How to get IP address from controller's hosts file in Ansible? - ansible

Question

I am having difficulty figuring out to set a fact in my Ansible playbook that contains the IP address of a server that is listed in the /etc/hosts file on my controller. I am running a playbook against my web server which needs the IP address of my file server. I run the command like this:
ansible-playbook deploy-webservers.yml -i inventory.ini -l webservers
My inventory file looks like this:
[fileservers]
prod-fs1.example.com
[webservers]
prod-web1.example.com
[localhost]
127.0.0.1 ansible_connection=local ansible_python_interpreter=/Users/jsmith/.virtualenvs/provision/bin/python
Here is the playbook:
---
hosts: all
gather_facts: yes
become: yes
pre_tasks:
- name: get file server's IP address
command: "grep prod-fs1 /etc/hosts | awk '{ print $1 }'"
register: fs_ip_addr
delegate_to: localhost
- debug: var={{ fs_ip_addr }}
When I run it, I get this error:
TASK [get file server's IP address] ****************************************************************************************
fatal: [prod-web1.example.com -> localhost]: FAILED! => {"changed": true, "cmd": ["grep", "prod-fs1", "/etc/hosts", "|", "awk", "{ print $0 }"], "delta": "0:00:00.010303", "end": "2020-03-03 12:24:36.207656",
"msg": "non-zero return code", "rc": 2, "start": "2020-03-03 12:24:36.197353", "stderr": "grep: |: No such file or directory\ngrep: awk: No such file or directory\ngrep: { print $0 }:
No such file or directory", "stderr_lines": ["grep: |: No such file or directory", "grep: awk: No such file or directory", "grep: { print $0 }: No such file or directory"], "stdout": "/etc/hosts:45.79.99.99 prod-fs1.example.com prod-fs1", "stdout_lines": ["/etc/hosts:45.79.99.99 prod-fs1.example.com prod-fs1"]}
PLAY RECAP ****************************************************************************************************************
prod-web1.example.com : ok=7 changed=0 unreachable=0 failed=1 skipped=0 rescued=0 ignored=0;
It looks like Ansible has a problem parsing the command when it reaches the pipe symbol. Is there a way around this problem?

Answer 1

Try this. No need to delegate to localhost. lookup is running always on the controller
- set_fact:
fs_ip_addr: "{{ (lookup('file', '/etc/hosts').splitlines()|
list|
select('search', search_host)|
list|
first).split().0 }}"
vars:
search_host: "prod-fs1"

Answer 2

The code can be simplified a bit. Note that search_host is a var.
- set_fact:
fs_ip_addr: "{{ lookup('file', '/etc/hosts').splitlines() |
select('search', search_host) |
first | split() | first }}"