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,')}}"

For anyone using version 2.0+ `ansible_ssh_host` has been deprecated. This solution still works but you need to replace it with `ansible_host` — Pudding, Feb 09 '17 at 10:36
You wrote you are not too happy with your own anser. You have been pretty close to the best practice. Please set McKelvins as the accepted one now. https://stackoverflow.com/a/39932728/2898712 Thank you. — wedi, Feb 21 '19 at 09:56

score 99 · Answer 1 · edited Nov 23 '20 at 22:24

99

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)

edited Nov 23 '20 at 22:24

Jason Noble

3,756
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answered Oct 08 '16 at 13:08

mckelvin

3,918
1
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22

Note that the alternative only works if all servers have all the main interface set to eth0 – mperrin May 25 '18 at 09:06
3

and note also that `ansible_ssh_host` has been renamed `ansible_host` since ansible 2.0 – mperrin May 25 '18 at 09:16
If you need to add some suffix to each item in the result list (for example, the port number) you can use: `"{{ groups['backend_servers'] | map('extract', hostvars, ['ansible_host']) | map('regex_replace', '^(.*)', '\\1:80') | list }}"` – Stepan Kokhanovskiy Dec 01 '18 at 12:35
5

For the second part `ansible_default_ipv4` might be more reliable, since interface names have become unpredictable.... – Gert van den Berg Jun 10 '19 at 12:30

score 15 · Answer 2 · answered Mar 31 '16 at 11:41

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 %}

Creating a task for that seems a bit overkill. – Forivin Apr 01 '16 at 09:59 — Forivin, Apr 01 '16 at 09:59

score 9 · Answer 3 · answered May 01 '20 at 23:09

9

This do the trick for me. Not relying on the interface name

- main_nodes_ips: "{{ groups['mainnodes'] | map('extract', hostvars, ['ansible_default_ipv4', 'address']) | join(',') }}"

answered May 01 '20 at 23:09

Scandinave

1,388
1
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score 3 · Answer 4 · answered Oct 16 '18 at 16:33

- name: Create List of nodes to be added into Cluster
  set_fact: nodelist={%for host in groups['mygroup']%}"{{hostvars[host].ansible_eth0.ipv4.address}}"{% if not loop.last %},{% endif %}{% endfor %}

 - debug: msg=[{{nodelist}}]

 - name: Set Cluster node list in config file
   lineinfile:
         path: "/etc/myfonfig.cfg"
         line: "hosts: [{{ nodelist }}]"

as results you will have the following line in config file:

hosts: ["192.168.126.38","192.168.126.39","192.168.126.40"]

score 2 · Accepted Answer · answered Mar 31 '16 at 11:09

2

I got it to work on my own now. I'm not too happy about the solution, but it will do:

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

answered Mar 31 '16 at 11:09

Forivin

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8

@McKelvin's answer should be the accepted solution, because it's far superior to this one and the recommended way by the Ansible official documentation to do it. – Strahinja Kustudic Mar 24 '17 at 14:50

Ilshat Karazbayev · Answer 6 · 2018-04-13T18:24:10.240

I've done this by using ansible facts in a playbook. This playbook takes ansible_all_ipv4_addresses list and ansible_nodename (which is actually fully qualified domain name), iterates through all hosts and saves the data in localpath_to_save_ips file on your localhost. You can change localpath_to_save_ips to the absolute path on your localhost.

---
- hosts: all
  become: yes
  gather_facts: yes

  tasks:
  - name: get ip
    local_action: shell echo {{ ansible_all_ipv4_addresses }} {{ ansible_nodename }} >> localpath_to_save_ips

score 1 · Answer 7 · answered Sep 06 '17 at 14:32

I found the "only way" to acceess other group's ip's, when any of the following is true:

some members are not bootstrapped by ansible yet
using serial
group is not part of playbook

Is as follows:

{% set ips=[] %}{% for host in groups['othergroup'] %}{% if ips.append(lookup('dig', host)) %}{% endif %}{% endfor %}{{ ips }}

Requires dnspython on the machine running ansible, install via

sudo apt-get install python-dnspython

If anyone knows a better way given the conditions, I'd love to get rid of this abomination.

score 1 · Answer 8 · answered Feb 25 '20 at 15:39

this is what I did in order to not be relied on eth0 (thanks to ADV-IT's answer):

- name: gathering facts
  hosts: mainnodes
  gather_facts: true

- hosts: mainnodes
  tasks:
    - name: Create List of nodes
      set_fact: nodelist={%for host in groups['mainnodes']%}"{{hostvars[host]['ansible_env'].SSH_CONNECTION.split(' ')[2]}}"{% if not loop.last %},{% endif %}{% endfor %}

score 1 · Answer 9 · answered Nov 17 '21 at 09:19

I ran into a similar problem getting the IP address of a node in another group. Using a construct like: the_ip: "{{ hostvars[groups['master'][0]]['ansible_default_ipv4'].address }}" works only when running the group master, which was not part of my playbook (I was running on localhost). I have overcome the problem by adding an extra play to playbook, like:

- hosts: master
  gather_facts: yes
  become: no
  vars: 
    - the_master_ip: "{{ hostvars[groups['master'][0]]['ansible_default_ipv4'].address }}"
  tasks:
  - debug: var=the_master_ip
  - set_fact: the_ip={{ the_master_ip }}

After which I can use the the_ip in the next play of the playbook.

This may also solve the abomination mentioned by @Petroldrake ?

strangely enough I was not able to get this to work elsewhere. In the end I used a solution using `hostvars` taken from https://serverfault.com/questions/962040/sharing-ansible-variable-between-plays — Monger39, Nov 17 '21 at 10:27

score 0 · Answer 10 · answered Jan 03 '22 at 07:09

0

##Just fetch Ip's using -ansible_default_ipv4.address- & redirect to a local file & then use it

name: gathering_facts hosts: hosts gather_facts: true tasks:
- name: Rediret to the file shell: echo "{{ansible_default_ipv4.address}}" >>ipss.txt delegate_to: localhost

answered Jan 03 '22 at 07:09

Vishal

1
1

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Jan 03 '22 at 08:02

Ansible: Get all the IP addresses of a group

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