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Ansible variables come from a variety of sources. It is for example possible to provide host_vars and group_vars by creating YAML files in a subfolder named host_vars and group_vars respectively of the folder containing the inventory file.

How can I list all of the variables Ansible would know about a group or host inside a playbook? Note: I tried ansible -m debug -e 'var=hostvars' host and ansible -m debug -e '- debug: var=hostvars' to no avail.

Hint: ansible <group|host> -m setup is not the correct answer as it does not include all the variables that come from other sources (it only contains { "ansible_facts" : { ... } }. In fact it does not even include variables provided by a dynamic inventory script (via _meta and so on).

Ansible version: 1.9.1.

0

3 Answers 3

53

ansible <host pattern> -m debug -a "var=hostvars[inventory_hostname]" seems to work.
Replace <host pattern> by any valid host pattern.

Valid variable sources (host_vars, group_vars, _meta in a dynamic inventory, etc.) are all taken into account.

With dynamic inventory script hosts.sh:

#!/bin/sh
if test "$1" = "--host"; then
        echo {}
else
        cat <<EOF
{
  "ungrouped": [ "x.example.com", "y.example.com" ],
  "group1": [ "a.example.com" ],
  "group2": [ "b.example.com" ],
  "groups": {
    "children": [ "group1", "group2" ],
    "vars": { "ansible_ssh_user": "user" }
  },
  "_meta": {
    "hostvars": {
      "a.example.com": { "ansible_ssh_host": "10.0.0.1" },
      "b.example.com": { "ansible_ssh_host": "10.0.0.2" }
    }
  }
}
EOF
fi

You can get:

$ chmod +x hosts.sh
$ ansible -i hosts.sh a.example.com -m debug -a "var=hostvars[inventory_hostname]"
a.example.com | success >> {
    "var": {
        "hostvars": {
            "ansible_ssh_host": "10.0.0.1", 
            "ansible_ssh_user": "user", 
            "group_names": [
                "group1", 
                "groups"
            ], 
            "groups": {
                "all": [
                    "x.example.com", 
                    "y.example.com", 
                    "a.example.com", 
                    "b.example.com"
                ], 
                "group1": [
                    "a.example.com"
                ], 
                "group2": [
                    "b.example.com"
                ], 
                "groups": [
                    "a.example.com", 
                    "b.example.com"
                ], 
                "ungrouped": [
                    "x.example.com", 
                    "y.example.com"
                ]
            }, 
            "inventory_hostname": "a.example.com", 
            "inventory_hostname_short": "a"
        }
    }
}
5
  • With ansible 2.0.2, this doesn't seem to work anymore. The output is localhost | SUCCESS => { "hostvars": "<ansible.vars.hostvars.HostVars object at 0x7f320943da10>" }
    – Zulakis
    Feb 25, 2016 at 10:34
  • Suggested edit to use "var=hostvars[inventory_hostname]" on ansible > 2.0 Mar 9, 2016 at 13:37
  • For 1.9.4 it doesn't return the stuff returned by ansible my.hostname.example.com -m setup -i ../my/inventory/hosts.example -u root Mar 11, 2016 at 15:07
  • 1
    This worked for me ansible host-name -m debug -a "var=[var_name]" -i inventory/testing/hosts
    – Montaro
    Sep 18, 2017 at 12:09
  • This worked beautifully for me. Thank you.
    – dfelix
    Oct 10, 2022 at 19:11
5

Adding a small tip to the really good answer above, if you want to programmatically poke around you can

Use the existing answer for hostvars:

ansible -m debug myhost -a "var=hostvars[inventory_hostname].ansible_version"

But ansible_facts is empty because debug doesn't run the setup module. So you need to try something extra like jq after trimming the output to make it valid json.

ansible -m setup myhost | sed 's#.*SUCCESS =>##' | jq .ansible_facts.ansible_all_ipv4_addresses

I thought people might find this useful when investigating the giant wall of text that comes back in ansible facts when you just want one thing like jq .ansible_facts.ansible_devices.vda.size

2

FYI: This github project shows you how to list 90% of variables across all hosts. I find it more globally useful than single host commands. The README includes instructions for building a simple inventory report. It's even more valuable to run this at the end of a playbook to see all the Facts. To also debug Task behaviour use register:

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