
+    state=mounted
   become: true
 
-# After allowing the above to proceed,
-# I did "cat /etc/fstab" and got:
-# LABEL=cloudimg-rootfs	/	 ext4	defaults,discard	0 0
-# /dev/xvdp /data ext4 defaults 0 0
-
-# Let's change "defaults 0 0" to "defaults,nofail,nobootwait 0 2"
-
-- name: Ensure any old edit_etc_fstab.py file is deleted
-  file: name=/tmp/edit_etc_fstab.py state=absent
-
-- name: Copy local Python script edit_etc_fstab.py to the remote host
-  copy: src={{role_path}}/tasks/edit_etc_fstab.py dest=/tmp/edit_etc_fstab.py
-
-- name: Run edit_etc_fstab.py using Python 3
-  shell: /usr/bin/python3 /tmp/edit_etc_fstab.py
-  become: true
-
-- name: Ensure /tmp/edit_etc_fstab.py is deleted
-  file: name=/tmp/edit_etc_fstab.py state=absent
-
 # Modify the I/O scheduler? Is that even a good idea?
 # Must do this in /sys/block/xvdp/queue/scheduler
 # and also with grub (so the I/O scheduler stays changed on reboot)
 # Example: https://gist.github.com/keithchambers/80b60559ad83cebf1672
-