How to exclude localhost from groups when hosts action is localhost with ansible

Question

I have to list all server in a file by using a template.j2. The purpose is to generate a config file up to date with the ansible inventory file. All files are on the ansible server. I have a generate-projectconf.yml, a template.j2 and the inventory file. The problem is that with my method the localhost is also in the generated file. I only want IP that are in the inventory file.

My yml file looks like that

- hosts: localhost
  tasks:
 - name: modif du project.conf
   template: src="template.j2" dest="/tmp/project.conf" 

the template.j2 file

...
ServersList
    {% for host in  groups[servers_to_monitor] %}
    {{ hostvars[host]['ansible_hostname'] }} : {{ hostvars[host]['ansible_eth0']['ipv4']['address'] }}
    {% endfor %}
...

The inventory file looks like that

[DB_Servers]
cas05  ansible_ssh_host=192.168.20.105  ansible_user=ansible
cas06  ansible_ssh_host=192.168.20.106  ansible_user=ansible

[MS_Account_Servers]
acc21  ansible_host=192.168.20.99  ansible_user=ansible
acc22  ansible_host=192.168.20.100  ansible_user=ansible

[MS_Admin_Servers]
adm21  ansible_host=192.168.20.79  ansible_user=ansible
adm22  ansible_host=192.168.20.80  ansible_user=ansible

[MS_Admingui_Servers]
ihm21   ansible_host=192.168.20.81  ansible_user=ansible

To launch this, I execute the command

ansible-playbook  generate-projectconf.yml -i /.../inventory --extra-vars "servers_to_monitor=all"

The result looks like this:

...
dep01 : 192.168.20.3
ihm21 : 192.168.20.81
adm21 : ...
...

Answer 1

Exclude current host (in your case localhost) from list of servers in your template:

{% for host in groups[servers_to_monitor] | difference([inventory_hostname]) %}