adding an fstab option using Ansible - regex

Question

I am trying to add nodev to my /etc/fstab file. I am using the Ansible command below but with no luck. My issue lies with the regular expression, I'm not a pro at regex.
- name: Add nodev to /etc/fstab
lineinfile:
dest=/etc/fstab
backup=yes
backrefs=yes
state=present
regexp='(^/dev[\w/_-]+(\s+(?!nodev)[\w,]+)*)'
line='\1,nodev'
One of the lines from /etc/fstab that I am trying to add nodev is:
/dev/mapper/ex_sys-ex_home /home /ext4 rw,exec,auto,nouser,sync 1 2

Answer 1

While this may not be the most elegant answer, it worked for me.
- name: Ensure fstab uses nodev
mount:
name: "{{ item.mount }}"
src: "{{ item.device }}"
fstype: "{{ item.fstype }}"
opts: "{{ item.options }},nodev"
state: present
with_items: ansible_mounts
when: item.options.find(",") >= 0 and item.options.find("nodev") == -1

Answer 2

Inspired by Joe's answer I made this version which will add a single option to a specific line in /etc/fstab if it isn't there already. This will also keep any other options the line already had.
main.yml
- import_tasks: fstab-opt-present.yml point=/home opt=nodev
fstab-opt-present.yml
- name: '/etc/fstab: Set opt "{{ opt }}" for mount point {{ point }}'
lineinfile:
path: /etc/fstab
backup: yes
backrefs: yes
regexp: '^(\S+\s+{{ point }}\s+\S+\s+)(?!(?:\S*,)?{{ opt }}(?:,\S*)?\s+)(\S+)(\s+.+)$'
line: '\1{{ opt }},\2\3'
register: fstab
- name: 'If {{ point }} changed, remount'
command: 'mount {{ point }} -o remount'
when: fstab.changed
https://regex101.com/ is a really helpful tool for building and testing these kind of regexps. Just enable the "multiline" option there and open the "Substitution" panel and you can even paste in your /etc/fstab and see which lines your regex will match and what it will do to them. Just remember to use real values instead of the Ansible variables {{ point }} etc. when testing there

Answer 3

We've developed a 3rd-party ansible module to add, set or remove mount options. Check it out!
- mountopts:
name: /
option: nodev
https://github.com/Uberspace/ansible-mountopts

Answer 4

I wanted to state that there seems to be a new ansible module which covers all this much more easily:
https://docs.ansible.com/ansible/latest/modules/mount_module.html

Answer 5

Tested & works fine
- name: Set nodev option
replace:
path: /etc/fstab
backup: yes
regexp: '^(\S+\s+)(\/\S+)(\s+)((?:ext4|xfs)\s+)(?!(?:\S*,)?nodev(?:,\S*)?\s+)(\S+)(\s+.+)$'
replace: '\1\2 \4 \5,nodev \6'
It excludes adding nodev to /(root), sets only to ext4 and xfs filesystem. doesn't add to temp filesystems.
Note: while you test regexp101, make sure to select python

Answer 6

Landed here looking for an answer, wound up rolling my own for my use case:
main.yml
- include: fstab-opts.yml point=/tmp opts=noexec,nodev,nosuid,noatime
- include: fstab-opts.yml point=/backup opts=noatime
fstab-opts.yml
---
- name: 'Ensure {{ point }} flags'
lineinfile:
path: /etc/fstab
# uses "(not-spaces spaces /tmp spaces )(not-spaces)(the rest)" pattern to match column content and capture args
regexp: '^([^ ]+[ ]+\{{ point }}[ ]+[^ ]+[ ]+)([^ ]+)(.*)'
line: '\1{{ opts }}\3'
backrefs: yes
register: fstab
- name: 'If {{ point }} changed, remount'
command: mount -o remount {{ point }}
when: fstab.changed

Answer 7

i have added the noexec,nodev,nosuid option in /etc/fstab for the /var/tmp mount point.
Requirement is:
Ensure noexec option set on /var/tmp partition
Ensure nodev option set on /var/tmp partition
Ensure nosuid option set on /var/tmp partition
if required install ansible.posix.mount module using below command .
# ansible-galaxy collection install ansible.posix
Playbook:
---
- name: "STEP 1: Get /var/tmp mounted SRC device"
shell: mount | grep -E '\s/var/tmp\s' | awk '{print $1}'
register: "vartmpsrc"
- debug:
msg: "Validated the /var/tmp mount output: {{ vartmpsrc.stdout }}"
- name: "Add mount noexec,nodev,nosuid options for /var/tmp"
mount:
path: "/var/tmp"
src: "{{ vartmpsrc.stdout }}"
fstype: "tmpfs"
opts: "nosuid,nodev,noexec"
state: "present"
when: vartmpsrc.stdout == "/var/tmp"
- name: Remount /var/tmp mounted volume with mount options noexec,nodev,nosuid
ansible.posix.mount:
path: /var/tmp
state: remounted
when: vartmpsrc.stdout == "/var/tmp"
- name: 'STEP 2: Validate noexec,nodev,nosuid option set on /var/tmp partition'
shell: mount | grep -E '\s/var/tmp\s' | grep -v {{ item }}
loop:
- noexec
- nodev
- nosuid
register: vartmp_exists
ignore_errors: yes
when: vartmpsrc.stdout == "/var/tmp"