Ansible: Get all the IP addresses of a group

Question

Let's imagine an inventory file like this:

node-01 ansible_ssh_host=192.168.100.101 node-02 ansible_ssh_host=192.168.100.102 node-03 ansible_ssh_host=192.168.100.103 node-04 ansible_ssh_host=192.168.100.104 node-05 ansible_ssh_host=192.168.100.105  [mainnodes] node-[01:04] 

In my playbook I now want to create some variables containing the IP addresses of the group mainnodes:

vars:   main_nodes_ips: "192.168.100.101,192.168.100.102,192.168.100.103,192.168.100.104"   main_nodes_ips_with_port: "192.168.100.101:3000,192.168.100.102:3000,192.168.100.103:3000,192.168.100.104:3000" 

This is what I got so far:

vars:   main_nodes_ips: "{{groups['mainnodes']|join(',')}}"   main_nodes_ips_with_port: "{{groups['mainnodes']|join(':3000,')}}" 

but that would use the host names instead of the IP addresses.

Any ideas how this could be done?

Update:

looking at the docs for a while, I think this would allow me to loop through all the ip adresses:

{% for host in groups['mainnodes'] %}     {{hostvars[host]['ansible_ssh_host']}} {% endfor %} 

But I just can't figure out how to create an array that holds all these IPs. So that I can use the |join() command on them.

Update2:
I just thought I had figured it out... but it turns out that you cannot use the {% %} syntax in the playbook... or can I? Well in the vars section it didn't. :/

vars:   {% set main_nodes_ip_arr=[] %}   {% for host in groups['mesos-slave'] %}      {% if main_nodes_ip_arr.insert(loop.index,hostvars[host]['ansible_ssh_host']) %} {% endif %}   {% endfor %}   main_nodes_ips: "{{main_nodes_ip_arr|join(',')}}"   main_nodes_ips_with_port: "{{main_nodes_ip_arr|join(':3000,')}}" 

Answer 1

I find the magic map extract here.

main_nodes_ips: "{{ groups['mainnodes'] | map('extract', hostvars, ['ansible_host']) | join(',') }}" main_nodes_ips_with_port: "{{ groups['mainnodes'] | map('extract', hostvars, ['ansible_host']) | join(':3000,') }}:3000" 

An alternative(idea comes from here):

main_nodes_ips: "{{ groups['mainnodes'] | map('extract', hostvars, ['ansible_eth0', 'ipv4', 'address']) | join(',') }}" 

(Suppose the interface is eth0)

Answer 2

i came across this problem a while back and this is what i came up with (not optimal, but it works)

--- # playbook.yml   - hosts: localhost     connection: local      tasks:       - name: create deploy template         template:           src: iplist.txt           dest: /tmp/iplist.txt       - include_vars: /tmp/iplist.txt        - debug: var=ip 

and the template file is

ip: {% for h in groups['webservers'] %}  - {{ hostvars[h].ansible_ssh_host }} {% endfor %}