lineinfile help (file doesn't exist)

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1

Hi everyone,

I’m still a bit new to Ansible. I really like it, but it can be a little flummoxing at times for a beginner ;).

For example, I am probably going about this the wrong way, but consider these lines from a playbook:

`

  • name: Configure MTA to Local Only – CIS 3.16
    lineinfile: dest=/etc/postfix/main.cf
    regexp=‘^(?i)inet_interfaces.*’
    line=‘inet_interfaces = localhost’
    state=present
    `

This produces the following output:

TASK: [cis | Configure MTA to Local Only -- CIS 3.16] ************************* failed: [devct67.umaryland.edu] => {"failed": true, "item": "", "rc": 257} msg: Destination /etc/postfix/main.cf does not exist !

OK. So, not all of my machines have postfix on them. But if they do, I want to run this ‘lineinfile’ command.

I have considered almost every “when” option I can think of, but most of them fail because it’s a negative test. For example, I wrote a plugin that returns all packages on a system in a dictionary. So I had a line like:

when: "packages['postfix'] == True"

produces:

TASK: [cis | Configure MTA to Local Only -- CIS 3.16] ************************* fatal: [devct67.umaryland.edu] => error while evaluating conditional: umb_packages['postfix'] == True

That fails, however, when postfix isn’t installed, which is exactly what I’m trying to find out.

So- what are my options? How should I be doing this?

2

you can add one extra pre-task before hand to check if the file/service exist then run handlers ( or other tasks with a registered variable e.g. when)

3

Yup, just to echo Walid, I do a similar thing. Check for file/directory, save in register, react in following task.

An example being initialising Postgres databases…

- name: Check for default database
 stat: path={{ postgres.datadir }}/PG_VERSION
 register: pgv
 
- name: Initialise database (if doesn't already exist)
 command: /sbin/service postgresql-9.3 initdb
 when: pgv.stat.exists != true

HTH
4

I addition to conditional checks mentioned, you might also consider using roles to handle this case. You could create a role that installs and configures postfix and then assign it to only those servers which need it. I prefer roles to conditional checks when possible.

–Aaron

5

It looks that Matthew playbook is a CIS benchmark, I am interested in such benchmarks, and checks. to second Aaron, I too use roles with a combination of group variables to handle different nodes configuration